九州大学 研究者情報
論文一覧
久枝 良雄(ひさえだ よしお) データ更新日:2019.12.10

教授 /  工学研究院 応用化学部門 生体機能化学講座


原著論文
1. Hui Tian, Hisashi Shimakoshi, Toshikazu Ono, Yoshio Hisaeda, Visible Light-Driven, One-pot Amide Synthesis Catalyzed by the B
12
Model Complex under Aerobic Conditions, ChemPlusChem, 10.1002/cplu.201800522, 84, 3, 237-240, 2019.03, [URL], A visible light responsive catalytic system with the B
12
complex as the catalyst and [Ir(dtbbpy)(ppy)
2
]PF
6
as the photosensitizer was developed. It provides a convenient and efficient way to synthesize amides. Based on this method, trichlorinated organic compounds were converted into amides in the presence of an amine under aerobic conditions at room temperature in a one-pot procedure. Various trichlorinated organic compounds and an amine source, such as primary, secondary, and cyclic amines, have been evaluated for this transformation, providing the expected products in moderate to excellent yields. Notably, product formation depended on the reaction atmosphere where the amide was obtained under aerobic conditions while partially dechlorinated products were obtained under anaerobic conditions. As this protocol is free from hazardous reagents, extra additives, noble metals, and dangerous gas, the present method provides a novel and efficient approach for amide synthesis under mild and easily controlled conditions..
2. Hui Tian, Hisashi Shimakoshi, Toshikazu Ono, Yoshio Hisaeda, Visible-Light-Driven, One-pot Amide Synthesis Catalyzed by the B
12
Model Complex under Aerobic Conditions, ChemPlusChem, 10.1002/cplu.201800586, 84, 3, 2019.03, [URL], Invited for this month's cover is the group of Prof. Dr. Hisashi Shimakoshi at Kyushu University, Japan. The front cover shows “le mariage” of an iridium complex and a vitamin B
12
derivative with two wedding rings in the background. This collaboration of two complexes is induced by visible light in the presence of air to achieve green molecular transformations. This protocol was applied to the synthesis of amides from a wide range of trichlorinated organic compounds. Read the full text of the article at 10.1002/cplu.201800522..
3. Toshikazu Ono, Yoshio Hisaeda, Flexible-color tuning and white-light emission in three-, four-, and five-component host/guest co-crystals by charge-transfer emissions as well as effective energy transfers, Journal of Materials Chemistry C, 10.1039/c8tc06165c, 7, 10, 2829-2842, 2019.01, [URL], Three-, four-, and five-component host/guest crystals with multi-color and white light emission is described. Our strategy is based on the confinement of aromatic donor guests in supramolecular acceptor hosts. The supramolecular acceptor hosts (NDI-TPFB) were composed of N,N′-dipyrid-3-yl-1,4,5,8-naphthalenediimide (NDI) with two tris(pentafluorophenyl)borane (TPFB) linked by boron-nitrogen dative bonds as Lewis acid-base pairs, which spontaneously formed upon mixing the components. In the first part, a set of three-component crystals with 14 different aromatic guests were characterized to elucidate the structure-property relationships. In the latter part, a series of 17 types of four- and five-component crystals were formed with the use of binary or ternary guest inclusion systems, and their structural and photophysical properties were investigated. Among them, 14 types of crystals were formed effectively without destroying the crystal structure, as determined by X-ray diffraction and fluorescence microscopy. Notably, flexible color tuning, including white light emission, was realized by tuning the guest ratio and the combinations. Various intermolecular interactions such as C-H⋯F interactions, π-π stacking, charge-transfer interactions, and inclusion phenomena were important for forming the crystals. This approach that yields a rational solution of multicomponent crystals could be potentially useful for obtaining novel photofunctional solid-state systems..
4. Md Jakir Hossain, Toshikazu Ono, Yoshio Yano, Yoshio Hisaeda, Learning From Vitamin B
12
-Mediated Reactions
Cobalt(III)−Carbon-Assisted Catalytic C−H Difluoroacylation of (Hetero)Arenes through Controlled-Potential Electrolysis, ChemElectroChem, 10.1002/celc.201900164, 2019.01, [URL], The synthesis of difluoromethylated (CF
2
R) (R=H, alkyl/aryl, CO
2
R, etc.) compounds has received considerable attention in recent years. In this study, the cobalt(III)−carbon-mediated catalytic C−H difluoroacylation of unactivated arenes and heteroarenes using BrCF
2
CO
2
Et is reported. This catalytic cycle is based on a valence change of the cobalt catalyst, a naturally derived vitamin B
12
derivative, driven by controlled-potential electrolysis at −0.8 V vs. Ag/AgCl under visible-light irradiation in dimethyl sulfoxide. A broad substrate scope is demonstrated, and two compounds were characterized according to their X-ray crystal structures. Mechanistic studies showed that the reaction proceeds through a radical pathway mediated by homolytic cleavage of the cobalt(III)–carbon bond. A turnover number of more than 100 was observed, owing to the inherent stability of the vitamin B
12
framework. This naturally derived catalytic system has potential applications in medicinal chemistry and materials science..
5. Hisashi Shimakoshi, Noriyuki Houfuku, Li Chen, Yoshio Hisaeda, Redox active ionic liquid as efficient mediator and solvent for visible light-driven B
12
catalytic reactions, Green Energy and Environment, 10.1016/j.gee.2019.03.001, 2019.01, [URL], The redox active ionic liquid, 1-ethyl-4-(methoxycarbonyl)pyridinium bis(trifluoromethanesulfonyl)amide (RIL), was synthesized from its iodide form by an anion exchange reaction of Li(NTf
2
) with viscos liquid (η = 122 cP at 25 °C) and characterized by NMR, IR, and elemental analysis. The compound showed reversible redox couples at −0.65 V and −1.48 V vs. Ag/AgCl and worked as an electron mediator in the B
12
complex/[Ru(bpy)
3
]Cl
2
photosensitizer catalytic system under visible light irradiation. The catalytic efficiency in the RIL was higher than those in DMF, MeOH, and the redox inactive ionic liquid, 1-butyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)amide..
6. Koichi Hashimoto, Taro Koide, Toru Okawara, Hisashi Shimakoshi, Yuta Hori, Yoshihito Shiota, Kazunari Yoshizawa, Yoshio Hisaeda, Redox behaviour of the β-dihydroporphycene cobalt complex
study on the effect of hydrogenation of the ligand, Dalton Transactions, 10.1039/c8dt03743d, 48, 3, 872-881, 2019.01, [URL], The dihydrogenated porphycene cobalt(ii) complex was synthesized and electrochemical experiments were carried out. The one-electron reduction of the complex proceeded at the central metal to afford the Co(i) species; in contrast, for the non-hydrogenated porphycene cobalt(ii) complex, the one-electron reduction gave the ligand reduced radical anion species. The reactivity of the one-electron reduced species with alkyl halides showed clear differences between the complexes. Hydrogenation of the β-position of the porphycene makes it possible to generate a central cobalt reduced species possessing a higher reactivity than the ligand reduced radical anion species..
7. Li Chen, Yoshio Hisaeda, Hisashi Shimakoshi, Visible Light-Driven, Room Temperature Heck-Type Reaction of Alkyl Halides with Styrene Derivatives Catalyzed by B
12
Complex, Advanced Synthesis and Catalysis, 10.1002/adsc.201801707, 2019.01, [URL], A visible light driven Heck-type coupling reaction of alkyl halides with styrene and its derivatives catalyzed by the cobalamin derivative (B
12
) with the [Ru(bpy)
3
]Cl
2
photosensitizer at room temperature is reported. The catalytic efficiencies of the B
12
catalyst were compared to that of other cobalt complexes such as cobaloxime. Various control experiments supported a radical-based mechanism similar to those for typical B
12
model reactions. A unique coupling reaction combined with 1,2-migration of the functional group is also reported. Mild reaction conditions using an environmentally benign cobalt catalyst derived from the natural B
12
provided a practical protocol for the synthetic organic chemistry of the B
12
catalyzed reaction system. (Figure presented.)..
8. Toshikazu Ono, Ai Taema, Aiko Goto, Yoshio Hisaeda, Switching of Monomer Fluorescence, Charge-Transfer Fluorescence, and Room-Temperature Phosphorescence Induced by Aromatic Guest Inclusion in a Supramolecular Host, Chemistry - A European Journal, 10.1002/chem.201804349, 24, 66, 17487-17496, 2018.11, [URL], Crystal engineering of three-component crystals with guest-dependent photoluminescence switching, including (i) crystallization-induced emission enhancement, (ii) intermolecular charge-transfer emission, and (iii) room-temperature phosphorescence under ultraviolet irradiation, was demonstrated. This strategy was based on the confinement of aromatic guests in a supramolecular host (denoted as EBPDI-TPFB) composed of 5,5′-(ethyne-1,2-diyl)bis(2-pyridin-3-yl-isoindoline-1,3-dione (EBPDI) with two tris(pentafluorophenyl)borane (TPFB) molecules linked by B−N dative bonds that acted as Lewis pairs. The single-crystal X-ray structures of complexes with eight different guests were collected, revealing that the size and/or shape of the supramolecular host EBPDI-TPFB was modulated by the included guest molecules. The excellent guest inclusion ability of EBPDI-TPFB allowed systematic photoluminescence regulation of the complexes, which exhibited multicolor emissions in the crystalline state. Photoluminescence switching characteristics of the complexes were observed upon removing the guests or mechanical grinding of the crystals. These results indicated that using the host–guest chemistry of multicomponent crystals not only facilitates crystallization, but also can reveal hidden optical functions by combining molecules of interest, which should contribute to the fields of physical chemistry and materials science..
9. Keishiro Tahara, Ling Pan, Toshikazu Ono, Yoshio Hisaeda, Learning from b12 enzymes
Biomimetic and bioinspired catalysts for eco-friendly organic synthesis, Beilstein Journal of Organic Chemistry, 10.3762/bjoc.14.232, 14, 2553-2567, 2018.10, [URL], Cobalamins (B12) play various important roles in vivo. Most B12-dependent enzymes are divided into three main subfamilies: adenosylcobalamin-dependent isomerases, methylcobalamin-dependent methyltransferases, and dehalogenases. Mimicking these B12 enzyme functions under non-enzymatic conditions offers good understanding of their elaborate reaction mechanisms. Furthermore, bio-inspiration offers a new approach to catalytic design for green and eco-friendly molecular transformations. As part of a study based on vitamin B12 derivatives including heptamethyl cobyrinate perchlorate, we describe biomimetic and bioinspired catalytic reactions with B12 enzyme functions. The reactions are classified according to the corresponding three B12 enzyme subfamilies, with a focus on our recent development on electrochemical and photochemical catalytic systems. Other important reactions are also described, with a focus on radical-involved reactions in terms of organic synthesis..
10. Hisashi Shimakoshi, Yoshio Hisaeda, Electrochemistry and catalytic properties of vitamin B12 derivatives in nonaqueous media, Current Opinion in Electrochemistry, 10.1016/j.coelec.2017.12.001, 8, 24-30, 2018.03, [URL], Electroorganic synthesis mediated by vitamin B12 derivatives has been developed in nonaqueous media. Especially, amphiphilic heptamethyl cobyrinate with a high solubility in various organic solvents was used in various kinds of electroorganic syntheses based on enzymatic function. Electrolysis of an organic halide catalyzed by the B12 model complex provided dechlorinated products under anaerobic conditions, while the electrolysis under aerobic conditions afforded oxidized products such as an ester and amide with dechlorination. Electrochemical reductions of an alkene and alkyne were also catalyzed by the B12 model complex at less negative applied potentials than those of the alkene and alkyne reductions. A bioinspired intermediate, expected as a cobalt–hydrogen complex, should be formed and catalyze the reaction..
11. Ying Sun, Wei Zhang, Tian Yi Ma, Yu Zhang, Hisashi Shimakoshi, Yoshio Hisaeda, Xi Ming Song, Enhanced photocatalytic activity of a B12-based catalyst co-photosensitized by TiO2 and Ru(II) towards dechlorination, RSC Advances, 10.1039/c7ra13037f, 8, 2, 662-670, 2018.01, [URL], A novel hybrid photocatalyst denoted as B12-TiO2-Ru(ii) was prepared by co-immobilizing a B12 derivative and trisbipyridine ruthenium (Ru(bpy)3 2+) on the surface of a mesoporous anatase TiO2 microspheres and was characterized by DRS, XRD, SEM and BET et al. By using the hybrid photocatalyst, DDT was completely didechlorinated and a small part of tridechlorinated product was also detected in the presence of TEOA only after 30 min of visible light irradiation. Under simulated sunlight, the hybrid exhibited a significantly enhanced photocatalytic activity for dechlorination compared with B12-TiO2 under the same condition or itself under visible light irradiation due to the additivity in the contribution of UV and visible part of the sunlight to the electron transfer. In addition, this hybrid catalyst can be easily reused without loss of catalytic efficiency. This is the first report on a B12-based photocatalyst co-sensitized by two photosensitizers with wide spectral response..
12. Taro Koide, Isao Aritome, Tatsuya Saeki, Yoshitsugu Morita, Yoshihito Shiota, Kazunari Yoshizawa, Hisashi Shimakoshi, Yoshio Hisaeda, Cobalt-Carbon Bond Formation Reaction via Ligand Reduction of Porphycene-Cobalt(II) Complex and Its Noninnocent Reactivity, ACS Omega, 10.1021/acsomega.8b00239, 3, 4, 4027-4034, 2018.01, [URL], The interesting redox properties and reactivity of metalloporphycene have been studied for decades; however, the detailed experimental investigation on the reactivity and reaction mechanism under inert condition combined with theoretical calculations had not been performed so far. In this study, the novel reactivity of the reduced form of the cobalt porphycene with alkyl halides to form cobalt-carbon (Co-C) bonds was revealed. Under electrochemical reductive conditions, not the central cobalt, but the ligand was reduced and reacted with alkyl halides to afford the cobalt-alkyl complexes under N2 atmosphere in a glovebox. The reaction mechanism was clarified by the combination of experimental and theoretical studies that the porphycene ligand works as a noninnocent ligand and allows the SN2-type Co-C bond formation. This result provides us the possibility of the reaction triggered by the reduction of ligand with macrocyclic π-conjugated system, not by the reduction of metal..
13. Masaaki Abe, Hiroto Mukotaka, Taro Fujioka, Toru Okawara, Kei Umegaki, Toshikazu Ono, Yoshio Hisaeda, First entry into nonmetal-centred porphycenes
Synthesis of a phosphorus(v) complex of octaethylporphycene, Dalton Transactions, 10.1039/c7dt04471b, 47, 8, 2487-2491, 2018.01, [URL], A phosphorus(v) complex of porphycene [P(OEPc)(OMe)2]PF6 (OEPc = 2,3,6,7,12,13,16,17-octaethylporphycenato dianion) has been synthesized and structurally characterized as the first porphycene derivative incorporating nonmetal elements in the macrocyclic cavity. An extremely low energy level of the LUMO is observed, which is rationalized by the low-lying π∗ orbital of the porphycene ring coupled with the insertion of the highly-inductive pentavalent phosphorus centre. The compound is luminescent in bright red with a quantum yield of 22.7% in CH2Cl2 at 298 K..
14. Hisashi Shimakoshi, Yoshio Hisaeda, Bioinspired molecular transformations by biorelated metal complexes combined with electrolysis and photoredox systems, Yuki Gosei Kagaku Kyokaishi/Journal of Synthetic Organic Chemistry, 10.5059/yukigoseikyokaishi.76.894, 76, 9, 894-903, 2018.01, [URL], Naturally-occurring B 12(cobalamin)-dependent enzymes catalyze various molecular transformations that are of particular interest from the viewpoint of biological chemistry as well as synthetic organic chemistry. As bioorganometallic compounds are considered as intermediate for B 12-dependent reactions, those were utilized as catalysts for various molecular transformations. Using the unique property of the B 12 compound, various catalytic reactions have been developed using its model complex. Electroorganic syntheses mediated by the B 12 complex have been developed as green molecular transformations. The redox active B 12 complex shows a unique catalysis in organic synthesis such as the dechlorination of organic halides and the radical mediated isomerization reactions. The B 12 complex-photosensitizer composites have also become a green and efficient catalyst for molecular transformations. The B 12-dependent enzymes mimic reactions catalytically occurring using the B 12 complex-photosensitizer composites. In addition to the B 12 mimic reaction, novel bioinspired reactions were also developed, such as hydrogen production or alkene and alkyne reductions, and the cobalt-hydrogen complex was considered as a putative intermediate of the reactions..
15. Toshikazu Ono, Ning Xu, Daiki Koga, Toshihiro Ideo, Manabu Sugimoto, Yoshio Hisaeda, Gram-scale synthesis of porphycenes through acid-catalyzed oxidative macrocyclizations of E/Z-mixed 5,6-diaryldipyrroethenes, RSC Advances, 10.1039/c8ra09040h, 8, 69, 39269-39273, 2018.01, [URL], The gram-scale production of porphycene derivatives is reported. This has been achieved by acid-catalyzed ring closure of an E/Z-mixture of 5,6-diaryldipyrroethenes, resulting in the formation of meso-tetraarylporphycenes in yields of up to 80%. E/Z-isomerization of the 5,6-diaryldipyrroethenes under acidic conditions was key to proceed the effective macrocyclization..
16. Toshikazu Ono, Kosuke Wakiya, Md Jakir Hossain, Hisashi Shimakoshi, Yoshio Hisaeda, Synthesis of trifluoromethylated B12 derivative and photolysis of cobalt(III)-trifluoromethyl bond, Chemistry Letters, 10.1246/cl.180355, 47, 8, 979-981, 2018.01, [URL], A vitamin B12 derivative with a trifluoromethyl group as an axial ligand, heptamethyl trifluoromethylaquacobyrinate perchlorate, [[(CF3)(H2O)Cob(III)7C1ester]ClO4], is prepared and characterized by elemental analysis, 1H NMR, 19F NMR, ESI-MS, UV-vis absorption, and cyclic voltammetry. The Co-CF3 complex shows homolysis of the Co(III)-CF3 bond under visible light irradiation, which releases a CF3 radical that can be detected by a radical trapping experiment..
17. Toshikazu Ono, Daiki Koga, Kenji Yoza, Yoshio Hisaeda, The first synthesis of meso-dicycloalkylporphycenes
ring strain effects on structural and optical properties of isomeric porphyrins, Chemical Communications, 10.1039/c7cc07170a, 53, 91, 12258-12261, 2017.11, [URL], Two novel meso-dicycloalkylporphycenes, namely meso-dicyclopentyl- (Cy5Pc) and meso-dicyclohexylporphycenes (Cy6Pc) are synthesized for the first time in porphycene chemistry. We use intermolecular oxidative coupling of 5,6-dicycloalkydipyrroethenes mediated by hypervalent iodine(iii) reagents. The solution fluorescence maxima of Cy5Pc are more than 400 times as intense as that of Cy6Pc. The results suggested that photoluminescence switching is achieved through the ring strain perturbation of the meso-substituted cycloalkyl groups on the porphycene cavity..
18. Keishiro Tahara, Ling Pan, Ryoko Yamaguchi, Hisashi Shimakoshi, Masaaki Abe, Yoshio Hisaeda, Impact of the corrin framework of vitamin B12 on the electrochemical carbon-skeleton rearrangement in comparison to an imine/oxime planar ligand; tuning selectivity in 1,2-migration of a functional group by controlling electrolysis potential, Journal of Inorganic Biochemistry, 10.1016/j.jinorgbio.2017.07.021, 175, 239-243, 2017.10, [URL], Among the coenzyme B12-dependent enzymes, methylmalonyl-CoA mutase (MMCM) catalyzes the carbon-skeleton rearrangement reaction between R-methylmalonyl-CoA and succinyl-CoA. Diethyl 2-bromomethyl-2-phenylmalonate, an alkyl bromide substrate having two different migrating groups (phenyl and carboxylic ester groups) on the β-carbon, was applied to the electrolysis mediated by a hydrophobic vitamin B12 model complex, heptamethyl cobyrinate perchlorate in this study. The electrolysis of the substrate at − 1.0 V vs. Ag-AgCl by light irradiation afforded the simple reduced product (diethyl 2-methyl-2-phenylmalonate) and the phenyl migrated product (diethyl 2-benzyl-2-phenylmalonate), as well as the electrolysis of the substrate at − 1.5 V vs. Ag-AgCl in the dark. The electrolysis of the substrate at − 2.0 V vs. Ag-AgCl afforded the carboxylic ester migrated product (diethyl phenylsuccinate) as the major product. The selectivity for the migrating group was successfully tuned by controlling the electrolysis potential. We clarified that the cathodic chemistry of the Co(III) alkylated heptamethyl cobyrinate is critical for the selectivity of the migrating group through mechanistic investigations and comparisons to the simple vitamin B12 model complex, an imine/oxime-type cobalt complex..
19. Ying Sun, Wei Zhang, Jian Tong, Yu Zhang, Shuyao Wu, Daliang Liu, Shimakoshi Hisashi, Yoshio Hisaeda, Xi-Ming Song, Significant enhancement of visible light photocatalytic activity of the hybrid B12-PIL/rGO in the presence of Ru(bpy)32+ for DDT dehalogenation, RSC Advances, 7, 19197–19204 (2017)., 10.1039/c7ra02062g, 2017.03.
20. Toshikazu Ono, Y. Tsukiyama, A. Taema, Yoshio Hisaeda, Inclusion Crystal Growth and Optical Properties of Organic Charge-transfer Complexes Built from Small Aromatic Guest Molecules and Naphthalenediimide Derivatives, Chem. Lett., 46, No.6, 801-804 (2017)., 10.1246/cl.161019, 2017.03.
21. Hisashi Shimakoshi, Z. Luo, K. Tomita, Yoshio Hisaeda, Cathodic Reductive Couplings and Hydrogenations of Alkenes and Alkynes Catalyzed by the B12 Model Complex, J. Organometal. Chem., 839, 71-77 (2017)., http://doi.org/10.1016/j.jorganchem.2017.02.002, 2017.02.
22. Hisashi Shimakoshi, Yoshio Hisaeda, Hybrid Catalyst for Light-Driven Green Molecular Transformations, ChemPlusChem, 82, No.1, 18-29 (2017). (Back Cover), 10.1002/cplu.201600303, 2017.01.
23. Toshikazu Ono, Daiki Koga, Yoshio Hisaeda, Facile Synthesis of 9,10,19,20-Tetraalkylporphycenes, Chem. Lett., 46, No.2, 260-262 (2017)., 10.1246/cl.161019, 2017.01.
24. Keishiro Tahara, Ling Pan, Ryoko Yamaguchi, Hisashi Shimakoshi, Masaaki Abe, Yoshio Hisaeda, Reprint of
Impact of the corrin framework of vitamin B12 on the electrochemical carbon-skeleton rearrangement in comparison to an imine/oxime planar ligand; tuning selectivity in 1,2-migration of a functional group by controlling electrolysis potential, Journal of Inorganic Biochemistry, 10.1016/j.jinorgbio.2017.09.021, 2017.01, [URL], Among the coenzyme B12-dependent enzymes, methylmalonyl-CoA mutase (MMCM) catalyzes the carbon-skeleton rearrangement reaction between R-methylmalonyl-CoA and succinyl-CoA. Diethyl 2-bromomethyl-2-phenylmalonate, an alkyl bromide substrate having two different migrating groups (phenyl and carboxylic ester groups) on the β-carbon, was applied to the electrolysis mediated by a hydrophobic vitamin B12 model complex, heptamethyl cobyrinate perchlorate in this study. The electrolysis of the substrate at -1.0V vs. Ag-AgCl by light irradiation afforded the simple reduced product (diethyl 2-methyl-2-phenylmalonate) and the phenyl migrated product (diethyl 2-benzyl-2-phenylmalonate), as well as the electrolysis of the substrate at -1.5V vs. Ag-AgCl in the dark. The electrolysis of the substrate at -2.0V vs. Ag-AgCl afforded the carboxylic ester migrated product (diethyl phenylsuccinate) as the major product. The selectivity for the migrating group was successfully tuned by controlling the electrolysis potential. We clarified that the cathodic chemistry of the Co(III) alkylated heptamethyl cobyrinate is critical for the selectivity of the migrating group through mechanistic investigations and comparisons to the simple vitamin B12 model complex, an imine/oxime-type cobalt complex..
25. Toshikazu Ono, Daiki Koga, Kenji Yoza, Yoshio Hisaeda, The first synthesis of
Meso -dicycloalkylporphycenes: Ring strain effects on structural and optical properties of isomeric porphyrins, Chemical Communications, 10.1039/c7cc07170a, 53, 91, 12258-12261, 2017.01, [URL], Two novel meso-dicycloalkylporphycenes, namely meso-dicyclopentyl- (Cy5Pc) and meso-dicyclohexylporphycenes (Cy6Pc) are synthesized for the first time in porphycene chemistry. We use intermolecular oxidative coupling of 5,6-dicycloalkydipyrroethenes mediated by hypervalent iodine(iii) reagents. The solution fluorescence maxima of Cy5Pc are more than 400 times as intense as that of Cy6Pc. The results suggested that photoluminescence switching is achieved through the ring strain perturbation of the meso-substituted cycloalkyl groups on the porphycene cavity..
26. Hisashi Shimakoshi, Yoshio Hisaeda, A Hybrid Catalyst for Light-Driven Green Molecular Transformations, ChemPlusChem, 10.1002/cplu.201600303, 82, 1, 18-29, 2017.01, [URL], This Minireview is focused on the development of hybrid catalysts composed of photosensitizers and a metal complex, especially vitamin B12 derivatives. The semiconductor–metal complex composites are effective photocatalysts for molecular transformations due to the synergistic effect between the two components. The design of a B12 complex for the hybridization with TiO2 was simple and straightforward—cobyrinic acid, having seven carboxylic groups derived from naturally occurring B12 is stably immobilized on the TiO2. By using the hybrid catalysts as mimics of B12-dependent enzymes, light-driven reactions such as the dechlorination of organic halide pollutants, and radical-mediated isomerization proceeded catalytically. In addition to the enzyme-mimicking reactions, bioinspired reactions were also developed with the hybrid catalyst. The B12–TiO2 hybrid catalyst was used for hydrogen evolution and alkene reduction by UV light irradiation, and the cobalt–hydrogen complex (Co–H complex) was considered to be a putative intermediate of the reactions. The multidisciplinary concept for the design of a hybrid catalyst is described in this Minireview..
27. Toshikazu Ono, Daiki Koga, Yoshio Hisaeda, Facile synthesis of 9,10,19,20-tetraalkylporphycenes, Chemistry Letters, 10.1246/cl.161019, 46, 2, 260-262, 2017.01, [URL], meso-Tetraalkylporphycenes were synthesized in a few steps using intramolecular oxidative coupling of the Z-isomer of 5,6-dialkyldipyrroethenes. The use of a hypervalent iodine(III) reagent, namely phenyliodine(III) bis(trifluoroacetate), is essential for performing these reactions..
28. Hui Tian, Hisashi Shimakoshi, Gyurim Park, Sinheui Kim, Youngmin You, Yoshio Hisaeda, Photocatalytic function of the B12 complex with the cyclometalated iridium(III) complex as a photosensitizer under visible light irradiation, Dalton Transactions, 10.1039/c7dt03742b, 47, 3, 675-683, 2017.01, [URL], A visible light induced three-component catalytic system with the cobalamin derivative (B12) as a catalyst, the cyclometalated iridium(iii) complex (Irdfppy, Irppy, Irpbt and [Ir{dF(CF3)ppy}2(dtbpy)]PF6) as a photosensitizer and triethanolamine as an electron source under N2 was developed. This catalytic system showed a much higher catalytic efficiency than the previous catalytic system using [Ru(ii)(bpy)3]Cl2 as the photosensitizer for the dechlorination reaction of 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT). Noteworthy is the fact that the remarkable high turnover number (over ten thousand) based on B12, which ranks at the top among the reported studies, was obtained when Irdfppy was used as a photosensitizer. This photocatalytic system was also successfully applied to the B12 enzyme-mimic reaction, i.e., the 1,2-migration of the phenyl group of 2-bromomethyl-2-phenylmalonate. The plausible reaction mechanism was proposed, which involved two quenching pathways, an oxidative quenching pathway and a reductive quenching pathway, to be responsible for the initial electron transfer of the excited-state photosensitizers during the DDT dechlorination reaction. Transient photoluminescence experiments revealed that the oxidative quenching of the photosensitizer dominated over the reductive quenching pathway..
29. Ying Sun, Wei Zhang, Jian Tong, Yu Zhang, Shuyao Wu, Daliang Liu, Hisashi Shimakoshi, Yoshio Hisaeda, Xi Ming Song, Significant enhancement of visible light photocatalytic activity of the hybrid B12-PIL/rGO in the presence of Ru(bpy)3 2+ for DDT dehalogenation, RSC Advances, 10.1039/c7ra02062g, 7, 31, 19197-19204, 2017.01, [URL], A new B12-PIL/rGO hybrid was prepared successfully through immobilizing a B12 derivative on the surface of poly(ionic liquid) (PIL)-modified reduced graphene oxide (rGO) by electrostatic attraction and π-π stacking attraction among the different components. The hybrid catalyst showed an enhanced photocatalytic activity in the presence of Ru(bpy)3 2+ for 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) dechlorination with ∼100% conversion. Especially, the yield of didechlorinated products could reach 78% after 1 h of visible light irradiation, which should be attributed to a synergistic effect of B12, rGO and PIL in B12-PIL/rGO, including their respective catalytic performance, the excellent electron transport of rGO and the concentration of DDT and 1,1-bis(4-chlorophenyl)-2,2-dichloroethane (DDD) on the surface of B12-PIL/rGO. Furthermore, the hybrid catalyst was easily recycled for use without obvious loss of catalytic activity..
30. Joji Ohshita, Yohei Matsumura, Takahiro Nakayama, Hiroto Yoshida, Atsutaka Kunai, Yoshio Hisaeda, Takashi Hayashi, meso-tetraaryl(porphyrinato)cobalt(III)-catalyzed oxygenation of disilanes under aerobic conditions, Chemistry Letters, 10.1246/cl.170857, 46, 12, 1807-1809, 2017.01, [URL], Cobalt(III) porphyrin-catalyzed oxygenation of disilanes is investigated. Five- and six-membered cyclic disilanes are readily oxygenated, providing the corresponding cyclic disiloxanes in 75%-quant yield. We propose a reaction mechanism involving intermediates with a Co(III)Si bond based on spectroscopic analysis of the reaction mixtures..
31. Md Jakir Hossain, Toshikazu Ono, Kosuke Wakiya, Yoshio Hisaeda, A Vitamin B12 derivative catalyzed electrochemical trifluoromethylation and perfluoroalkylation of arenes and heteroarenes in organic media, Chemical Communications, 10.1039/c7cc06221d, 53, 79, 10878-10881, 2017, [URL], The electrochemical trifluoromethylation and perfluoroalkylation of aromatic compounds mediated by a vitamin B12 derivative as a cobalt-based catalyst has been developed. The Co(i) species of a vitamin B12 derivative, prepared by controlled-potential electrolysis at -0.8 V vs. Ag/AgCl in methanol, reacted with RfI (Rf = CF3, n-C3F7, n-C4F9, n-C8F17, and n-C10F21) to form a Co-Rf complex. This complex released an Rf radical under visible light irradiation, which then reacted directly with non-activated (hetero)arenes to form the desired fluoroalkylated molecules through direct C-H functionalization. To our knowledge, this is the first report of a naturally derived vitamin B12 catalyzed trifluoromethylation and perfluoroalkylation of aromatic compounds as a cobalt-mediated catalyst..
32. Toshikazu Ono, Yoshifumi Tsukiyama, Ai Taema, Yoshio Hisaeda, Inclusion crystal growth and optical properties of organic charge-transfer complexes built from small aromatic guest molecules and naphthalenediimide derivatives, Chemistry Letters, 10.1246/cl.170122, 46, 6, 801-804, 2017, [URL], Inclusion crystals were effectively formed from a simple naphthalenediimide derivative with toluene, 4-fluorotoluene, and p-xylene by the aid of cooperative intermolecular interactions, such as charge-transfer interactions and inclusion phenomena. The crystals showed intense guest-dependent solid-state emission based on ground state CT complexes between naphthalenediimide and small aromatic guests..
33. Hui Tian, Hisashi Shimakoshi, Kenji Imamura, Yoshihito Shiota, Kazunari Yoshizawa, Yoshio Hisaeda, Photocatalytic alkene reduction by a B12-TiO2 hybrid catalyst coupled with C-F bond cleavage for
Gem -difluoroolefin synthesis, Chemical Communications, 10.1039/c7cc04377e, 53, 68, 9478-9481, 2017, [URL], Photocatalytic syntheses of gem-difluoroolefins were performed using the B12-TiO2 hybrid catalyst during the CC bond reduction of α-trifluoromethyl styrenes with C-F bond cleavage at room temperature under nitrogen. The gem-difluoroolefins were used as synthetic precursors for fluorinated cyclopropanes..
34. Soichiro Yoshimoto, Teppei Kawamoto, Toru Okawar, Yoshio Hisaeda, Masaaki Abe, Conformational Change in Molecular Assembly of Nickel(II) Tetra(n-propyl)porphycene Triggered by Potential Manipulation, Langmuir, 32, No.51, 13635-13639 (2016)., 10.1021/acs.langmuir.6b03782, 2016.11.
35. Hisashi Shimakoshi, Zhongli Luo, Kazuya Tomita, Yoshio Hisaeda, Cathodic reductive couplings and hydrogenations of alkenes and alkynes catalyzed by the B12 model complex, Journal of Organometallic Chemistry, 10.1016/j.jorganchem.2017.02.002, 2016.11, [URL], The reductive coupling and hydrogenation of alkenes were catalyzed by the B12 model complex, heptamethyl cobyrinate perchlorate (1), in the presence of acid during electrolysis at -0.7 V vs. Ag/AgCl in acetonitrile. Conjugated alkenes showed a good reactivity during electrolysis to form reduced products. The product distributions were dependent on the substituents at the CC bond of the alkenes. ESR spin-trapping experiments using 5,5-dimethylpyrroline N-oxide (DMPO) revealed that the cobalt-hydrogen complex (CoH complex) should be formed during the electrolysis and it functioned as an intermediate for the alkene reduction. The electrolysis was also applied to an alkyne, such as phenylacetylene, to form 2,3-diphenylbutane (racemic and meso) and ethylbenzene via styrene as reductive coupling and hydrogenated products, respectively..
36. Sou Hatanaka, Toshikazu Ono, Yoshio Hisaeda, Turn-on Fluorogenic and Chromogenic Detection of Small Aromatic Hydrocarbon Vapors by a Porous Supramolecular Host, Chem. Eur. J., 22, No.30, 10346 –10350 (2016)., 10.1002/chem.201601812, 2016.08.
37. Shuyao Wu, Jiali Chen, Daliang Liu, Qian Zhuang, Qi Pei, Lixin Xia, Qian Zhang, Jun-ichi Kikuchi, Yoshio Hisaeda, Xi-Ming Song, A Biocompatible Cerasome Based Platform for Direct Electrochemistry of Cholesterol Oxidase and Cholesterol Sensing, RSC Advances, 6, No.75, 70781-70790 (2016)., 10.1039/c6ra06368c, 2016.08.
38. Hui Mao, Jiachen Liang, Chunguang Ji, Haifeng Zhang, Qi Pei, Yuyang Zhang, Yu Zhang, Yoshio Hisaeda, Xi-Ming Song, Poly(zwitterionic liquids) functionalized polypyrrole/graphene oxide nanosheets for electrochemically detecting dopamine at low concentration, Materials Science and Engineering C, 65, 143 –150 (2016)., 10.1016/j.msec.2016.04.023, 2016.07.
39. Hisashi Shimakoshi, Zhongli Luo, Yoshio Hisaeda, Electrolysis of Trichloromethylated Organic Compounds under Aerobic Conditions Catalyzed by B12 Model Complex for Ester and Amide Formations, Dalton Trans., 45, No.25, 10173-10180 (2016). (Back Cover), 10.1039/c6dt00556j, 2016.06.
40. M. Giedyk, Hisashi Shimakoshi, D. Gryko, Yoshio Hisaeda, Electrochemistry and Catalytic Properties of Amphiphilic Vitamin B12 Derivatives in Nonaqueous Media, Dalton Trans., 45, No.20, 8340-8346 (2016). (Inside Front Cover), 10.1039/c6dt00355a, 2016.05.
41. Yoshitsugu Morita, Koji Oohora, Akiyoshi Sawada, Kazuki Doitomi, Jun Ohbayashi, Takashi Kamachi, Yoshizawa Kazunari, Yoshio Hisaeda, Takashi Hayashi, Intraprotein transmethylation via a CH3–Co(III) species in myoglobin reconstituted with a cobalt corrinoid complex, Dalton Trans., 45, No.8, 3277-3284 (2016). (Front Cover), 10.1039/c5dt04109k, 2016.04.
42. Yoshitsugu Morita, Koji Oohora, Yoshio Hisaeda, Takashi Hayashi, Intraprotein transmethylation via a CH3–Co(III) species in myoglobin reconstituted with a cobalt corrinoid complex, Dalton Trans., 45, No.8, 3277-3284 (2016). , 10.1039/c5dt04109k, 2016.03.
43. Hui Mao, Jiachen Liang, Yoshio Hisaeda, Xi-Ming Song, Poly(zwitterionic liquids) functionalized polypyrrole/graphene oxide nanosheets for electrochemically detecting dopamine at low concentration, Materials Science and Engineering C, 65, 143 –150 (2016)., 10.1039/c5dt04109k, 2016.03.
44. K. Tahara, K. Mikuriya, Yoshio Hisaeda, Supramolecular System Composed of B12 Model Complex and Organic Photosensitizer: Impact of the Corrin Framework of B12 on the Visible-Light-Driven Dechlorination without the Use of Noble Metals, Supramolecular Chemistry, 28, No.1-2, 141-150 (2016)., http://dx.doi.org/10.1080/10610278.2015.1103373, 2016.02.
45. Keishiro Tahara, Kumiko Mikuriya, Takahiro Masuko, Jun Ichi Kikuchi, Yoshio Hisaeda, Supramolecular system composed of B12 model complex and organic photosensitizer
Impact of the corrin framework of B12 on the visible-light-driven dechlorination without the use of noble metals, Supramolecular Chemistry, 10.1080/10610278.2015.1103373, 28, 1-2, 141-150, 2016.02, [URL], The visible-light-driven dechlorination system without the use of a noble metal has been developed. We screened the combination of cobalt catalysts having square-planar monoanionic ligands (hydrophobic B12 model complex 1/imine-oxime type complex 2) and typical red dyes (Rose Bengal 3/Rhodamine B 4/Nile Red 5) for the construction of a dehalogenation system via a noble-metal-free and visible-light-driven process. The combination of the hydrophobic B12 model complex 1 and Rose Bengal 3 exhibited the highest catalytic activity to 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) to form the monodechlorinated compound, 1,1-bis(4-chlorophenyl)-2,2-dichloroethane, as the major product. The prolonged photocatalysis of DDT by the B12-Rose Bengal system afforded the tri-dechlorinated compound, trans-4,4′-dichlorostilbene, as the major product. Furthermore, we investigated the mechanism of the dehalogenation cycle using various methods such as UV-vis spectroscopy and laser flash photolysis. Finally, we clarified the advantage of using the hydrophobic B12 model complex 1 as an electron acceptor as well as a cobalt catalyst in the organic dye-involved photocatalysis..
46. Masaaki Abe, T. Majima, Yoshio Hisaeda, Covalently-Attached Porphycene–Ferrocene Dyads: Synthesis, Redox-Switched Emission, and Observation of the Charge-Separated State, Inorg. Chem., 55 (1), 7-9 (2016)., 10.1021/acs.inorgchem.5b02078, 2016.01.
47. Masaaki Abe, Hiroaki Yamada, Toru Okawara, Mamoru Fujitsuka, Tetsuro Majima, Yoshio Hisaeda, Covalently Attached Porphycene-Ferrocene Dyads
Synthesis, Redox-Switched Emission, and Observation of the Charge-Separated State, Inorganic Chemistry, 10.1021/acs.inorgchem.5b02078, 55, 1, 7-9, 2016.01, [URL], Two new porphycenes functionalized with ferrocenyl pendants have been synthesized and characterized spectroscopically and structurally. The porphycene-based emission in porphycene-ferrocene dyads was switched on and off by the reversible control of the ferrocenyl pendant redox states. Transient absorption spectroscopy with a femtosecond laser-pulsed technique has successfully detected the picosecond charge-separated excited state of the dyad upon Q-band excitation of the porphycene ring..
48. Masaaki Abe, Toshikazu Ono, Nobuo Kimizuka, Yoshio Hisaeda, An Electropolymerized Crystalline Film Incorporating Axially-Bound Metalloporhycenes: Remarkable Reversibility, Reproducibility, and Coloration Efficiency of Ruthenium(II/III)-Based Electrochromism, Inorg. Chem., 54 (23), 11061-11063 (2015)., 10.1021/acs.inorgchem.5b02129, 2015.12.
49. Hisashi Shimakoshi, Yoshio Hisaeda, Oxygen-Controlled Catalysis by Vitamin B12-TiO2
Formation of Esters and Amides from Trichlorinated Organic Compounds by Photoirradiation, Angewandte Chemie - International Edition, 10.1002/anie.201507782, 54, 51, 15439-15443, 2015.12, [URL], An oxygen switch in catalysis of the cobalamin derivative (B12)-TiO2 hybrid catalyst for the dechlorination of trichlorinated organic compounds has been developed. The covalently bound B12 on the TiO2 surface transformed trichlorinated organic compounds into an ester and amide by UV light irradiation under mild conditions (in air at room temperature), while dichlorostilbenes (E and Z forms) were formed in nitrogen from benzotrichloride. A benzoyl chloride was formed as an intermediate of the ester and amide, which was detected by GC-MS. The substrate scope of the synthetic strategy is demonstrated with a range of various trichlorinated organic compounds. A photo-duet reaction utilizing the hole and conduction band electron of TiO2 in B12-TiO2 for the amide formation was also developed..
50. Hisashi Shimakoshi, Yoshio Hisaeda, Oxygen-Controlled Catalysis of B12-TiO2: Formation of Ester and Amide from Trichlorinated Organic Compounds by Photoirradiation, Angew. Chem. Int. Ed., 54, 15439 –15443 (2015)., 10.1021/jacs.5b04178, 2015.11, An oxygen switch in catalysis of the cobalamin derivative (B12)-TiO2 hybrid catalyst for the dechlorination of trichlorinated organic compounds has been developed. The covalently bound B12 on the TiO2 surface transformed trichlorinated organic compounds into an ester and amide by UV light irradiation under mild conditions (in air at room temperature), while dichlorostilbenes (E and Z forms) were formed in nitrogen from benzotrichloride. A benzoyl chloride was formed as an intermediate of the ester and amide, which was detected by GC-MS. The substrate scope of the synthetic strategy is demonstrated with a range of various trichlorinated organic compounds. A photo-duet reaction utilizing the hole and conduction band electron of TiO2 in B12-TiO2 for the amide formation was also developed..
51. Masaaki Abe, Hiroki Futagawa, Toshikazu Ono, Teppei Yamada, Nobuo Kimizuka, Yoshio Hisaeda, An Electropolymerized Crystalline Film Incorporating Axially-Bound Metalloporphycenes
Remarkable Reversibility, Reproducibility, and Coloration Efficiency of Ruthenium(II/III)-Based Electrochromism, Inorganic Chemistry, 10.1021/acs.inorgchem.5b02129, 54, 23, 11061-11063, 2015.11, [URL], Oxidative electropolymeization of an axially bound, bithiophene-pyridine complex of ruthenium(III)-porphycene [Ru(TPrPc) (btp)2]PF6 (1) gives a submicrometer-thick, polymeric film on an ITO electrode with a crystalline morphology. The polymeric film, the first example of axially linked multimetalloporphycene coordination arrays, exhibits highly stable and reproducible electrochromic response with high electrochromic efficiency upon electrochemical control over the metal-centered electron transfer process (RuII/RuIII)..
52. Hui Mao, Yang Song, Yoshio Hisaeda, Xi-Ming Song, One-step preparation of flower-like poly(styreneco-zwitterionic ionic liquid) microspheres with hierarchical structures for supported acidic heterogeneous catalysts, RSC Adv., 5, No.111, 91654–91664 (2015)., 10.1039/c5ra16463j, 2015.09.
53. Toshikazu Ono, Yoshio Hisaeda, Manabu Sugimoto, Multicomponent Molecular Puzzles for Photofunction Design: Emission Color Variation in Lewis Acid–Base Pair Crystals Coupled with Guest-to-Host Charge Transfer Excitation, J. Am. Chem. Soc., 137, No.30, 9519–9522 (2015)., 10.1021/jacs.5b04178, 2015.08, Simple yet ubiquitous multimolecular assembly systems with color-tunable emissions are realized by cooperative electron donor−acceptor interactions, such as the boron−nitrogen (B−N) dative bond as a Lewis acid−base pair and charge transfer (CT) interactions. These are ternary-component systems consisting of a naphthalenediimide derivat ive (NDI) , t r i s -(pentafluorophenyl)borane (TPFB), and aromatic molecules (guest) with an NDI:TPFB:guest ratio of 1:2:2. The crystal shows guest-dependent color-tunable emissions such as deep blue to orange when a guest molecule of benzene is replaced with other π-conjugated systems. A good correlation between the emission wavelength and ionization potential of the guest and electronic structure calculations indicated that the emission is due to the CT transition from the guest to the NDI. The present study suggests that a rational solution of multcomponent molecular puzzles would be useful for obtaining novel photofunctional solid-state systems..
54. Yu Zhang, Qi Pei, Yoshio Hisaeda, Xi-Ming Song, Mesoporous TiO2-Based Photoanode Sensitized by BiOI and Investigation of Its Photovoltaic Behavior, Langmuir, 31, No.37, 10275-10284 (2015)., 10.1021/acs.langmuir.5b02248, 2015.08.
55. Toshikazu Ono, Manabu Sugimoto, Yoshio Hisaeda, Multicomponent molecular puzzles for photofunction design
Emission color variation in lewis acid-base pair crystals coupled with guest-to-host charge transfer excitation, Journal of the American Chemical Society, 10.1021/jacs.5b04178, 137, 30, 9519-9522, 2015.08, [URL], Simple yet ubiquitous multimolecular assembly systems with color-tunable emissions are realized by cooperative electron donor-acceptor interactions, such as the boron-nitrogen (B-N) dative bond as a Lewis acid-base pair and charge transfer (CT) interactions. These are ternary-component systems consisting of a naphthalenediimide derivative (NDI), tris(pentafluorophenyl)borane (TPFB), and aromatic molecules (guest) with an NDI:TPFB:guest ratio of 1:2:2. The crystal shows guest-dependent color-tunable emissions such as deep blue to orange when a guest molecule of benzene is replaced with other conjugated systems. A good correlation between the emission wavelength and ionization potential of the guest and electronic structure calculations indicated that the emission is due to the CT transition from the guest to the NDI. The present study suggests that a rational solution of multcomponent molecular puzzles would be useful for obtaining novel photofunctional solid-state systems..
56. Xu, J., Hisashi Shimakoshi, Yoshio Hisaeda, Development of Metal-Organic Framework (MOF)-B12 system as new bio-inspired heterogeneous catalyst , J. Organometal. Chem., doi:10.1016/j.jorganchem.2014.11.015, 782, 89-95, 2015.04, A novel bimetal complex {Zn4Ru2(bpdc)4·4C2NH8·9DMF}n (1) (H2bpdc = 4,4′-biphenyldicarboxylic acid) was synthesized by the solvothermal method. The results of the X-ray crystallographic analysis revealed that 1 crystallizes in the orthorhombic Pna21 space group, which has a 3D 2-fold interpenetrated hex framework, with open channel sizes along the [010] direction of ca. 1.4 nm × 1.4 nm. The photosensitizer [Ru(bpy)3]2+ was adsorbed into the 1 to form Ru@MOF by cation exchanging. A cobalamin derivative (B12), heptamethyl cobyrinate, was also effectively immobilized on Ru@MOF, and the resulting hybrid complex, B12–Ru@MOF, exhibited a high reactivity for the dechlorination reaction of 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) under an N2 atmosphere by visible light irradiation in the solid state. The catalysis of B12–Ru@MOF can still reach more than a ca. 80% conversion after third recyclings. Furthermore, the heterogeneous catalyst, B12–Ru@MOF, was useful for the cobalamin-dependent reaction, such as the 1,2-migration of the acetyl group..
57. Okawara, T, Yoshio Hisaeda, Synthesis, Characterizations, and Intramolecular Quenching Behavior of an Axially-Linked Trinuclear Molecular Wire Containing Ruthenium(II) Porphycenes, Rapid Communication in Photoscience, http://dx.doi.org/10.5857/RCP.2015.4.1.22, Rapid Communication in Photoscience, 4, No.1, 22-24 (2015)., 2015.04, A new trinuclear complex [Ru(TPrPc)(CO)]2[Ru(pytpy)2](PF6)2 (TPrPc = 2,7,12,17-tetra-n-propylporphycenato dianion and pytpy = 4′-(4-pyridyl)-2,2′:6′,2″-terpyridine) has been synthesized and characterized as the first example of a discrete molecular wire containing metalloporohycenes as a building block. The trinuclear complex shows multiple-step redox behavior in 0.1 M n-Bu4NPF6–dichloromethane. The mononuclear [Ru(pytpy)2]2+ precursor shows emission at 640 nm (deaerated acetone, 298 K) upon illumination at the metal-to-ligand charge transfer (MLCT) band at 495 nm, but the trinuclear molecular wire is found to be non-emissive upon photoexcitation at the central [Ru(pytpy)2]2+ entity, indicating an efficient quenching ability of the axially-linked, ruthenium(II)–porphycene chromophores in an intramolecular fashion..
58. Hisashi Shimakoshi, Nagami, Y., Yoshio Hisaeda, Crystal Structure Dependence for Reactivities of B12-TiO2 Hybrid Catalysts with Anatase and Rutile Forms, Rapid Communication in Photoscience, in press., 2015.04, The debromination of phenethyl bromide by the B12- TiO2 hybrid catalyst under UV light irradiation was investigated. The catalytic efficiency was dependent on the type of TiO2. The anatase form of TiO2 was superior to the rutile form of TiO2. The selectivity of the product was also dependent on the crystal structure of TiO2, and the rutile form of TiO2 showed a high selectivity for the formation of the coupling product, 2,3-diphenylbutane, when compared to that of the anatase form of TiO2..
59. Jing Xu, Hisashi Shimakoshi, Yoshio Hisaeda, Development of metal-organic framework (MOF)-B12 system as new bio-inspired heterogeneous catalyst, Journal of Organometallic Chemistry, 10.1016/j.jorganchem.2014.11.015, 782, 89-95, 2015.04, [URL], Abstract A novel bimetal complex {Zn4Ru2(bpdc)4·4C2NH8·9DMF}n (1) (H2bpdc = 4,4′-biphenyldicarboxylic acid) was synthesized by the solvothermal method. The results of the X-ray crystallographic analysis revealed that 1 crystallizes in the orthorhombic Pna21 space group, which has a 3D 2-fold interpenetrated hex framework, with open channel sizes along the [010] direction of ca. 1.4 nm × 1.4 nm. The photosensitizer [Ru(bpy)3]2+ was adsorbed into the 1 to form Ru@MOF by cation exchanging. A cobalamin derivative (B12), heptamethyl cobyrinate, was also effectively immobilized on Ru@MOF, and the resulting hybrid complex, B12-Ru@MOF, exhibited a high reactivity for the dechlorination reaction of 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) under an N2 atmosphere by visible light irradiation in the solid state. The catalysis of B12-Ru@MOF can still reach more than a ca. 80% conversion after third recyclings. Furthermore, the heterogeneous catalyst, B12-Ru@MOF, was useful for the cobalamin-dependent reaction, such as the 1,2-migration of the acetyl group..
60. Yoshio Hisaeda, Toru Okawara, Masaaki Abe, Shiho Ashigara, Molecular structures, redox properties, and photosubstitution of ruthenium(II) carbonyl complexes of porphycene , J. Porphyrins Phthalocyanines 19, 233 (2015)., DOI: 10.1142/S1088424614501120, Toru Okawara
Masaaki Abe
Shiho Ashigara
Yoshio Hisaeda
, 2015.03.
61. Okawara, T., Doi, A., Toshikazu Ono, Masaaki Abe, Takehara, K., Yoshio Hisaeda, Matsushima, S., Synthesis and X-ray crystallography of bipyrroles: impacts of a CO-π interaction on their structure and photoluminescent properties, Tetrahedron Lett., 10.1016/j.tetlet.2015.01.159, 56, 11, 1407-1410, 2015.03, Crystal structures and solid-state emission properties of tetraalkyl 4,4′-dimethyl-2,2′-bipyrrole-3,3′,5,5′-tetracarboxylates (alkyl=methyl, ethyl, and isopropyl) have been investigated. Single crystal X-ray diffraction studies revealed that all bipyrroles are co-planar due to an intramolecular hydrogen bonding. The isopropyl derivative exhibited a CO⋯π interaction in the solid-state and showed the longest emission wavelength because of increase in structural flexibility..
62. Toru Okawara, Masaaki Abe, Shiho Ashigara, Yoshio Hisaeda, Molecular structures, redox properties, and photosubstitution of ruthenium(II) carbonyl complexes of porphycene, Journal of Porphyrins and Phthalocyanines, 10.1142/S1088424614501120, 19, 1-3, 233-241, 2015.01, [URL], Two ruthenium(II) carbonyl complexes of porphycene, (carbonyl)(pyridine)(2,7,12,17-tetra-n-propylporphycenato)ruthenium(II) (1) and (carbonyl)(pyridine)(2,3,6,7,12,13,16,17-octaethylpor-phycenato)ruthenium(II) (2), have been structurally characterized by single-crystal X-ray diffraction analysis. Cyclic voltammetry has revealed that the porphycene complexes undergo multiple oxidations and reductions in dichloromethane and the reduction potentials are highly positive compared to porphyrin analogs. UV-light irradiation (400 nm or shorter wavelength region) of a benzene solution of 1 and 2 containing external pyridine leads to dissociation of the carbonyl ligand from the ruthenium(II) centers to give the corresponding bis-pyridine complexes. The identical reaction has been also studied for a porphyrin derivative (carbonyl)(pyridine)(2,3,7,8,12,13,17,18-octaethylporphyriato)ruthenum(II) (3). The first-order kinetic analysis has revealed that the photosubstitution of all of the compounds occurs in the order of 10-3 s-1 at 298 K but proceeds faster for complexes of porphycene (1 and 2) than that of porphyrin (3)..
63. Okawara, T., Masaaki Abe, Yoshio Hisaeda, Synthesis of a series of multiply meso-acetoxylated porphycenes, Tetrahedron Lett, doi:10.1016/j.tetlet.2014.09.057, 55, 6193-6197, 2014.11, A series of multiply meso-substituted porphycenes has been prepared by acetoxylation of 2,7,12,17-tetra-n-propylporphycene (H2TPrPc), and the molecular structure of 9,10-diacetoxy-2,7,12,17-tetra-n-propylporphycene (2a) determined by single-crystal X-ray diffraction analysis. The 1H NMR and optical properties have also been investigated.
.
64. Toru Okawara, Masaaki Abe, Yoshio Hisaeda, Synthesis of a series of multiply meso-acetoxylated porphycenes, Tetrahedron Letters, 10.1016/j.tetlet.2014.09.057, 55, 45, 6193-6197, 2014.11, [URL], A series of multiply meso-substituted porphycenes has been prepared by acetoxylation of 2,7,12,17-tetra-n-propylporphycene (H2TPrPc), and the molecular structure of 9,10-diacetoxy-2,7,12,17-tetra-n-propylporphycene (2a) determined by single-crystal X-ray diffraction analysis. The 1H NMR and optical properties have also been investigated..
65. Takashi Hayashi, Yoshitsugu Morita, Eiichi Mizohata, Koji Oohora, Jun Ohbayashi, Tsuyoshi Inoue, Yoshio Hisaeda, Co(ii)/Co(i) reduction-induced axial histidine-flipping in myoglobin reconstituted with a cobalt tetradehydrocorrin as a methionine synthase model, Chemical Communications, 10.1039/c4cc05448b, 50, 83, 12560-12563, 2014.10, [URL], A conjugate between apomyoglobin and cobalt tetradehydrocorrin was prepared to replicate the coordination behavior of cob(i)alamin in methionine synthase. X-ray crystallography reveals that the tetra-coordinated Co(i) species is formed through the cleavage of the axial Co-His93 ligation after the reduction of the penta-coordinated Co(ii) cofactor in the heme pocket..
66. Hisashi Shimakoshi, Yoshio Hisaeda, B12-TiO2 Hybrid Catalyst for Light-Driven Hydrogen Production and Hydrogenation of C-C Multiple Bonds, ChemPlusChem [Back Cover], DOI: 10.1002/cplu.201402081, 79, 9, 1250-1253, 2014.09, The B12-TiO2 hybrid catalyst mediates H2O reduction to form hydrogen under UV irradiation (turnover number of one per hour). The catalyst also mediates reductions of alkenes such as styrene derivatives and alkylacrylates (maximum turnover number of 100 per hour) under mild conditions of room temperature, ordinary pressure, and water or alcohol as solvent..
67. Hisashi Shimakoshi, Yoshio Hisaeda, B12-TiO2 Hybrid Catalyst for Light-Driven Hydrogen Production and Hydrogenation of C-C Multiple Bonds, ChemPlusChem, 10.1002/cplu.201402081, 79, 9, 1250-1253, 2014.09, [URL], The B12-TiO2 hybrid catalyst mediates H2O reduction to form hydrogen under UV irradiation (turnover number of one per hour). The catalyst also mediates reductions of alkenes such as styrene derivatives and alkylacrylates (maximum turnover number of 100 per hour) under mild conditions of room temperature, ordinary pressure, and water or alcohol as solvent..
68. Hayashi, T., Morita, Y., Mizohata, E., Ohbayashi, J., Inoue, T., Yoshio Hisaeda, Co(II)/Co(I) reduction-induced axial histidine-flipping in myoglobin reconstituted with a cobalt tetradehydrocorrin as a methionine synthase model, Chem. Commun., DOI: 10.1039/C4CC05448B, 50, 83, 12560-12563, 2014.08, A conjugate between apomyoglobin and cobalt tetradehydrocorrin was prepared to replicate the coordination behavior of cob(I)alamin in methionine synthase. X-ray crystallography reveals that the tetra-coordinated Co(I) species is formed through the cleavage of the axial Co–His93 ligation after the reduction of the penta-coordinated Co(II) cofactor in the heme pocket..
69. Zhang, W., Hisashi Shimakoshi, Yoshio Hisaeda, A Polymerized Ionic Liquid-supported B12 Catalyst with a Ruthenium Trisbipyridine Photosensitizer for Photocatalytic Dechlorination in Ionic Liquids, Dalton Trans., DOI: 10.1039/C4DT01360C, 43, 13972-13978, 2014.07, By immobilizing a B12 complex and a Ru(II) trisbipyridine photosensitizer in a polymerized ionic liquid (PIL), a visible light-driven photocatalyst was developed. The synthesized copolymer was characterized by GPC and DLS, and using UV-vis absorption spectra and luminescence spectra. The Ru(II) trisbipyridine photosensitizer in the copolymer showed an enhanced emission compared to that of the monomer in the ionic liquid, 1-butyl-4-methylimidazolium bis(trifluoromethanesulfonyl)amide ([C4mim][NTf2]). Formation of the Co(I) species of the B12 complex in the copolymer was confirmed by the UV-vis spectral change in [C4mim][NTf2] containing a sacrificial reductant (triethanolamine) under irradiation with visible light. The copolymer showed a high photocatalytic activity in various ionic liquids for 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) dechlorination with [similar]99% conversion after visible light irradiation for 2 h. Furthermore, both the B12 catalyst and photosensitizer in the polymer were easily recycled for use with the ionic liquid solvent without any loss of catalytic activity..
70. Qiao, Y., Tahara, K., Zhang, Q., Song, X.-M., Yoshio Hisaeda, Construction of Molecular Communication Interface Formed from Cerasome and Hydrophobic Vitamin B12 on Glassy Carbon Electrode, Chem. Lett., http://doi.org/10.1246/cl.140025, 43, 684-686, 2014.05, Nanohybrid vesicles formed from a cationic cerasome, i.e., a morphologically stable liposomal membrane with a ceramic surface and a hydrophobic vitamin B12 as a bioinspired molecular catalyst were assembled on a glassy carbon electrode to form a molecular communication interface. This interface effectively converted a molecular input signal to an electric response..
71. Motwani, H. V., Hisashi Shimakoshi, Golding, B. T., Törnqvist, M., Yoshio Hisaeda, Alkylcobyrinate from Sucralose and Mechanistic Aspects of its Co-C Bond Cleavage, Tetrahedron Letters, doi:10.1016/j.tetlet.2014.03.028, 55, 2667-2670, 2014.04, Reaction of heptamethyl cob(I)yrinate with 1′,6′-dichloro-1′,6′-dideoxy-β-d-fructofuranosyl-4-chloro-4-deoxy-α-d-galactopyranoside (sucralose) gave an alkylcobyrinate, heptamethyl-6′-[α-d-galactopyranoside- 1′-chloro-1′,6′-dideoxy-β-d-fructofuranosyl-4-chloro-4-deoxy]cobyrinate perchlorate, [(Suc)Cob(III)7C1ester]ClO4. Cleavage behavior of Cosingle bondC bond of the alkylcobyrinate was investigated under various conditions (hν, H+ and reduction) using UV–vis spectroscopy combined with the EPR spin-trapping technique, and by cyclic voltammetry..
72. Ikegami, A, Masaaki Abe, Yoshio Hisaeda, A Heterometallic Protocol for Turn-On Fluorescence. Synthesis, Structure, and Luminescence Behavior of Diruthenium(III)-Magnesium(II) Complex Decorated with Four Pyrenecarboxylates, Chem. Lett., http://doi.org/10.1246/cl.131093, 43, 456-458, 2014.04, A new heterometallic diruthenium(III)–magnesium(II) complex functionalized with four pyrenecarboxylate fluorophores 1 has been synthesized and structurally characterized. Fluorescence from the pyrene moieties in 1 was nearly completely quenched in CH2Cl2 (>98%), but turn-on fluorescence was successfully observed after regioselective substitution of the carboxylates bridging the heterometallic Ru(III)···Mg(II) sites..
73. Hitesh V. Motwani, Hisashi Shimakoshi, Bernard T. Golding, Margareta Törnqvist, Yoshio Hisaeda, Alkylcobyrinate from sucralose and mechanistic aspects of its CoC bond cleavage, Tetrahedron Letters, 10.1016/j.tetlet.2014.03.028, 55, 16, 2667-2670, 2014.04, [URL], Reaction of heptamethyl cob(I)yrinate with 1′,6′-dichloro- 1′,6′-dideoxy-β-d-fructofuranosyl-4-chloro-4-deoxy-α-d- galactopyranoside (sucralose) gave an alkylcobyrinate, heptamethyl-6′- [α-d-galactopyranoside- 1′-chloro-1′,6′-dideoxy-β- d-fructofuranosyl-4-chloro-4-deoxy]cobyrinate perchlorate, [(Suc)Cob(III)7C 1ester]ClO4. Cleavage behavior of CoC bond of the alkylcobyrinate was investigated under various conditions (hν, H+ and reduction) using UV-vis spectroscopy combined with the EPR spin-trapping technique, and by cyclic voltammetry..
74. Y. Qiao, K. Tahara, Q. Zhang, X.-M. Song, Yoshio Hisaeda, J. Kikuch, Construction of Molecular Communication Interface Formed from Cerasome and Hydrophobic Vitamin B12 on Glassy Carbon Electrode, Chem. Lett., DOI: 10.1246/cl.140025, 43, 2014.03.
75. A.Ikegami, Masaaki Abe, Yoshio Hisaeda, A Heterometallic Protocol for Turn-on Fluorescence. Synthesis, Structure, and Luminescence Behavior of a Diruthenium(III)Magnesium(II) Complex Decorated with Four Pyrenecarboxylates, Chem. Lett., DOI: 10.1246/cl.131093, 43, No.42, 2014.02.
76. H. V. Motwani, Hisashi Shimakoshi, B. T. Golding, M. Törnqvist, Yoshio Hisaeda, Alkylcobyrinate from Sucralose and Mechanistic Aspects of its Co-C bond Cleavages, Tetrahedron Lett., DOI: http://dx.doi.org/10.1016/j.tetlet.2014.03.028, 55, No.16, 2667-2670, 2014.01.
77. Atsushi Ikegami, Masaaki Abe, Yoshio Hisaeda, A heterometallic protocol for turn-on fluorescence. synthesis, structure and luminescence behavior of a diruthenium(III)magnesium(II) complex decorated with four pyrenecarboxylates, Chemistry Letters, 10.1246/cl.131093, 43, 4, 456-458, 2014.01, [URL], A new heterometallic diruthenium(III)magnesium(II) complex functionalized with four pyrenecarboxylate fluorophores 1 has been synthesized and structurally characterized. Fluorescence from the pyrene moieties in 1 was nearly completely quenched in CH2 Cl2 (>98%), but turn-on fluorescence was successfully observed after regioselective substitution of the carboxylates bridging the heterometallic Ru(III)..Mg(II) sites..
78. Wei Zhang, Hisashi Shimakoshi, Noriyuki Houfuku, Xi Ming Song, Yoshio Hisaeda, A polymerized ionic liquid-supported B12 catalyst with a ruthenium trisbipyridine photosensitizer for photocatalytic dechlorination in ionic liquids, Dalton Transactions, 10.1039/c4dt01360c, 43, 37, 13972-13978, 2014.01, [URL], By immobilizing a B12 complex and a Ru(ii) trisbipyridine photosensitizer in a polymerized ionic liquid (PIL), a visible light-driven photocatalyst was developed. The synthesized copolymer was characterized by GPC and DLS, and using UV-vis absorption spectra and luminescence spectra. The Ru(ii) trisbipyridine photosensitizer in the copolymer showed an enhanced emission compared to that of the monomer in the ionic liquid, 1-butyl-4-methylimidazolium bis(trifluoromethanesulfonyl)amide ([C 4mim][NTf2]). Formation of the Co(i) species of the B 12 complex in the copolymer was confirmed by the UV-vis spectral change in [C4mim][NTf2] containing a sacrificial reductant (triethanolamine) under irradiation with visible light. The copolymer showed a high photocatalytic activity in various ionic liquids for 1,1-bis(4- chlorophenyl)-2,2,2-trichloroethane (DDT) dechlorination with ∼99% conversion after visible light irradiation for 2 h. Furthermore, both the B 12 catalyst and photosensitizer in the polymer were easily recycled for use with the ionic liquid solvent without any loss of catalytic activity..
79. Yun Qiao, Keishiro Tahara, Qian Zhang, Xi Ming Song, Yoshio Hisaeda, Jun Ich Kikuchi, Construction of molecular communication interface formed from cerasome and hydrophobic vitamin b12 on glassy carbon electrode, Chemistry Letters, 10.1246/cl.140025, 43, 5, 684-686, 2014.01, [URL], Nanohybrid vesicles formed from a cationic cerasome, i.e., a morphologically stable liposomal membrane with a ceramic surface and a hydrophobic vitamin B12 as a bioinspired molecular catalyst were assembled on a glassy carbon electrode to form a molecular communication interface. This interface effectively converted a molecular input signal to an electric response..
80. Masatsugu Taneda, Akihiro Tanaka, Hisashi Shimakoshi, Atsushi Ikegami, Koichi Hashimoto, Masaaki Abe, Yoshio Hisaeda, Synthesis and characterizations of meso-disubstituted asymmetric porphycenes, Tetrahedron Letters, 10.1016/j.tetlet.2013.08.026, 54, 42, 5727-5729, 2013.10, [URL], A post-synthetic method has been developed to synthesize novel asymmetric porphycenes bearing two different substituents on the meso-positions. Nitration of 9-acetoxy-2,7,12,17-tetra-n-propylporphycene with AgNO3 in CH 3COOH/CH2Cl2 occurs regioselectively at the 19-position of the macrocycle to give 9-acetoxy-19-nitro-2,7,12,17-tetra-n- propylporphycene (3a) which was readily converted to 9-acetoxy-19-amino-2,7,12, 17-tetra-n-propylporphycene (4a) by the reduction with SnCl2 in pyridine..
81. M. Taneda, A. Tanaka, A.Ikegami, K.Hashimoto, Masaaki Abe, Yoshio Hisaeda, Synthesis and characterizations of meso-disubstituted asymmetric porphycenes, Tetrahedron Lett., DOI: 10.1016/j.tetlet.2013.08.026, 54, No.42, 5727-5729, 2013.07.
82. Yoshio Hisaeda, Keishiro Tahara, Hisashi Shimakoshi, Takahiro Masuko, Bioinspired catalytic reactions with vitamin B12 derivative and photosensitizers, Pure and Applied Chemistry, 10.1351/PAC-CON-12-10-05, 85, 7, 1415-1426, 2013.07, [URL], As part of a study directed toward design of good catalytic systems based upon a hydrophobic vitamin B12, heptamethyl cobyrinate perchlorate, we describe the preparation of various nanomaterials using the vitamin B12 derivative and photosensitizers. Examples include vitamin B12-hyperbranched polymers (HBPs), human serum albumin (HSA) containing vitamin B12 derivatives, a vitamin B12-titanium dioxide hybrid catalyst, a vitamin B12-Ru complex combined system, and a vitamin B12-rose bengal combined system. These bioinspired materials have the potential as catalytic systems for the degradation of organic halide pollutants and for molecular transformations via radical intermediates during irradiation by UV or visible light, and offer a variety of applications that are of great interest in terms of green chemistry..
83. Keishiro Tahara, Ayaka Matsuzaki, Takahiro Masuko, Jun Ichi Kikuchi, Yoshio Hisaeda, Synthesis, characterization, Co-S bond reactivity of a vitamin B 12 model complex having pentafluorophenylthiolate as an axial ligand, Dalton Transactions, 10.1039/c3dt00042g, 42, 18, 6410-6416, 2013.07, [URL], Heptamethyl (aquo)(pentafluorophenylthiolate)cobyrinate perchlorate, [(H2O)(C6F5S)Cob(iii)7C1ester] ClO4, was synthesized as a B12 model complex having a thiolate ligand in the axial position. The axial ligand change in heptamethyl (diaquo)cobyrinate diperchlorate, [(H2O)2Cob(iii)7C 1ester](ClO4)2, from H2O to C 6F5S- afforded the B12-thiolate complex. The B12-thiolate model complex was characterized by UV-vis, NMR and ESI-mass spectroscopies. The coordination of C6F 5S- to the cobalt center affected the spectroscopic properties of the corrin ring through the electronic interaction between the axial ligand (C6F5S-) and the equatorial ligand (corrin). The photolysis of the B12-thiolate model complex led to the homolytic cleavage of the Co(iii)-S bond to form the Co(ii) complex and the phenyl thiyl radical. The thermolysis of the B12-thiolate model complex also led to the homolytic cleavage of the Co(iii)-S bond. Furthermore, the reactivity of the Co(iii)-S bond of the B12-thiolate model complex was applied to the catalytic oxidation of C6F5SH to C6F5S-SC6F5..
84. Yoshio Hisaeda, K. Tahara, Hisashi Shimakoshi, T. Masuko, Bioinspired Catalytic Reactions with Vitamin B12 Derivative and Photosensitizers, Pure Appl. Chem., DOI: 10.1351/PAC-CON-12-10-05, 85, No.7, 1415-1426, 2013.06.
85. M. Fujitsuka, Hisashi Shimakoshi, K. Noda, S. Tojo, Yoshio Hisaeda, Photoinduced Electron Transfer in Supramolecular Donor-Acceptor dyad of Zn Corrphycene, Phys. Chem. Chem. Phys., DOI: 10.1039/c3cp43795g, 15, No.15, 5677-5683, 2013.05.
86. Yoshio Hisaeda, Hisashi Shimakoshi, Kazumasa Noda, Tetsuro Majima, Bioinspired Catalytic Reactions with Vitamin B12 Derivative and Photosensitizers, Pure. Appl. Chem.,, DOI: 10.1351/PAC-CON-12-10-05, 2013.04, As part of a study directed toward design of good catalytic systems based upon a
hydrophobic vitamin B12, heptamethyl cobyrinate perchlorate, we describe the preparation of
various nanomaterials using the vitamin B12 derivative and photosensitizers. Examples
include vitamin B12-hyperbranched polymers (HBPs), human serum albumin (HSA) containing
vitamin B12 derivatives, a vitamin B12-titanium dioxide hybrid catalyst, a vitamin
B12-Ru complex combined system, and a vitamin B12-rose bengal combined system. These
bioinspired materials have the potential as catalytic systems for the degradation of organic
halide pollutants and for molecular transformations via radical intermediates during irradiation
by UV or visible light, and offer a variety of applications that are of great interest in
terms of green chemistry..
87. Yoshio Hisaeda, Hisashi Shimakoshi, Kazumasa Noda, Tetsuro Majima, Metallopolymer Films Exhibiting Three-color Electrochromism in the UV/Vis and Near-IR Region: Remarkable Utility of Trimetallic Clusters Bearing Thienyl Pendants and Their Mixed-valent Charge Transfer Transitions, Journal of Inorganic and Organometallic Polymers and Materials, DOI: 10.1007/s10904-012-9758-9, 2013.04, ANovel oxo-centered, acetate-bridged trinuclear
ruthenium clusters functionalized with two pyridine ligands
with thienyl substituents, [Ru3O(CH3COO)6(CO)(L1)2]
(1) and [Ru3O(CH3COO)6(CO)(L2)2] (2), where L1 =
4-(2-thienyl)pyridine and L2 = 4-(2,20-bithienyl)pyridine,
have been synthesized and characterized. The molecular
structure of 2 has been determined by single-crystal X-ray
diffraction. One-electron oxidation of 2 with silver(I) cation
has led to the isolation of a CO-dissociated product,
[Ru3O(CH3COO)6(H2O)(L2)2]PF6 (3!PF6), and subsequent
reaction with 4-dimethylaminopyridine (dmap) gave
[Ru3O(CH3COO)6(dmap)(L2)2]PF6 (4!PF6). Linear metallopolymers
containing the {Ru3O(CH3COO)6} groups have
been deposited onto indium-tin oxide surface via oxidative
electropolymerization of 2, 3!PF6, and 4!PF6. These metallopolymer
thin films exhibit three-color electrochromism
in the UV/Vis and near-IR region associated with the
Ru3
II,III,III, Ru3
III,III,III, and Ru3
III,III,IV oxidation states..
88. K.Tahara, A.Matsuzaki, R.Masuko, J.Kikuchi, Yoshio Hisaeda, Synthesis, Characterization, Co-S Bond Reactivity of a Vitamin B12 Model Complex Having Pentafluorophenylthiolate as an Axial Ligand, Dalton Trans., DOI: 10.1039/C3DT00042G, 42, No.18, 6410-6416, 2013.04.
89. Mamoru Fujitsuka, Hisashi Shimakoshi, Yui Tei, Kazumasa Noda, Sachiko Tojo, Yoshio Hisaeda, Tetsuro Majima, Photoinduced electron transfer in supramolecular donor-acceptor dyads of Zn corrphycene, Physical Chemistry Chemical Physics, 10.1039/c3cp43795g, 15, 15, 5677-5683, 2013.04, [URL], Porphyrins have been used by various researchers as important building blocks of photofunctional molecules, while the number of studies on the excitation properties of the structural isomers of porphyrins is small when compared to those of porphyrins. In the present study, photoinduced electron transfer (ET) processes of supramolecular donor-acceptor dyads of 2,3,6,7,11,12,17,18-octaethylcorrphycenatozinc (ZnCn), one of the porphyrin isomers, and some imide compounds, which can coordinate to the central Zn ion as an electron acceptor, were investigated. Formation of the supramolecular donor-acceptor dyads was confirmed by steady state absorption change. Charge separation and charge recombination processes upon photoexcitation of ZnCn of the supramolecular dyads were successfully observed by subpicosecond laser flash photolysis. The estimated ET rates (kET) were compared with those of other porphyrin isomers. Differences in the driving force dependence of k ET values of porphyrin isomers were attributed to the electronic coupling and internal reorganization energy. Electronic and structural factors, which brought about the difference in kET values, were reasonably explained on the basis of the theoretical calculation..
90. Yoshio Hisaeda, Keishiro Tahara, Kumiko Mikuriya, Takahiro Masuko, Junichi kikuchi, Dechlorination of DDT catalyzed by visible-light-driven system composed of vitamin B12 derivative and Rhodamine B, J. Porphyrins Phthalocyanines, 17, No. 01n02, 135-141 (2013)., DOI: 10.1142/S1088424612501398, 2013.03, The visible-light-driven dechlorination of 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane
(DDT) was carried out in the presence of a hydrophobic vitamin B12, heptamethyl cobyrinate
perchlorate and Rhodamine B. DDT was successfully dechlorinated to form 1,1-bis(4-chlorophenyl)-
2,2-dichloroethane (DDD) as the mono-dechlorinated product upon visible light irradiation with a
tungsten lamp (l > 440 nm). Upon prolonged visible light irradiation to DDT, DDMU (1-chloro-2,2-
bis(4-chlorophenyl)ethylene), DDMS (1-chloro-2,2-bis(4-chlorophenyl)ethane) and DCS (trans-4,4′-
dichlorostilbene) were obtained as the di- and tri-dechlorinated products. The use of the photostable
organic sensitizer enabled prolonged photocatalysis via a noble-metal-free process. The vitamin B12
derivative was replaced by an imine/oxime-type cobalt complex although the cobalt complex system
showed a lower catalytic activity than the B12 derivative system. The dechlorination mechanism in the
B12-Rhodamin B system was investigated by various methods such as UV-vis absorption and fluorescence
quenching.
.
91. Yoshio Hisaeda, Keishiro Tahara, Ayaka Matsuzaki, Yoshio Hisaeda, Synthesis, Characterization, Co-S Bond Reactivity of a Vitamin B12 Model Complex Having Pentafluorophenylthiolate as an Axial Ligand, Dalton Trans., 42, No.18, 6410-6416 (2013)., DOI: 10.1039/C3DT00042G, 2013.03, Heptamethyl (aquo)(pentafluorophenylthiolate)cobyrinate perchlorate, [(H2O)(C6F5S)Cob(III)7C1ester]-
ClO4, was synthesized as a B12 model complex having a thiolate ligand in the axial position. The axial
ligand change in heptamethyl (diaquo)cobyrinate diperchlorate, [(H2O)2Cob(III)7C1ester](ClO4)2, from
H2O to C6F5S− afforded the B12–thiolate complex. The B12–thiolate model complex was characterized by
UV-vis, NMR and ESI-mass spectroscopies. The coordination of C6F5S− to the cobalt center affected the
spectroscopic properties of the corrin ring through the electronic interaction between the axial ligand
(C6F5S−) and the equatorial ligand (corrin). The photolysis of the B12–thiolate model complex led to the
homolytic cleavage of the Co(III)–S bond to form the Co(II) complex and the phenyl thiyl radical. The
thermolysis of the B12–thiolate model complex also led to the homolytic cleavage of the Co(III)–S bond.
Furthermore, the reactivity of the Co(III)–S bond of the B12–thiolate model complex was applied to the
catalytic oxidation of C6F5SH to C6F5S–SC6F5..
92. Yoshio Hisaeda, Hisashi Shimakoshi, Kazumasa Noda, Tetsuro Majima, Photoinduced Electron Transfer in Supramolecular Donor-Acceptor dyad of Zn Corrphycene, Phys. Chem. Chem. Phys., 15, No.15, 5677-5683 (2013)., DOI: 10.1039/c3cp43795g, 2013.03, Porphyrins have been used by various researchers as important building blocks of photofunctional
molecules, while the number of studies on the excitation properties of the structural isomers of
porphyrins is small when compared to those of porphyrins. In the present study, photoinduced electron
transfer (ET) processes of supramolecular donor–acceptor dyads of 2,3,6,7,11,12,17,18-
octaethylcorrphycenatozinc (ZnCn), one of the porphyrin isomers, and some imide compounds, which
can coordinate to the central Zn ion as an electron acceptor, were investigated. Formation of the
supramolecular donor–acceptor dyads was confirmed by steady state absorption change. Charge
separation and charge recombination processes upon photoexcitation of ZnCn of the supramolecular
dyads were successfully observed by subpicosecond laser flash photolysis. The estimated ET rates (kET)
were compared with those of other porphyrin isomers. Differences in the driving force dependence of
kET values of porphyrin isomers were attributed to the electronic coupling and internal reorganization
energy. Electronic and structural factors, which brought about the difference in kET values, were
reasonably explained on the basis of the theoretical calculation..
93. Toru Okawara, Masaaki Abe, Hisashi Shimakoshi, Yoshio Hisaeda, A Pd(II)-hydroxyporphycene
Synthesis, characterization, and photoinduced proton-coupled electron transfer, Research on Chemical Intermediates, 10.1007/s11164-012-0640-8, 39, 1, 161-176, 2013.01, [URL], A Pd(II) complex, Pd(TPrPc-OH) (1, TPrPc-OH = 9-hydroxy-2,7,12,17- tetrapropylporphycenato dianion), has been synthesized and characterized. 1H NMR spectroscopy revealed that compound 1 exists as its enol form in solution. The H atom of the hydroxy group in 1 was exchanged with deuterium on addition of ethanol-d 6. UV-visible spectra showed a red shift of the Q band of 1 in THF compared with that of the acetoxy derivative Pd(TPrPc-OAc) (2, TPrPc-OAc = 9-acetoxy-2,7,12,17-tetrapropylporphycenato dianion). The pK a value of the hydroxy group in 1 was determined, by means of a UV-visible titration experiment, to be 10.56. A cyclic voltammogram of 1 in a mixture of THF and Britton-Robinson buffered aqueous solution revealed one-electron and one-proton coupled transfer in the oxidation process in the pH range from 2.7 to 10.5, which was identified by pH-varying experiments and the Pourbaix diagram. Transient absorption spectroscopy revealed that an electron-transfer reaction occurred from the triplet excited-state of 1 to 2,3,5,6-tetramethyl-1,4-benzoquinone (duroquinone, DQ) upon pulse laser irradiation at 532 nm. Such an intermolecular photoinduced electron-transfer reaction was not observed between the Ni analog, Ni(TPrPc-OH), and DQ. The reaction rate constant, k q, was indicative of a kinetic isotope effect with k q(H)/k q(D) = 1.7, supporting the belief that the exited-state electron transfer from 1 to DQ is accompanied by proton transfer..
94. Keishiro Tahara, Kumiko Mikuriya, Takahiro Masuko, Jun Ichi Kikuchi, Yoshio Hisaeda, Dechlorination of DDT catalyzed by visible-light-driven system composed of vitamin B12 derivative and Rhodamine B, Journal of Porphyrins and Phthalocyanines, 10.1142/S1088424612501398, 17, 1-2, 135-141, 2013.01, [URL], The visible-light-driven dechlorination of 1,1-bis(4-chlorophenyl)-2,2,2- trichloroethane (DDT) was carried out in the presence of a hydrophobic vitamin B12, heptamethyl cobyrinate perchlorate and Rhodamine B. DDT was successfully dechlorinated to form 1,1-bis(4-chlorophenyl)-2,2-dichloroethane (DDD) as the mono-dechlorinated product upon visible light irradiation with a tungsten lamp (λ > 440 nm). Upon prolonged visible light irradiation to DDT, DDMU (1-chloro-2,2-bis(4-chlorophenyl)ethylene), DDMS (1-chloro-2,2-bis(4-chlorophenyl)ethane) and DCS (trans-4,4′- dichlorostilbene) were obtained as the di- and tri-dechlorinated products. The use of the photostable organic sensitizer enabled prolonged photocatalysis via a noble-metal-free process. The vitamin B12 derivative was replaced by an imine/oxime-type cobalt complex although the cobalt complex system showed a lower catalytic activity than the B12 derivative system. The dechlorination mechanism in the B12-Rhodamin B system was investigated by various methods such as UV-vis absorption and fluorescence quenching..
95. Rumiko Matsuse, Masaaki Abe, Yuki Tomiyasu, Atsushi Inatomi, Hiroaki Yonemura, Sunao Yamada, Yoshio Hisaeda, Metallopolymer Films Exhibiting Three-Color Electrochromism in the UV/Vis and Near-IR Region
Remarkable Utility of Trimetallic Clusters Bearing Thienyl Pendants and Their Mixed-Valent Charge Transfer Transitions, Journal of Inorganic and Organometallic Polymers and Materials, 10.1007/s10904-012-9758-9, 23, 1, 136-146, 2013.01, [URL], Novel oxo-centered, acetate-bridged trinuclear ruthenium clusters functionalized with two pyridine ligands with thienyl substituents, [Ru3O(CH3COO)6(CO)(L1)2] (1) and [Ru3O(CH3COO)6(CO)(L2)2] (2), where L1 = 4-(2-thienyl)pyridine and L2 = 4-(2,2′-bithienyl)pyridine, have been synthesized and characterized. The molecular structure of 2 has been determined by single-crystal X-ray diffraction. One-electron oxidation of 2 with silver(I) cation has led to the isolation of a CO-dissociated product, [Ru3O(CH3COO)6(H2O)(L2)2]PF6 (3·PF6), and subsequent reaction with 4-dimethylaminopyridine (dmap) gave [Ru3O(CH3COO)6(dmap)(L2)2]PF6 (4·PF6). Linear metallopolymers containing the {Ru3O(CH3COO)6} groups have been deposited onto indium-tin oxide surface via oxidative electropolymerization of 2, 3·PF6, and 4·PF6. These metallopolymer thin films exhibit three-color electrochromism in the UV/Vis and near-IR region associated with the Ru3
II,III,III, Ru3
III,III,III, and Ru3
III,III,IV oxidation states..
96. Atsushi Inatomi, Masaaki Abe, Yoshio Hisaeda, Oxo-centred trimetallic clusters supported by electron-withdrawing carboxylates
Highly inert character in ligand exchange kinetics of the dichloroacetate-bridged complex [Ru33-O)(μ- CHCl2COO)6(pyridine)3], Australian Journal of Chemistry, 10.1071/CH12378, 65, 12, 1599-1607, 2012.12, [URL], Two new oxo-centred trinuclear ruthenium clusters supported by six dichloroacetate ligands, [Ru33-O)(μ-CHCl 2COO)6(CH3OH)3]CHCl2COO (1) and [Ru33-O)(μ-CHCl2COO)6(pyridine) 3] (2), have been synthesised and characterised by spectroscopic methods, electrospray ionisation mass spectrometry, single-crystal X-ray diffraction, and cyclic voltammetry. Due to the strong inductive effect of the dichloroacetate ligands, the redox potential of 2 was shifted to the positive side (∼1.0V or more) relative to the acetate analogue [Ru33-O) (μ-CH3COO)6(pyridine)3], and also the rate of pyridine/pyridine-d5 exchange reaction of 2 in CD3CN was retarded with the rate constant of kex298K=1. 9×10-8s-1 which is 105-fold smaller than the value for [Ru33-O)(μ-CH3COO) 6(pyridine)3]. Highly positive activation parameters obtained for 2, ΔH=138±7kJmol-1 and ΔS=71±20JK-1mol-1, illustrate a dissociative activation pathway in which rupture of the Ru-N(pyridine) bond is involved in the rate-determining step..
97. T. Okawara, M. Abe, H. Shimakoshi, Y. Hisaeda, A Pd(II)-hydroxyporphycene: synthesis, characterization, and photoinduced proton-coupled electron transfer, Res. Chem. Intermed., DOI: 10.1007/s11164-012-0640-8, 2012.10, A Pd(II) complex, Pd(TPrPc-OH) (1, TPrPc-OH = 9-hydroxy-2,7,12,17-tetrapropylporphycenato dianion), has been synthesized and characterized. 1H NMR spectroscopy revealed that compound 1 exists as its enol form in solution. The H atom of the hydroxy group in 1 was exchanged with deuterium on addition of ethanol-d6. UV–visible spectra showed a red shift of theQband of 1 in THF compared with that of
the acetoxy derivative Pd(TPrPc-OAc) (2, TPrPc-OAc = 9-acetoxy-2,7,12,17-tetrapropylporphycenato dianion). The pKa value of the hydroxy group in 1 was determined, by means of a UV–visible titration experiment, to be 10.56. A cyclic voltammogram of 1 in a mixture of THF and Britton–Robinson buffered aqueous solution revealed one-electron and one-proton coupled transfer in the oxidation process
in the pH range from 2.7 to 10.5, which was identified by pH-varying experiments and the Pourbaix diagram. Transient absorption spectroscopy revealed that an electron-transfer reaction occurred from the triplet excited-state of 1 to 2,3,5,6-tetramethyl-1,4-benzoquinone (duroquinone, DQ) upon pulse laser irradiation at 532 nm. Such an intermolecular photoinduced electron-transfer reaction was not observed
between the Ni analog, Ni(TPrPc-OH), and DQ. The reaction rate constant, kq, was indicative of a kinetic isotope effect with kq(H)/kq(D) = 1.7, supporting the belief that the exited-state electron transfer from 1 to DQ is accompanied by proton transfer..
98. R. Matsuse, M. Abe, Y. Tomiyasu, A. Inatomi, H. Yonemura, S. Yamada, Y. Hisaeda, Metallopolymer Films Exhibiting Three-color Electrochromism in the UV/Vis and Near-IR Region: Remarkable Utility of Trimetallic Clusters Bearing Thienyl Pendants and Their Mixed-valent Charge Transfer Transitions, Journal of Inorganic and Organometallic Polymers and Materials, DOI: 10.1007/s10904-012-9758-9, 2012.10, Novel oxo-centered, acetate-bridged trinuclear ruthenium clusters functionalized with two pyridine ligands with thienyl substituents, [Ru3O(CH3COO)6(CO)(L1)2] (1) and [Ru3O(CH3COO)6(CO)(L2)2] (2), where L1 = 4-(2-thienyl)pyridine and L2 = 4-(2,20-bithienyl)pyridine,
have been synthesized and characterized. The molecular structure of 2 has been determined by single-crystal X-ray diffraction. One-electron oxidation of 2 with silver(I) cation has led to the isolation of a CO-dissociated product, [Ru3O(CH3COO)6(H2O)(L2)2]PF6 (3!PF6), and subsequent reaction with 4-dimethylaminopyridine (dmap) gave [Ru3O(CH3COO)6(dmap)(L2)2]PF6 (4!PF6). Linear metallopolymers containing the {Ru3O(CH3COO)6} groups have been deposited onto indium-tin oxide surface via oxidative electropolymerization of 2, 3!PF6, and 4!PF6. These metallopolymer thin films exhibit three-color electrochromism in the UV/Vis and near-IR region associated with the Ru3 II,III,III, Ru3 III,III,III, and Ru3 III,III,IV oxidation states..
99. Keith ó Proinsias, Daniel Gryko, Yoshio Hisaeda, Emil Martin, Jonathan Sessler, Dorota Gryko, Vitamin B12 derivatives as activators of soluble guanylyl cyclase, Journal of Medicinal Chemistry, DOI: 10.1021/jm3006959, 2012.10, Various newly prepared and previously known vitamin B12 derivatives have been studied as potential soluble guanylyl cyclase (sGC) activators. All compounds tested were found to activate the sGC enzyme, although to differing extents. The best results were obtained with the derivatives synthesized from c-lactone and possessing aliphatic amides in the c- and d-positions..
100. Yoshio Hisaeda, Masaaki Abe, Atsushi Inatomi, Oxo-centered Trimetallic Clusters Supported by Electron-withdrawing Carboxylates: Highly Inert Character in Ligand Exchange Kinetics of Dichloroacetate-bridged Complex [Ru3(μ3-O)(μ-CHCl2COO)6(pyridine)3], Aust. J. Chem., No.65, 1599-1607 (2012)., http://dx.doi.org/10.1071/CH12378, 2012.10, Two new oxo-centred trinuclear ruthenium clusters supported by six dichloroacetate ligands, [Ru3(m3-O)(m-CHCl2COO)6
(CH3OH)3]CHCl2COO (1) and [Ru3(m3-O)(m-CHCl2COO)6(pyridine)3] (2), have been synthesised and characterised by
spectroscopic methods, electrospray ionisation mass spectrometry, single-crystal X-ray diffraction, and cyclic voltammetry.
Due to the strong inductive effect of the dichloroacetate ligands, the redox potential of 2 was shifted to the positive
side (,1.0V or more) relative to the acetate analogue [Ru3(m3-O)(m-CH3COO)6(pyridine)3], and also the rate of pyridine/
pyridine-d5 exchange reaction of 2 in CD3CN was retarded with the rate constant of kex
298K¼1.910
8 s
1 which is
105-fold smaller than the value for [Ru3(m3-O)(m-CH3COO)6(pyridine)3]. Highly positive activation parameters obtained
for 2, DH
z¼1387 kJ mol
1 and DS
z¼7120 JK
1 mol
1, illustrate a dissociative activation pathway in which
rupture of the Ru–N(pyridine) bond is involved in the rate-determining step..
101. Ó Proinsias Keith, Daniel T. Gryko, Yoshio Hisaeda, Emil Martin, Jonathan L. Sessler, Dorota Gryko, Vitamin B 12 derivatives as activators of soluble guanylyl cyclase, Journal of Medicinal Chemistry, 10.1021/jm3006959, 55, 20, 8943-8947, 2012.10, [URL], Various newly prepared and previously known vitamin B 12 derivatives have been studied as potential soluble guanylyl cyclase (sGC) activators. All compounds tested were found to activate the sGC enzyme, although to differing extents. The best results were obtained with the derivatives synthesized from c-lactone and possessing aliphatic amides in the c- and d-positions..
102. H. Shimakoshi, K. Sasaki, Y. Iseki, Y. Hisaeda, Synthesis and photosensitizing properties of porphycene with imidazolium tag, J. Porphyrins Phthalocyanines, 16, 530-536 (2012)., DOI: 10.1142/S1088424612500551, 16, 530-536, 2012.07, Porphycene having an imidazolium cation tag was synthesized and characterized by elemental analysis, UV-vis, NMR and ESI-mass spectroscopies. This porphycene derivative easily dissolves in various ionic liquids and produces singlet oxygen under irradiation by visible light (λ ≥460 nm). The photophysical parameters of the porphycene in ionic liquids were determined and the values were compared to those in acetonitrile. Photosensitizing reactions using this new porphycene for the oxidation of 1,5-dihydroxynaphthalene in ionic liquids were investigated and found to form 5-hydroxy-1,4-naphthoquinone. The recycled use of the porphycene was efficiently achieved in N,N,Ntrimethyl-
N-propylammonium bis(trifluoromethanesulfonyl)amide ([TMPA][TFSA]) and N-methyl-Npropylpiperidinium bis(trifluoromethanesulfonyl)amide ([P13][TFSA])..
103. T. Okawara, K. Hashimoto, M. Abe, H. Shimakoshi, Y. Hisaeda, Hydrogenation effects in metalloporphycenes: synthesis and redox behavior of Ni(II)–tetra(n-propyl)dihydroporphycene, Chem. Commun. (Inside Front Cover), DOI:10.1039/C2CC30991B, 48, 44, 5413-5415, 2012.06, 生体関連色素であるポルフィリンの構造異性体であるポルフィセンの金属錯体は、金属の還元より配位子の還元が優先して起こるという性質をもつ。本研究では、ポルフィセン配位子の還元により、中心金属の還元が可能になることを示した成果であり、触媒反応への応用が期待できる。
2,3-Dihydro-2,7,12,17-tetrapropylporphycene (1) and its NiII complex (2) have been synthesized and characterized. One-electron reduction of 2 gives a mixture of “ring-reduced” and “metal-reduced” monoanionic species, in which the latter is a prerequisite for electrocatalytic dehalogenation of organic halides..
104. Toru Okawara, Koichi Hashimoto, Masaaki Abe, Hisashi Shimakoshi, Yoshio Hisaeda, Hydrogenation effects in metalloporphycenes
Synthesis and redox behavior of Ni(ii)-tetra(n-propyl)dihydroporphycene, Chemical Communications, 10.1039/c2cc30991b, 48, 44, 5413-5415, 2012.06, [URL], Hydrogenated tetrapropylporphycenes, 2,3-dihydro-2,7,12,17- tetrapropylporphycene 1 and its Ni II complex 2, have been prepared and the hydrogenation effects on their electronic structure characterized. A one-electron reduction of 2 promotes dehalogenation of organic halides whose observation is unprecedented for the porphycene compounds..
105. Hisashi Shimakoshi, Yoshio Hisaeda, Synthesis of cyclic and acyclic Schiff-base compounds and development of unique dicobalt complexes with supramolecular functions, Yuki Gosei Kagaku Kyokaishi/Journal of Synthetic Organic Chemistry, 10.5059/yukigoseikyokaishi.70.60, 70, 1, 60-70, 2012.02, [URL], Schiff-base is a useful tool for construction of a variety of functional compounds owing to its synthetic utility and versatility. Desired cyclic and acyclic Schiff base compounds were selectively obtained in appropriate condition. Coordination sphere provided by Schiff base compound is suitable for metal ion binding to form mono-and di-nuclear metal complexes. Unique properties of dicobalt complexes with Schiff-base ligand were developed in this study. Supramolecular functions of dicobalt complexes based on reversible redox change of metal centers accompanied with structural switching were reported. Furthermore, unique catalysis of dialkylated cobalt complex such as carbon-carbon bond formation and DNA scission were described..
106. T. Okawara, J. Feng, M. Abe, Y. Hisaeda, Aquabis(1,1,1,5,5,5-hexafluoroacetylacetonato) [4'-(4-pyridyl)-2,2':6',2''-terpyridine]ytterbium(III) chloride methanol monosolvate monohydrate, Acta Cryst. E, 68, m29-m30 (2012)., 68, m29-m30, 2012.01.
107. Toru Okawara, Jiang Feng, Masaaki Abe, Yoshio Hisaeda, Aquabis(1,1,1,5,5,5-hexafluoroacetylacetonato)[4-(4-pyridyl)-2,2':6',2'' - Terpyridine]ytterbium(III) chloride methanol monosolvate monohydrate, Acta Crystallographica Section E: Structure Reports Online, 10.1107/S1600536811052378, 68, 1, 2012.01, [URL], The title compound, [Yb(C 5HF 6O 2) 2(C 20H 14N 4)(H 2O)] Cl·-CH 3OH·H 2O, adopts an eight-coordinated geometry around the Yb III atom consisting of a 4'-(4-pyridyl)-2,2': 6',2''-terpyridine (pytpy) ligand, two 1,1,1,5,5,5-hexafluoroacetylacetonate (hfac) anions and an aqua ligand. In the solid state, the compound forms supramolecular chains running along the baxis via intermolecular hydrogen bonds between the Yb-OH 2 unit and the N-atom donor of the 4-pyridyl pendant of pytpy, with an O ··· N distance of 2.686(4) Å. A chloride counter-anion and lattice methanol and water solvent molecules occupy a hydrophilic columnar space along the coordination chains. O-H ··· Cl hydrogen bonds occur. The two water molecules and the four trifluoromethyl groups are disordered over two sets of sites, each with different occupancy ratios..
108. Hisashi Shimakoshi, Kenichi Sasaki, Yusuke Iseki, Yoshio Hisaeda, Synthesis and photosensitizing properties of porphycene with imidazolium tag, Journal of Porphyrins and Phthalocyanines, 10.1142/S1088424612500551, 16, 5-6, 530-536, 2012.01, [URL], Porphycene having an imidazolium cation tag was synthesized and characterized by elemental analysis, UV-vis, NMR and ESI-mass spectroscopies. This porphycene derivative easily dissolves in various ionic liquids and produces singlet oxygen under irradiation by visible light (λ < 460 nm). The photophysical parameters of the porphycene in ionic liquids were determined and the values were compared to those in acetonitrile. Photosensitizing reactions using this new porphycene for the oxidation of 1,5-dihydroxynaphthalene in ionic liquids were investigated and found to form 5-hydroxy-1,4-naphthoquinone. The recycled use of the porphycene was efficiently achieved in N,N,N-trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)amide ([TMPA][TFSA]) and N-methyl-N-propyl-piperidinium bis(trifluoromethanesulfonyl) amide ([P13][TFSA])..
109. Hisashi Shimakoshi, Li Li, Masashi Nishi, Yoshio Hisaeda, Photosensitizing catalysis of the B12 complex without an additional photosensitizer, Chemical Communications, 10.1039/c1cc12482j, 47, 39, 10921-10923, 2011.10, [URL], A cobalamin derivative, heptamethyl cobyrinate perchlorate, was activated by UV light irradiation to form a Co(i) species in the presence of triethanolamine and used for a dechlorination reaction, and this photochemical reaction was accelerated in an ionic liquid..
110. H. Shimakoshi, L. Li, M. Nishi, Y. Hisaeda, Photosensitizing catalysis of B12 complex without additional photosensitizer, Chem. Commun. (Back Cover), 47, 39, 10921-10923, 2011.09, ビタミンB12が光増感作用を示すことを世界で初めて発見しました。従来は光増感剤共存下で進行していた光駆動型ビタミンB12反応を、ビタミンB12単独で進行させることに成功し、環境汚染物質であるDDTの脱塩素化反応応用しました。英国王立化学会Chem. Commun.誌のBack coverを飾りました。

  A cobalamin derivative, heptamethyl cobrinate perchlorate, was activated by UV light irradiation to form a Co(I) species in the presence of triethanolamine and used for a dechlorination reaction, and this photochemical reaction was accelerated in an ionic liquid..
111. T. Okawara, M. Abe, H. Shimakoshi, Y. Hisaeda, Hydroxy-Functionalized Porphycenes: Structure, Spectroscopy, and Electrochemistry, Bull. Chem. Soc. Jpn.(Selected Paper), 84, 7, 718-728, 2011.07.
112. Toru Okawara, Masaaki Abe, Hisashi Shimakoshi, Yoshio Hisaeda, Hydroxy-functionalized porphycenes
Structure, spectroscopy, and electrochemistry, Bulletin of the Chemical Society of Japan, 10.1246/bcsj.20110072, 84, 7, 718-728, 2011.07, [URL], A series of porphycenes bearing acetoxy and hydroxy groups at the meso-positions have been prepared and fully characterized: H2TPrPc- OH, [Ni(TPrPc-OH)], H2TPrPc-OAc, and [Ni(TPrPc-OAc)], where TPrPc-OH: 9-hydroxy- 2,7,12,17-tetrapropylporphycenato dianion and TPrPc-OAc: 9-acetoxy-2,7,12,17-tetrapropylporphycenato dianion. H2TPrPc-OH is structurally determined by single-crystal X-ray diffraction, showing the enol-form in the solid state. The introduction of the electron-donating hydroxy group to the meso-position decreases the HOMOLUMO gap by ca. 0.2 eV relative to the unsubstituted parent porphycene due to the remarkable destabilization of the HOMO level. This is experimentally confirmed by red shift of the Q band in the UVvis spectra (in CH2Cl2), negative shift of the E 1/2 (in 0.1M n-Bu4NPF6THF), and also supported by DFT calculations. In aqueous THF, an irreversible oxidation of H 2TPrPc-OH and [Ni(TPrPc-OH)] appears to be pH-dependent, with a negative Epa shift upon increasing the solution pH (in the region from 3.0 to 10.5) with slopes of -62 and -63mV per pH unit for H 2TPrPc-OH and [Ni(TPrPc-OH)], respectively, indicating the occurrence of {1H+/1e} proton-coupled electron transfer..
113. Hisashi Shimakoshi, Masashi Nishi, Akihiro Tanaka, Katsumi Chikama, Yoshio Hisaeda, Photocatalytic function of a polymer-supported B12 complex with a ruthenium trisbipyridine photosensitizer, Chemical Communications, 10.1039/c1cc11970b, 47, 23, 6548-6550, 2011.06, [URL], The hybrid polymer was synthesized by a radical polymerization of a B 12 derivative and a Ru complex having styrene moieties in each peripheral position, and the hybrid polymer showed photocatalytic activity for molecular transformation with visible light irradiation..
114. M. Abe, A. Inatomi, Y. Hisaeda, Electroactive Chain-like Compounds Constructed from Trimetallic Clusters and 4,4’-Bipyridine Spacers: One-pot Synthesis, Characterization and Surface Binding, Dalton Trans., 40, 10, 2289-2298, 2011.05.
115. H. Shimakoshi, M. Nishi, A. Tanaka, K. Chikama, Y. Hisaeda, Photocatalytic function of polymer-supported B12 complex with ruthenium trisbipyridine photosensitizer, Chem. Commun.(Inside Front Cover), 47, 23, 6548-6550, 2011.05, 可視光増感作用を示すルテニウム錯体と天然酵素のモデル化合物であるビタミンB12を共重合させたハイブリッドポリマーを作製しました。本ポリマーに可視光照射することで、高効率なポリマー内電子移動が起こり、ビタミンB12触媒反応を行うことが出来ました。

  The hybrid polymer was synthesized by a radical polymerization of a B12 derivative and a Ru complex having styrene moieties in each peripheral position, and the hybrid polymer showed photocatalytic activity for molecular transformation with visible light irradiation..
116. H. Shimakoshi, D. Maeda, Y. Hisaeda, Supramolecular Assemblies of Crown-substituted Dinickel and Dicobalt Complexes with Guest Cation Binding, Supramol. Chem., 23, 1-2, 131-139, 2011.04.
117. K. Tahara, Y. Hisaeda, Eco-friendly Molecular Transformations Catalyzed by Vitamin B12 Derivative with Visible-Light-Driven System, Green Chem., 13, 3, 558-561, 2011.04.
118. L. Pan, K. Tahara, T. Masuko, Y. Hisaeda, Methyl-transfer Reaction to Alkylthiol Catalyzed by a Simple Vitamin B12 Model Complex Using Zinc Powder, Inorg. Chim. Acta, 368, 1, 194-199, 2011.03.
119. Keishiro Tahara, Yoshio Hisaeda, Eco-friendly molecular transformations catalyzed by a vitamin B 12 derivative with a visible-light-driven system, Green Chemistry, 10.1039/c0gc00478b, 13, 3, 558-561, 2011.03, [URL], A new bio-inspired system composed of a vitamin B12 derivative and Rose Bengal, catalyzed the dehalogenations of various toxic alkyl halides such as 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) via a noble-metal-free and visible-light-driven process. This system also catalyzed radical-involved organic reactions such as the 1,2-migration of acyl group via a tin-free process..
120. Masaaki Abe, Atsushi Inatomi, Yoshio Hisaeda, Electroactive chain-like compounds constructed from trimetallic clusters and 4,4′-bipyridine spacers
One-pot synthesis, characterization and surface binding, Dalton Transactions, 10.1039/c0dt01237h, 40, 10, 2289-2298, 2011.03, [URL], This paper reports the synthesis and characterization of a novel series of chain-like compounds where oxo-centered triruthenium cluster moieties are bridged by 4,4′-bipyridine (4,4′-bpy) spacers. A reaction of solvent-coordinated triruthenium "monomer" precursor [Ru 3O(CH3CO2)6(CO)(CH 3OH)2] with a 0.1 equimolar amount of 4,4′-bpy in CH3OH gave mixture of chain-like compounds containing "dimers" to "tetramers" which were cleanly separated by column chromatography and characterized by spectroscopic and electrochemical methods. Cyclic voltammetry revealed that all chain-like compounds exhibit reversible and stepwise redox processes in solution with very weak intramolecular coupling between the triruthenium components across the 4,4′-bpy bridge. Photo-induced dissociation of CO from the compounds and electrode surface binding were also investigated..
121. Ling Pan, Keishiro Tahara, Takahiro Masuko, Yoshio Hisaeda, Methyl-transfer reaction to alkylthiol catalyzed by a simple vitamin B 12 model complex using zinc powder, Inorganica Chimica Acta, 10.1016/j.ica.2011.01.004, 368, 1, 194-199, 2011.03, [URL], The catalytic methyl-transfer reaction from methyl tosylate to 1-octanethiol was carried out in the presence of a simple vitamin B12 model complex, [Co(III){(C2C3)(DO)(DOH)pn}Br 2], with zinc powder as the reducing reagent at 50°C. Such a catalytic reaction proceeded via the formation and dissociation of a cobalt-carbon bond in the simple vitamin B12 model complex under non-enzymatic conditions. The mechanism for the methyl-transfer reaction was investigated by electronic and mass spectroscopies. The Co(I) species, which is generated from the reduction of the catalyst by the zinc powder, and its methylated CH3-Co complex were found to be indispensable intermediates..
122. K. Tahara, Y. Chen, L. Pan, T. Masuko, H. Shimakoshi, Y. Hisaeda, Electrochemical Catalytic Carbon-Skeleton Rearrangement Reaction Mediated by Imine/Oxime-Type B12 Model Complex, Chem. Lett.(Editor’s Choice), 40, 2, 177-179, 2011.02.
123. Keishiro Tahara, Yi Chen, Ling Pan, Takahiro Masuko, Hisashi Shimakoshi, Yoshio Hisaeda, Electrochemical catalytic carbon-skeleton rearrangement mediated by imine/oxime-type B12 model complex, Chemistry Letters, 10.1246/cl.2011.177, 40, 2, 177-179, 2011.02, [URL], An electrochemical carbon-skeleton rearrangement of methylmalonate skeleton to succinate was successfully mediated by an imine/oxime-type cobalt complex using diethyl 2-bromomethyl-2- phenylmalonate as a model substrate of a coenzyme B12-dependent enzymatic reaction. Cyclic voltammetric and mass spectrometric studies revealed that this electrocatalysis of the alkyl bromide with 1,2-migration of a carboxylic ester group was achieved by the duet redox process between the reduction of the monoalkylated complex and the oxidation of the dialkylated complex..
124. M. Fujitsuka, H. Shimakoshi, Y. Hisaeda, T. Majima, Reorganization Energy of Supramolecular Donor-Acceptor Dyad of Octaethylporphyrin Isomers and Axial-Coordinated Acceptor: Experimental and Computational Study, J. Photochem. Photobiol. A., 217, 1, 242-248, 2011.01.
125. Mamoru Fujitsuka, Hisashi Shimakoshi, Yoshio Hisaeda, Tetsuro Majima, Reorganization energy of supramolecular donor-acceptor dyad of octaethylporphyrin isomers and axial-coordinated acceptor
Experimental and computational study, Journal of Photochemistry and Photobiology A: Chemistry, 10.1016/j.jphotochem.2010.10.016, 217, 1, 242-248, 2011.01, [URL], The internal reorganization energy (λV) of photoinduced electron transfer (ET) in the supramolecular donor-acceptor dyads of 2,3,7,8,12,13,17,18-octaethylporphinatozinc(II) (ZnOEP) and electron acceptor ligands was compared with those of structural isomers, 2,3,7,8,11,12,17,18- octaethylhemiporphycenatozinc(II) (ZnHPc) and 2,3,6,7,12,13,16,17- octaethylporphycenatozinc(II) (ZnPcn). First, ET process of the supramolecular donor-acceptor dyads of ZnOEP was investigated by means of the transient absorption spectroscopy mainly. The formation of supramolecular dyads was confirmed by absorption spectral change, from which the association constant was estimated. The ET process was confirmed by the observation of radical cation of ZnOEP during the laser flash photolysis. The ET rates of these dyads are in the order of ZnOEP > ZnHPc > ZnPcn, when the driving forces for ET are similar to each other. From the free energy dependence of ET rates, the λV values of OEP and its isomers were estimated. The estimated λV value was in the order of ZnOEP < ZnHPc < ZnPcn. This tendency was reproduced by calculation at B3LYP/6-31G(d) and BHandHLYP/6-31G(d) levels. The origin of this tendency was discussed on the basis of the structural change during the ET process..
126. Hisashi Shimakoshi, Daisuke Maeda, Yoshio Hisaeda, Supramolecular assemblies of crown-substituted dinickel and dicobalt complexes with guest cation binding, Supramolecular Chemistry, 10.1080/10610278.2010.514910, 23, 1-2, 131-139, 2011.01, [URL], A new macrocyclic ligand (L1) having four crown ether moieties at the peripheral position was synthesised by a conventional Schiff-base condensation reaction. The corresponding dinickel (1) and dicobalt (2) complexes formed a unique face-to-face dimerised structure by complexation with a Cs+ ion, which was characterised by 1H NMR, UV-vis and electrospray ionisation (ESI)-MS. Multi-sandwich structures consist of a 2:1 interaction of the benzo-18-crown-6 ether with the Cs+ ion affording a significantly high overall formation constant (Kall = 25.9 ± 0.9 at 298 K). The redox behaviour of the assembled structure of the dicobalt complex was investigated by cyclic voltammetry. In the dimerised structure, two sequential reductions ascribed to the CoIICoII/CoIICoI and CoIICoI/CoICoI couples were observed at - 1.13 V (E1) and - 1.36 V (E2) vs. Ag/AgCl, and both potentials were separated by E = E1 - E2 = 0.23 V. A mixed valence state (CoIICoI) was stabilised in the complex with the comproportionation constant Kcom = 7.7 × 103 at 298 K..
127. H. Koshima, H. Kamano, Y. Hisaeda, H. Liu, S. Ye, Analyses of the Adsorption Structures of Friction Modifiers by Means of Quantitative Structure-Property Relationship Method and Sum Frequency Generation Spectroscopy, Tribology Online, 5, 3, 165-172, 5, No.3, 165-172 (2010), 2010.09.
128. H. Shimakoshi, M. Nishi, A. Tanaka, K. Chikama, Y. Hisaeda, Synthesis and Catalysis of B12-core-shell-Hyperbranched Polymer, Chem. Lett, 39, 1, 3035-3042, 39, No.1, pp.22-23 (2010), 2010.09.
129. H. Shimakoshi, M. Abiru, K. Kuroiwa, N. Kimizuka, M. Watanabe, Y. Hisaeda, Preparation and Reactivity of B12-TiO2 Hybrid Catalyst Immobilized on Glass Plate, Bull. Chem. Soc. Jpn, 82, 2, 170-172, 82, No.2, pp.170-172 (2010), 2010.09.
130. K. Tahara, H. Shimakoshi, A. Tanaka, Y. Hisaeda, Synthesis, Characterization and Catalytic Function of B12-Hyperbranched Polymer, Dalton Trans, 39, 12, 3035-3042, 39, No.12, pp.3035-3042 (2010), 2010.09.
131. S. Izumi, H. Shimakoshi, M. Abe, Y. Hisaeda, Photo-Induced Ring-Expansion Reactions Mediated by B12-TiO2 Hybrid Catalyst, Dalton Trans, 39, 13, 3302-3307, 39, No.13, pp.3302-3307 (2010), 2010.09.
132. D. Maeda, H. Shimakoshi, M. Abe, M. Fujitsuka, T. Majima, Y. Hisaeda, Synthesis of a novel Sn(IV) porphycene-ferrocene triad linked by axial coordination and solvent polarity effect in photoinduced charge separation process, Inorg. Chem, 49, 6, 2872-2880, 49, No.6, pp.2872-2880 (2010), 2010.09.
133. A. Ikegami, M. Abe, A. Inatomi, Y. Hisaeda, Synthetic Design of Heterometallic Cluster Compounds with Site-Selective and Stepwise Substitution of Bridging Carboxylates, Chem. Eur. J, 16, 15, 4438-4441, 16, No.15, pp.4438-4441 (2010), 2010.09.
134. M. Fujitsuka, H. Shimakoshi, S. Tojo, L. Cheng, D. Maeda, Y. Hisaeda, T. Majima, Electron Transfer in the Supramolecular Donor-Acceptor Dyad of Zinc Hemiporphycene, J. Phys. Chem, 114, 12, 4156-4162, 114, No.12, pp.4156-4162 (2010), 2010.09.
135. M. Taneda, D. Maeda, H. Shimakoshi, M. Abe, Y. Hisaeda, Preparations and Photosensitizing Properties of 2,7,12,17-Tetra-n-Propylporphycenatotin(IV) Dihalide Complexes, Bull. Chem. Soc. Jpn, 82, 6, 667-671, 82, No.6, pp.667-671 (2010), 2010.09.
136. H. Koshima, H. Kamano, Y. Hisaeda, H. Liu, S. Ye, Analyses of the Adsorption Structures of Friction Modifiers by Means of Quantitative Structure-Property Relationship Method and Sum Frequency Generation Spectroscopy, Tribology Online, 5, 3, 165-172, 5, No.3, pp.165-172 (2010), 2010.09.
137. K. Tahara, H. Shimakoshi, A. Tanaka, Y. Hisaeda, Redox Behavior and Electrochemical Catalytic Function of B12-Hyperbranched Polymer, Bull. Chem. Soc. (BCSJ Award Article), 83, 12, 1439-1446, 83, No.12, pp.1439-1446 2010 (BCSJ Award Article), 2010.09, 近年、脱塩素化反応を行う菌体にビタミンB12が含まれていることが明らかとなり、脱塩素化触媒としての応用が期待されています。本研究では、機能性粒子ハイパーブランチポリマー(HBP)に着目し、これにビタミンB12誘導体を結合したB12修飾ハイパーブランチポリマー(B12-HBP)を創製し、電気化学的手法による脱塩素化反応に成功しました。柔軟な分岐骨格に沿って固定化されたB12部位は、基質や電極に対して高いアクセス性を保持し、B12-HBPは均一系触媒として優れた性質を示しました。土壌残留性農薬DDTの電気化学的脱塩素化反応に成功し、B12-HBPが環境浄化触媒として有効であることを示しました。本論文が、Bull.Chem.Soc.Jpn. BCSJ Award Articleに選ばれ、2010年12月号の表紙に掲載されました。

  The redox behavior of a covalently functionalized hyperbranched polymer with a vitamin B12 derivative (B12-HBP) was investigated by cyclic voltammetry and UV-vis spectroscopy combined with bulk electrolysis in DMF. The B12-HBP showed excellent properties for a homogeneous catalyst such as the good accessibilities of the cobalt centers in B12-HBP to an electrode and substrates and the maintained supernucleophilicity of the Co(I) species to alkyl halides. Furthermore, B12-HBP was used as an electrochemical degradation catalyst for DDT. This work presents the first electrocatalysis study of a catalytically active transition metal complex on a homogeneous dendritic support and investigates the suitability of the present B12-HBP system for electrochemical dehalogenation..
138. M. Fujitsuka, H. Shimakoshi, S. Tojo, L. Cheng, D. Maeda, Y. Hisaeda, T. Majima, Electron Transfer in the Supramolecular Donor-Acceptor Dyad of Zinc Hemiporphycene, J. Phys. Chem., A, 114, 12, 4156-4162, 114, No.12, 4156-4162 (2010), 2010.06.
139. M. Taneda, D. Maeda, H. Shimakoshi, M. Abe, Y. Hisaeda, Preparations and Photosensitizing Properties of 2,7,12,17-Tetra-n-Propylporphycenatotin(IV) Dihalide Complexes, Bull. Chem. Soc. Jpn., 82, 6, 667-671, 82, No.6, 667-671 (2010), 2010.06.
140. A. Ikegami, M. Abe, A. Inatomi, Y. Hisaeda, Synthetic Design of Heterometallic Cluster Compounds with Site-Selective and Stepwise Substitution of Bridging Carboxylates, Chem. Eur. J., 16, 15, 4438-4441, 16, No.15, 4438-4441 (2010), 2010.05.
141. S. Izumi, H. Shimakoshi, M. Abe, Y. Hisaeda, Photo-Induced Ring-Expansion Reactions Mediated by B12-TiO2 Hybrid Catalyst, Dalton Trans, 39, 13, 3302-3307, 39, No.13, 3302-3307 (2010), 2010.04.
142. D. Maeda, H. Shimakoshi, M. Abe, M. Fujitsuka, T. Majima, Y. Hisaeda, Synthesis of a novel Sn(IV) porphycene-ferrocene triad linked by axial coordination and solvent polarity effect in photoinduced charge separation process, Inorg. Chem., 49, 6, 2872-2880, 49, No.6, 2872-2880 (2010), 2010.04.
143. Mamoru Fujitsuka, Hisashi Shimakoshi, Sachiko Tojo, Lingli Cheng, Daisuke Maeda, Yoshio Hisaeda, Tetsuro Majima, Electron transfer in the supramolecular donor - acceptor dyad of zinc hemiporphycene, Journal of Physical Chemistry A, 10.1021/jp9119342, 114, 12, 4156-4162, 2010.04, [URL], In the present study, photoinduced electron transfer (ET) processes of supramolecular donor-acceptor dyads of Zn 2,3,7,8,11,12,17,18- octaethylhemiporphycene (ZnHPc) and axial ligands were investigated by using various spectroscopic methods. The formation of 1:1 dyads was confirmed by absorption spectral change during titration of axial ligand. The association constants were determined from the spectral change. Quenching of the fluorescence intensity was observed when electron acceptor ability of the axial ligand increased. The driving forces for ET were estimated based on the estimated redox potentials and structural parameters. It became clear that various ZnHPc dyads showed ET because of slightly higher donor-ability and larger excitation energy of ZnHPc when compared to the corresponding dyads of Zn porphycene (ZnPcn). The transient absorption spectra during the sub-picosecond laser flash photolysis showed the formation of charge separated state, that is, radical cation of ZnHPc and radical anion of axial ligand, from the singlet excited ZnHPc. The observed ET rates were compared with the previously reported values for Zn porphyrins and ZnPcn. The ET rates of ZnHPc were located between those observed with porphyrins and ZnPcn supramolecular dyads, even when the -AG values were similar to each other. This observation was explained on the basis of the variation in reorganization energy and electronic coupling (V) values. Furthermore, distribution of HOMO electron density gave a plausible explanation for the variation in V values of these dyads..
144. Atsushi Ikegami, Masaaki Abe, Atsushi Inatomi, Yoshio Hisaeda, Synthetic design of heterometallic cluster compounds with site-selective and stepwise substitution of bridging carboxylates, Chemistry - A European Journal, 10.1002/chem.201000387, 16, 15, 4438-4441, 2010.04, [URL], At the right places: Owing to substitution-lability difference in disparate metal centers, an oxo-centered heterometallic trinuclear acetato complex [Ru2MgO(CH3COO)6(Py)3] (py=pyridine; see picture) undergoes site-selective substitution of propionates and ferrocenycarboxylates in a stepwise manner. The new substituted families have been successfully separated by chromatography and fully characterized. (Chemical Figure Presented).
145. K. Tahara, H. Shimakoshi, A. Tanaka, Y. Hisaeda, Synthesis, Characterization and Catalytic Function of B12-Hyperbranched Polymer, Dalton Trans., 39, 12, 3035-3042, 39, No.12, 3035-3042 (2010), 2010.03.
146. Daisuke Maeda, Hisashi Shimakoshi, Masaaki Abe, Mamoru Fujitsuka, Testuro Majima, Yoshio Hisaeda, Synthesis of a novel Sn(IV) porphycene-ferrocene triad linked by axial coordination and solvent polarity effect in photoinduced charge separation process, Inorganic Chemistry, 10.1021/ic902444x, 49, 6, 2872-2880, 2010.03, [URL], A novel Sn(IV) porphycene-ferrocene triad molecule, trans- bis(ferrocenecarboxylato)(2,3,6,7,12,13,16,17-octaethylporphycenato)tin(IV), [SnIV(OEPc)(FcCOO)2] (2), was synthesized and fully characterized by various spectroscopic methods. This is the first example of a metalloporphycene triad linked by the axial coordination of two functionallzed units to a metallocenter. The steady-state fluorescence measurement indicated the efficient fluorescence quenching by coordination of the ferrocenecarboxylic acid in comparison to the corresponding dihydroxy-Sn(IV) porphycene, [Sn IV(OEPc)(OH)2] (1) ℙF = 0.094; 2, ℙF = 0.01 ). The electron transfer process from the ferrocene units to the excited Sn(IV) porphycene was directly observed by subplcosecond transient absorption spectroscopy in acetonltrile (polar solvent) and toluene (nonpolar solvent). In acetonltrile, the transient species attributed to the Sn(IV) porphycene radical anion was observed at 750 and 850 nm within 1 ps after the excitation, and then the generated charge separation state disappeared with a value of 6.9 x 10 11 s-1 for the time constant. On the other hand, the generated charge separation state decayed with two components, 3.9 x 10 11 and 9.6 x 109 s-1 time constants, in toluene. For the observed two-component decay in toluene, a significant equilibrium between the charge separation state and the triplet state was proposed because these energy levels are close to each other. Therefore, the solvent-polarity-dependent long-lived charge separation state was obtained in the Sn(IV) porphycene-ferrocene triad system. The electron transfer upon excitation of the Sn(IV) porphyrin of [SnIV(OEP)(FcCOO)2] (4), in which OEP denotes the 2,3,6,7,12,13,16,17-octaethylporphyrln ligand, was observed. However, no equilibrium between the charge separation and the triplet states was observed in both the acetonitrlle and toluene. The difference in the charge recombination processes of the Sn(IV)-porphycene and -porphyrin is due to the small HOMO-LUMO gap and the large driving force (-ΔGCs) of 2 compared to that of 4, which resulted In the energy level of the charge separation state close to the triplet state in toluene. Furthermore, the large driving force (-ΔGCs) of 2 compared to that of 4 is attributed to the significant stabilization of the LUMO energy level caused by a decrease in the molecular symmetry and a large porphycene π-electron framework. This result indicates that porphycenes are excellent candidates as an electron acceptor in photoinduced electron transfer systems..
147. H. Shimakoshi, M. Abiru, K. Kuroiwa, N. Kimizuka, M. Watanabe, Y. Hisaeda, Preparation and Reactivity of B12-TiO2 Hybrid Catalyst Immobilized on Glass Plate, Bull. Chem. Soc. Jpn., 82, 2, 170-172, 82, No.2, 170-172 (2010), 2010.02.
148. H. Shimakoshi, M. Nishi, A. Tanaka, K. Chikama, Y. Hisaeda, Synthesis and Catalysis of B12-core-shell-Hyperbranched Polymer, Chem. Lett., 39, 1, 22-23, 39, No.1, 22-23 (2010), 2010.01.
149. Shin Ichiro Izumi, Hisashi Shimakoshi, Masaaki Abe, Yoshio Hisaeda, Photo-induced ring-expansion reactions mediated by B12-TiO 2 hybrid catalyst, Dalton Transactions, 10.1039/b921802e, 39, 13, 3302-3307, 2010, [URL], Vitamin B12-TiO2 heterogeneous hybrid catalyst (B12-TiO2) mediated ring-expansion reactions and their reaction mechanism were clarified by various spectroscopic methods. Diffuse reflectance UV/VIS (DR-UV/VIS) studies showed that B12-TiO 2 was activated to form the supernucleophilic Co(i) species of B 12 by irradiation with ultraviolet light. DR-UV/VIS and electron spin resonance (ESR) studies then elucidated the formation of the photo-sensitive intermediate on heterogeneous surfaces. The photo-excited B12- TiO2 catalyzed ring-expansion reactions were efficient and eco-friendly. This catalytic efficiency was strongly dependent on the kind of solvent. The oxidation reaction of the solvent by holes at TiO2 nanoparticle surfaces had a crucial role in the overall catalytic reaction..
150. Hisashi Shimakoshi, Makoto Abiru, Keita Kuroiwa, Nobuo Kimizuka, Midori Watanabe, Yoshio Hisaeda, Preparation and reactivity of vitaminB12-TiO2 hybrid catalyst immobilized on a glass plate, Bulletin of the Chemical Society of Japan, 10.1246/bcsj.20090234, 83, 2, 170-172, 2010, [URL], The vitaminB12-TiO2 hybrid catalyst was effectively immobilized on a glass plate, and the immobilized catalyst shows an efficient reactivity for various molecular transformations, such as the 1,2-migration of a phenyl group and dechlorination of perchloroethylene during irradiation by UV light..
151. Masatsugu Taneda, Daisuke Maeda, Hisashi Shimakoshi, Masaaki Abe, Yoshio Hisaeda, Preparations and photosensitizing properties of 2,7,12,17-tetran-n- propylporphycenatotin(IV) dihalide complexes, Bulletin of the Chemical Society of Japan, 10.1246/bcsj.20100018, 83, 6, 667-671, 2010, [URL], 2,7,12,17-Tetra-n-propylporphycenatodihalotin(IV) complexes ([Sn(TPrPc)X2], X = F, Cl, and Br) were synthesized and their photophysical properties were investigated. These complexes exhibit strong absorptions in the red region (600630 nm). Strong quenching was observed during the fluorescence emission of the dibromotin(IV) complex, which is caused by an intramolecular heavy-atom effect. The complexes emit NIR phosphorescence in 1-iodopropane at room temperature and the intensity of the emission of the dibromotin(IV) complex is found to be smaller than that of the dichlorotin(IV) complex. The quantum efficiency (φδ) of generation of singlet oxygen using the dibromotin(IV) complex is the highest among the porphycenatotin(IV) complexes (φδ = 0.79). Photooxidation of 1,3-diphenylisobenzofuran catalyzed by the complexes upon irradiation with red light (over 600 nm) was studied and a rapid oxidation of the substrate was observed when using the dibromotin(IV) complex..
152. Keishiro Tahara, Hisashi Shimakoshi, Akihiro Tanaka, Yoshio Hisaeda, Redox behavior and electrochemical catalytic function of B 12hyperbranched polymer, Bulletin of the Chemical Society of Japan, 10.1246/bcsj.20100221, 83, 12, 1439-1446, 2010, [URL], The electrochemical behavior of a covalently functionalized hyperbranched polymer with a vitamin B12 derivative (B12HBP) was investigated by cyclic voltammetry and UVvis spectroscopy combined with bulk electrolysis in N,Ndimethylformamide.The B12HBP showed excellent properties for a homogeneous catalyst such as the good accessibilities of the cobalt centers in B12HBP to an electrode and substrates and the maintained supernucleophilicity of the Co(I) species to alkyl halides. The cobalt-methylated B12HBP was newly synthesized, and its electrochemical behavior was also investigated by cyclic voltammetry. Furthermore, B12HBP was used as an electrochemical degradation catalyst for 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT). This work presents the first electrocatalysis study of a catalytically active transition-metal complex on a homogeneous dendritic support and investigates the suitability of the present B12HBP system for electrochemical dehalogenation..
153. Hisashi Shimakoshi, Masashi Nishi, Akihiro Tanaka, Katsumi Chikama, Yoshio Hisaeda, Synthesis and catalysis of B12-core-shell hyperbranched polymer, Chemistry Letters, 10.1246/cl.2010.22, 39, 1, 22-23, 2010, [URL], A vitamin B12 derivative was immobilized on a core-shell hyperbranched polymer, and the hybrid polymer was characterized by GPC, UV-vis, IR as well as TEM analyses. The hybrid polymer exhibits catalysis for the dehalogenation of phenethyl bromide to form ethylbenzene and 2, 3 -diphenylbutane by irradiation with UV light at room temperature..
154. Keishiro Tahara, Hisashi Shimakoshi, Akihiro Tanaka, Yoshio Hisaeda, Synthesis, characterization and catalytic function of a B 12-hyperbranched polymer, Dalton Transactions, 10.1039/b923924c, 39, 12, 3035-3042, 2010, [URL], A new hybrid catalyst composed of a vitamin B12 derivative and a hyperbranched polymer (HBP) was synthesized and characterized by UV-vis and ESR spectroscopy as well as AFM. The B12-HBP showed good properties as a homogenous catalyst. The covalently-immobilized B12 moieties were efficiently solvated and the cobalt centers were accessible for pyridine guests. The B12-HBP showed high reactivity to 2-phenethylbromide and increased selectivity for reductive dimerization in the presence of TiO 2 with UV light irradiation..
155. Takashi MATSUO, Akihiro HAYASHI, Takaaki MATSUDA, Yoshio HISAEDA, Takashi HAYASHI, Meso-unsubstituted Iron Corrole in Hemoproteins: Remarkable Differences in Effects on Peroxidase Activities between Myoglobin and Horseradish Peroxidase, J. Am. Chem. Soc., 131, 42, 15124-15125, Vol.131, No.42, 15124-15125 (2009), 2009.12.
156. Atsushi Inatomi, Masaaki Abe, Yoshio Hisaeda, Carboxylato-Modified new oxo-Centred triruthenium cluster compounds with CO and solvent ligands
The X-ray structure of [Ru3O(C 2H5CO2)6(CO)(THF)2], European Journal of Inorganic Chemistry, 10.1002/ejic.200900701, 32, 4830-4836, 2009.12, [URL], New synthetic precursors for CO-coordinated, oxo-centred triruthenium(II,III,III) complexes with varied, carboxylato groups [Ru 3O(RCO2)6(CO)(solvent)2] where R = C2H5, CH3 and C6H5 have been prepared and characterised. Among the series, the propionato-bridged complex [Ru3O(C2H5CO2) 6(CO)(THF)2] (1) was structurally determined by single-crystal X-ray crystallography. Cyclic voltammetry revealed that the benzoato-bridged complex [Ru3O(C6H5CO 2)6(CO)(C2H5OH)2] in 0.1 mol dm-3 nBu4NPF6/DMF undergoes two consecutive one-electron processes assignable to the redox of the Ru33-O) core, the redox potentials of which are highly dependent on the electron-donating/accepting nature of the carboxylato groups. UV-light excitation of the compounds in CH3CN resulted in the dissociation of CO to form the tris(CH3CN) compounds [Ru3O(RCO 2)6(CH3CN)3] (R = C 2H5, CH3 and C6H5). These compounds are highly useful as synthetic precursors to a wide range of μ3-oxo-trirutherium derivatives with well-defined redox responses..
157. Hisashi Shimakoshi, Takeshi Kaieda, Yoshio Hisaeda, The single- and double-strand cleavage of DNA by a cationic dicobalt complex by visible light, Bulletin of the Chemical Society of Japan, 10.1246/bcsj.82.1386, 82, 11, 1386-1392, 2009.12, [URL], A one-pot synthesis of a new polycationic organodicobalt complex having dual cationic alkyl groups as radical sources is reported. The complex was characterized by elemental analysis, UVvis, 1HNMR, IR, and CSI-mass spectroscopies. CSI-MS afforded intact parent ion peak with labile cobaltcarbon bonds in the complex. The complex was photosensitive, and photocleavage of the cobaltcarbon bonds upon irradiation with visible light produced dual cationic carbon-centered radicals that were detected by EPR spin-trapping. Strong binding of the dicobalt complex with six cationic moieties toward DNA was confirmed by ethidium bromide displacement assays with Kapp = 3.2 × 10 7M-1 at 298 K, the value was 100 times that of corresponding monocobalt complex with Kapp = 3.3 × 10 5M-1. The dicobalt complex exhibited high ability for single- and double-strand DNA cleavage in comparison with that for the corresponding monocobalt complex under irradiation with visible light..
158. Hisashi SHIMAKOSHI, Takeshi KAIEDA, Yoshio HISAEDA, The Single- and Double-Strand Cleavage of DNA by a Cationic Dicobalt Complex by Visible Light, Bull. Chem. Soc. Jpn, 82, 11, 1386-1392, Vol. 82,No.11,1386-1392 (2009), 2009.11.
159. Atsushi INATOMI, Masaaki ABE, Yoshio HISAEDA, Carboxylato-Modified New Oxo-Centered Triruthenium Cluster Compounds with CO and Solvent Ligands. The X-Ray Structure of [Ru3O(C2H5CO2)6(CO)(THF)2], Eur. J. Inorg. Chem, 32, 4830-4836, Vol.32,4830-4836 (2009), 2009.11.
160. Ling PAN, Hisashi SHIMAKOSHI, Takahiro MASUKO, Yoshio HISAEDA, Vitamin B12 Model Complex Catalyzed Methyl Transfer Reaction to Alkylthiol under Electrochemical Conditions with Sacrificial Electrode, Dalton Trans., 44, 9898-9905, Vol.44,9898-9905 (2009), 2009.11.
161. Daisuke Maeda, Hisashi Shimakoshi, Masaaki Abe, Yoshio Hisaeda, Syntheses and photophysical behavior of porphyrin isomer sn(iv) complexes, Inorganic Chemistry, 10.1021/ic901401t, 48, 20, 9853-9860, 2009.11, [URL], 2,3,6,7,12,13,16,17-Octaethylhemlporphycenato Sn(IV) chloride, [Sn IV(OEHPc)CI2], and 2,3,6,7,12,13,16,17- octaethylporphycenato Sn(IV) chloride, [Sn (OEPc)CI2], were synthesized in high yields and fully characterized by various spectroscopic methods. The X-ray crystal structures of the Sn(IV) complexes with porphycene and hemiporphycene were determined for the first time. The photophysical and photochemical properties of the singlet state of the Sn(IV) porphycene and hemiporphycene complexes, structural isomers of porphyrin, have been investigated by fluorescence and phosphorescence spectroscopies. The relatively strong emission and long fluorescence lifetime of the Sn(IV) porphycene complexes indicated by the fluorescence quantum yield and lifetime measurement were observed in the case of the Sn(IV) porphycene ([SnIV(OEPc) CI2], φF = 0.125, τS = 2681 ps; [SnIV(OEP)CI2], φF=0.010, τs=438 ps; [SnIV(OEHPc)CI2], φF=0.027, τS=733 ps). The triplet state of the Sn(IV) complexes was investigated by transient absorption spectroscopy. It became clear that the triplet lifetime of the Sn(IV) porphycene (τT = 49.9μs) was longer when compared to those of the Sn(IV) porphyrin (τT = 32.6 μs) and hemiporphycene complexes (τT = 28.3 μs). These porphyrin isomer Sn(IV) complexes showed the high singlet oxygen generating ability, and the photo-oxidation of the 1,5-hydroxynaphthalene mediated by the Sn(IV) porphycene was the most effective among the complexes. This result Is due to its more effective light absorption In the visible region and indicated that the porphycene is an excellent candidate as a photosensitizer..
162. Ling Pan, Hisashi Shimakoshi, Takahiro Masuko, Yoshio Hisaeda, Vitamin B12 model complex catalyzed methyl transfer reaction to alkylthiol under electrochemical conditions with sacrificial electrode, Dalton Transactions, 10.1039/b909163g, 44, 9898-9905, 2009.11, [URL], Catalytic methyl transfer reactions from methyl tosylate to 1-octanethiol catalyzed by heptamethyl cobyrinate perchlorate, [Cob(II)7C1ester] ClO4, were investigated under electrochemical conditions. As a model study for the cobalamin-dependent methyl transfer reaction from methyltetrahydrofolate to homocysteine, controlled-potential electrolyses were carried out at -1.0 V vs. Ag/AgCl using a zinc plate as the sacrificial anode at 50 °C in the dark. A turnover behaviour for the methyl transfer reaction was observed for the first time under non-enzymatic reaction conditions. Co(I) species, which is generated from the continuous electrolysis of [Cob(II)7C 1ester]ClO4, and its methylated CH3-Co complex were found to be important intermediates. The mechanism for such a methyl transfer reaction was investigated by product analysis, electronic spectroscopy and ESR spin-trapping experiments. A simple vitamin B12 model complex was also utilized as the catalyst for the methyl transfer reaction..
163. H. Shimakoshi, T. Baba, Y. Izeki, A. Endo, C. Adachi, M. Watanabe, Y. Hisaeda, Photosensitizing Properties of the Porphycene Immobilized in Sol-Gel Derived Silica Coating Films
, Tetrahedron Lett., Vol. 49, No.49, 6198-6201 (2008), 2009.10.
164. Hisashi SHIMAKOSHI, Makoto ABIRU, Shinichiro IZUMI, Yoshio HISAEDA, Green molecular transformation by B12-TiO2 hybrid catalyst as an alternative to tributyltin hydride, Chem. Commun, 42, 6427-6429, Vol. 42,6427-6429 (2009), 2009.10.
165. Hisashi Shimakoshi, Makoto Abiru, Shin Ichiro Izumi, Yoshio Hisaeda, Green molecular transformation by a B12-TiO2 hybrid catalyst as an alternative to tributyltin hydride, Chemical Communications, 10.1039/b913255d, 42, 6427-6429, 2009.10, [URL], The B12-TiO2 hybrid catalyst was effectively used for the radical reactions, such as 1,2-migrations of phenyl groups and acyl groups under irradiation by UV light, and the selectivity of the reaction was controlled by the solvent system..
166. Takashi Matsuo, Akihiro Hayashi, Masato Abe, Takaaki Matsuda, Yoshio Hisaeda, Takashi Hayashi, Meso-unsubstituted iron corrole in hemoproteins
Remarkable differences in effects on peroxidase activities between myoglobin and horseradish peroxidase, Journal of the American Chemical Society, 10.1021/ja907428e, 131, 42, 15124-15125, 2009.10, [URL], (Figure Presented) Myoglobin (Mb) and horseradish peroxidase (HRP) were both reconstituted with a meso-unsubstituted iron corrole and their electronic configurations and peroxidase activities were investigated. The appearance of the 540 nm band upon incorporation of the iron corrole into apoMb indicates axial coordination by the proximal histidine imidazole in the Mb heme pocket. Based on 1H NMR measurements using the Evans method, the total magnetic susceptibility of the iron corrole reconstituted Mb was evaluated to be S = 3/2. In contrast, although a band does not appear in the vicinity of 540 nm during reconstitution of the iron corrole into the matrix of HRP, a spectrum similar to that of the iron corrole reconstituted Mb is observed upon the addition of dithionite. This observation suggests that the oxidation state of the corrole iron in the reconstituted HRP can be assigned as +4. The catalytic activities of both proteins toward guaiacol oxidation are quite different; the iron corrole reconstituted HRP decelerates H2O2-dependent oxidation of guaiacol, while the same reaction catalyzed by iron corrole reconstituted Mb has the opposite effect and accelerates the reaction. This finding can be attributed to the difference in the oxidation states of the corrole iron when these proteins are in the resting state..
167. Daisuke MAEDA, Hisashi SHIMAKOSHI, Masaaki ABE, Yoshio HISAEDA, Syntheses and Photophysical Behavior of Porphyrin Isomer Sn(IV) Complexes, Inorg. Chem, 48, 20, 9853-9860, Vol. 48, No.20,9853-9860 (2009), 2009.09.
168. Mamoru FUJITSUKA, Hisashi SHIMAKOSHI, Sachiko TOJO, Lingli CHENG, Daisuke MAEDA, Yoshio HISAEDA, Tetsuro MAJIMA, Electron Transfer in Supramolecular Donor-Acceptor Dyad of Zinc Porphycene, J. Phys. Chem. A, 113, 14, 3330-3335, Vol. 113, No.14, 3330-3335 (2009), 2009.07.
169. Hisashi Shimakoshi, Emiko Sakumori, Kenji Kaneko, Yoshio Hisaeda, B 12-TiO 2 hybrid catalyst for dehalogenation of organic halides, Chemistry Letters, 10.1246/cl.2009.468, 38, 5, 468-469, 2009.07, [URL], A cobalamin derivative, cobyrinie acid, was effectively immobilized on TiO 2, and the hybrid TiO 2 was characterized by UV-vis, XPS, MALDI-TOFMS as well as TEM analysis. The hybrid TiO 2 exhibits high reactivity for dehalogenation of various organic halides such as phenethyl bromide, benzyl bromide, and 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) under irradiation with UV light at room temperature..
170. Ling Pan, Hisashi Shimakoshi, Yoshio Hisaeda, Electrochemical methyl-transfer reaction to alkylthiol catalyzed by hydrophobic vitamin B 12, Chemistry Letters, 10.1246/cl.2009.26, 38, 1, 26-27, 2009.07, [URL], The catalytic methyl-transfer reaction from methyl tosylate to 1-octanethiol was carried out in the presence of heptamethyl cobyrinate perchlorate, hydrophobic vitamin B 12, under electrochemical conditions at -1.0 V vs. Ag/AgCl using a carbon-felt cathode and a zinc plate anode as the sacrificial electrode in an undivided cell. This catalytic reaction proceeded via the formation and dissociation of the cobalt-carbon bond in the hydrophobic vitamin B 12..
171. H. Shimakoshi, E. Sakumori, Kenji Kaneko, Y. Hisaeda, B12-TiO2 Hybrid Catalyst for Dehalogenation of Organic Halides, Chem. Lett., Vol. 38, No.5, 468-469 (2009), 2009.05.
172. Y. Tomiyasu, M. Abe, Y. Morihara, H. Ohgi, T. Otake, Y. Hisaeda, Organic Films Containing Trinuclear Ruthenium Clusters that Exhibit Redox State-dependent Heat-shielding Characteristics, Chem. Lett., Vol. 38, No.5, 492-493 (2009), 2009.05.
173. Mamoru Fujitsuka, Hisashi Shimakoshi, Sachiko Tojo, Lingli Cheng, Daisuke Maeda, Yoshio Hisaeda, Tetsuro Majima, Electron transfer in the supramolecular donor-acceptor dyad of zinc porphycene, Journal of Physical Chemistry A, 10.1021/jp810617a, 113, 14, 3330-3335, 2009.04, [URL], The electron transfer processes of Zn octaethylporphycene (ZnPcn), a structural isomer of Zn octaethylporphyrin, have been investigated mainly using transient absorption spectroscopy. To form a supramolecular donor-acceptor dyad, imide compounds bearing a pyridine group at the N position of the imides have been used as an acceptor. The N atom of the pyridine ring can coordinate to the central Zn ion of ZnPcn. Formation of a supramolecular donor-acceptor dyad, that is, pentacoordinated ZnPcn, was confirmed by steady-state absorption spectroscopy using toluene as a solvent. Charge separation upon excitation of ZnPcn was indicated by efficient fluorescence quenching, especially when pyromellitic diimide was used as the acceptor. Electron transfer processes were confirmed by subpicosecond transient absorption spectroscopy, in which generation of a radical anion of the acceptor and a radical cation of ZnPcn, which was identified by means of γ-ray radiolysis, was confirmed. It became clear that the charge separation rate was smaller than that of the corresponding supramolecular dyads of Zn tetraphenylporphyrin and Zn octaethylporphyrin despite a similar driving force. This observation indicates a larger internal reorganization energy and a smaller coupling element of the ZnPcn dyad..
174. Hisashi Shimakoshi, Kaori Shibata, Yoshio Hisaeda, Molecular recognition of redox-switchable bis-crown moieties assembled on a dicobalt complex (Inorganic Chemistry (2009) 48
7 (1048)), Inorganic Chemistry, 10.1021/ic9003438, 48, 7, 2009.04, [URL].
175. H. Shimakoshi, K. Shibata, Y. Hisaeda, Molecular Recognition of Redox-Switchable Bis-crowns Moieties Assembled on Dicobalt Complex, Inorg. Chem., 48, No.3, 1045-1052 (2009), 2009.03.
176. K. Nakamura, Y. Hisaeda, L. Pan, H. Yamauchi, Methyl Transfer from a Hydrophobic Vitamin B12 Derivative to ArsenicTrioxide, J. Organometal. Chem., No.694, 916 - 921 (2009), 2009.03.
177. Koichiro Nakamura, Yoshio Hisaeda, Ling Pan, Hiroshi Yamauchi, Methyl transfer from a hydrophobic vitamin B12 derivative to arsenic trioxide, Journal of Organometallic Chemistry, 10.1016/j.jorganchem.2008.12.002, 694, 6, 916-921, 2009.03, [URL], The methylation reaction of arsenic trioxide conducted at 37 °C and pH 7.0 for 24 h using hydrophobic methylated vitamin B12, (methyl) (aquo) heptamethylcobyrinate perchlorate, CH3B12 ester, as a methyl donor in the presence of reduced glutathione (GSH) yielded monomethylarsonous acid (MMA), dimethylarsinic acid (DMA), and trimethylarsine oxide (TMAO) as products with a methylation rate over 95%. In contrast, when methylcobalamin (CH3B12) was used as the methyl donor, only MMA and DMA were produced and the methylation rate dropped to around 20%. Reductive demethylation of a methyl-corrinoid coordination complex mediated by GSH is suggested as a mechanism of methyl transfer to arsenic trioxide. The differences observed for different corrinoid coordination complexes with respect to the reactivity of methyl transfer to arsenic is ascribable to differences inherent in the base-on (CH3B12) and base-off (CH3B12 ester) natures of the compounds..
178. Hisashi Shimakoshi, Kaori Shibata, Yoshio Hisaeda, Molecular recognition of redox-switchable bis-crown moieties assembled on a dicobalt complex, Inorganic Chemistry, 10.1021/ic801708v, 48, 3, 1045-1052, 2009.02, [URL], A new dinuclear complex of cobalt(III) having double bis-crown moieties (1) was synthesized in a one-pot multistep reaction between the dinucleating ligand (H2L1), Co(OAc)2 · 4H2O, and 4′-aminomethylbenzo-15-crown 5-ether under aerobic conditions. The complex was characterized by UV-vis, IR, NMR, and CSI-mass spectroscopies, and the axial coordination of the 4′-aminomethylbenzo-15-crown 5-ether on both cobalt centers was confirmed. The bis-crown moieties of 1 acted as a potassium ion binding site with a large association constant (K) of 1.97 × 10 5 M-1 (1:1) caused by the preorganized bis-crown structure. Solvent extraction of K+ (potassium picrate) with 1 was investigated by UV-vis and NMR, and the extracted K+ was quantified by an atomic absorption/flame emission spectrophotometer. The cyclic voltammogram of 1 showed irreversible redox waves at -0.57 V and +0.16 V versus Ag/AgCl in DMF, which are ascribed to the Co(III) and Co(II) redox couple. The large peak separation (A0.73 V) of this redox couple indicates the association and dissociation of the axial amine on the cobalt centers. The irreversible reduction peak of 1 at -0.57 V was shifted in the positive direction by 80 mV in the presence of the potassium ion, showing the complexation of 1 with the potassium ion. The reversible formation and decomposition of the double bis-crown moieties in 1 caused by the electrical stimulus were also investigated by thin-layer UV-vis spectroelectrochemistry. The switching of the double bis-crown structure of 1 was established over four trials with response to electrical energy..
179. K. Aoki, T. Goshima, Y. Kozuka, Y. Kawamori, N. Ono, Y. Hisaeda, H. D. Takagi, M. Inamo, Electron Transfer Reaction of Porphyrin and Porphycene Complexes of Cu(II) and Zn(II) in Acetonitrile, Dalton Trans., No.1, 119-125 (2009), 2009.01.
180. D. Maeda, H. Shimakoshi, M. Abe, Y. Hisaeda, Synthesis and Photochemical Property of a New Molybdenum Porphycene Complex, Dalton Trans., No.1, 140-145 (2009), 2009.01.
181. L. Pan, H. Shimakoshi, Y. Hisaeda, Electrochemical Methyl-transfer Reaction to Alkylthiol Catalyzed by Hydrophobic Vitamin B12, Chem. Lett., No.1, 26-27 (2009), 2009.01.
182. Kaori Aoki, Toshimitsu Goshima, Yohei Kozuka, Yukiko Kawamori, Noboru Ono, Yoshio Hisaeda, Hideo D. Takagi, Masahiko Inamo, Electron transfer reaction of porphyrin and porphycene complexes of Cu(II) and Zn(II) in acetonitrile, Dalton Transactions, 10.1039/b812575a, 1, 119-125, 2009.01, [URL], The outer-sphere one-electron oxidation reaction of the Cu(ii) and Zn(ii) complexes of nonplanar 2,3,7,8,12,13,17,18-octaethyl-5,10,15,20- tetraphenylporphyrin and planar porphycenes as well as those of 2,3,7,8,12,13,17,18-octaethylporphyrin and 5,10,15,20-tetraphenylporphyrin by Cu2+ giving corresponding π-cation radicals was investigated spectrophotometrically in acetonitrile. The electron self-exchange rate constants between the parent porphyrin and porphycene complexes and their π-cation radicals were determined using the Marcus cross relation for the electron transfer reaction. The obtained rate constants are in the order of 109 to 1011 M-1 s-1 for the planar porphyrin and porphycene complexes and 104 to 106 M -1 s-1 for the nonplanar OETPP complexes at T = 25.0 °C. The relatively slow self-exchange reaction of the distorted porphyrin complexes, as compared with those for the planar porphyrin and porphycene complexes, was ascribed to the significant deformation of the complex associated with the oxidation reaction from the parent complex to the corresponding π-cation radical..
183. Daisuke Maeda, Hisashi Shimakoshi, Masaaki Abe, Yoshio Hisaeda, Synthesis and photochemical properties of a new molybdenum porphycene complex, Dalton Transactions, 10.1039/b809262a, 1, 140-145, 2009.01, [URL], A new molybdenum porphycene complex, which is a new complex having oxo and chloro groups at the axial positions, was successfully synthesized. This chloro(oxo)molybdenum(v) complex, [MoV(OEPc)(O)Cl] (1) has strong absorption bands in the visible region attributed to the properties of the porphycene and is very attractive from a photochemical viewpoint. This complex was readily reduced from Mo(v) to Mo(iv) species to yield [Mo IV(OEPc)(O)] under anaerobic irradiation by visible light. This photochemical reaction mechanism is derived from the homolytic cleavage of the axial ligand. Furthermore, this photochemical reduction proceeded very effectively compared to that for the corresponding porphyrin complex..
184. Yuki Tomiyasu, Masaaki Abe, Yasushi Morihara, Hiroyuki Ohgi, Tomiaki Otake, Yoshio Hisaeda, Organic films containing trinuclear ruthenium clusters that exhibit redox-state-dependent heat-shielding characteristics, Chemistry Letters, 10.1246/cl.2009.492, 38, 5, 492-493, 2009, [URL], We report here an unprecedented utility of redox-active transition-metal complexes as heat-shielding materials. A poly-(vinyl alcohol) film containing mixed-valent cluster [Ru 3-(μ 3-O)(μ-CH 3CO 2) 6(mbpy +) 3](PF 6) 3 (1) (mbpy + = 1-methyl-4,4′- bipyridinium cation), which strongly absorbs light in the near-infrared region, shows heat-shielding characteristics whose efficiency is found to highly depend on the redox state of the cluster dye..
185. H. Koshima, T. Tsubouchi, T. Ichihashi, Y. Hisaeda, Antishudder Performance of Low-Molecular-Weight Alkenylsuccinimides , Tribology Online, Vol. 3, No.6, 328-332 (2008), 2008.12.
186. Kazuyuki Ito, Takashi Matsuo, Isao Aritome, Yoshio Hisaeda, Takashi Hayashi, Isolable iron(II)-porphycene derivative stabilized by introduction of trifluoromethyl groups on the ligand framework, Bulletin of the Chemical Society of Japan, 10.1246/bcsj.81.76, 81, 1, 76-83, 2008.12, [URL], Two iron porphycene complexes having four trifluoromethyl groups, chloro-2,7,12,17-tetraethyl-3,6,13,16-tetrakis- (trifluoromethyl) porphycenatoiron(III) [FeIIIClEtio(CF3)4Pc] and its μ-oxo dimer [{FeIIIEtio(CF3)4Pc}2(/U,-Oj], were characterized. The μ,-oxo dimer was easily converted into the monomelic iron(II) complex via the Fe-O bond cleavage in pyridine. This is the first study to obtain a stable iron(ll) species in a series of porphycene iron complexes. The iron(II) species crystallized in the monoclinic system C2/m, and the Fe-Npyridyl (2.007 A) and Fe-Nppyrrolyl (1.958 A) bonds were remarkably short distances among the bispyridine-coordinated iron(II) porphyrins and porphyrinoids. To evaluate the influences of the CF3 substituents and framework structure on the autoreduction, we compared the reactivity of [{FeIIIEtio(CF)4Pc}2(μ-0)] in pyridine with the reference iron porphycene and porphyrins. Autoreduction of [{FemEtio(CF3)4Pc)2(μ-0)] smoothly proceeded at 20°C in pyridine, whereas the reaction of the μ-oxo-bis{2,7,12,17- tetraethyl-3,6,13,16-tetramethylporphycenatoiron(III)} [{Fe IIIEtio(CH3)4Pc}2(μ-0)] was converted into the monomeric iron(III) complex, and the iron(II) species was not available. In contrast, the μ-oxo-bis{l,3,5,7-tetrakis(trifluoromethyl)-2,4, 6,8-tetraethylporphyrinatoiron(III)}[{FeIIIEtio(CF3) 4Por}2(μ-0)] as a structural isomer of [{Fe IIIEtio(CF3)4Pc}2(μ-0)] allowed the autoreduction, although the reaction was very slow and took over one month. These results indicate that the introduction of strong electron-withdrawing groups at the pyrrole β-carbons exhibits a unique reactivity of the iron complex..
187. Koichiro Nakamura, Yoshio Hisaeda, Ling Pan, Hiroshi Yamauchi, Detoxification system for inorganic arsenic
Transformation of As 2O3 into TMAO by vitamin B12 derivatives and conversion of TMAO into arsenobetaine, Chemical Communications, 10.1039/b808937j, 41, 5122-5124, 2008.11, [URL], A new two-step synthetic pathway developed for the transformation of arsenic trioxide [iAs(iii); As2O3] into arsenobetaine (AB; Me3As+CH2CO2-) involves treatment of iAs(iii) with native B12 or biomimetic B12 in the presence of glutathione (GSH) to give TMAO with a high selectivity and a high conversion rate; subsequent treatment of TMAO with iodoacetic acid in the presence of GSH gives arsenobetaine..
188. K. Nakamura, Y. Hisaeda, L. Pan, H. Yamauchi, Detoxification system for inorganic arsenic: transformation of arsenic trioxide into trimethylarsine oxide (TMAO) by vitamin B12 derivatives and conversion of TMAO into arsenobetaine, Chem. Commun., No.41, 5122 - 5124 (2008), 2008.10.
189. Hisashi Shimakoshi, Tatsushi Baba, Yusuke Iseki, Ayataka Endo, Chihaya Adachi, Midori Watanabe, Yoshio Hisaeda, Photosensitizing properties of the porphycene immobilized in sol-gel derived silica coating films, Tetrahedron Letters, 10.1016/j.tetlet.2008.08.003, 49, 43, 6198-6201, 2008.10, [URL], Porphycene was covalently immobilized in a sol-gel silica film deposited on a glass plate, and the immobilized porphycene showed a photosensitizing property with recycling for the photo-oxidation of 1,5-dihydroxynaphthalene..
190. T. Okawara, M. Abe, H. Shimakoshi, Y. Hisaeda, Redox Gradations in Ruthenium Porphycene Complexes and the Porphyrin Analogs:
Axial and Macrocyclic Ligand Effects
, Chem. Lett., Vol. 37, No.9, 906-907 (2008)., 2008.09.
191. T. Matsuo, A. Asano, T. Ando, Y. Hisaeda, T. Hayashi, Photocatalytic Hydrogen Generation Using a Protein-Coated Photosensitizer with Anionic Patches and a Monocationic Electron Mediator, Chem. Commun., No.31, 3684-3686 (2008)., 2008.09.
192. Toru Okawara, Masaaki Abe, Hisashi Shimakoshi, Yoshio Hisaeda, Redox gradations in ruthenium porphycene complexes and the porphyrin analogs
Axial and macrocyclic ligand effects, Chemistry Letters, 10.1246/cl.2008.906, 37, 9, 906-907, 2008.09, [URL], This paper reports synthesis and electrochemistry of six-coordinate ruthenium porphyrin isomers including six novel porphycene complexes with substituted pyridines in the axial positions, in which redox potential control of reversible RuII/RuIII processes is successfully achieved over a 0.7-V potential region by varying the axial ligands and tetrapyrrole ligand structure and substituents..
193. Takashi Matsuo, Atsushi Asano, Tsutomu Ando, Yoshio Hisaeda, Takashi Hayashi, Photocatalytic hydrogen generation using a protein-coated photosensitizer with anionic patches and a monocationic electron mediator, Chemical Communications, 10.1039/b803491e, 31, 3684-3686, 2008.08, [URL], A reconstituted myoglobin with a synthetic cofactor having anionic binding sites effectively works as a photocatalyst for hydrogen generation in the presence of monomethylated bipyridinium..
194. Takeki Hamasaki, Taichi Kashiwagi, Toshifumi Imada, Noboru Nakamichi, Shinsuke Aramaki, Kazuko Toh, Shinkatsu Morisawa, Hisashi Shimakoshi, Yoshio Hisaeda, Sanetaka Shirahata, Kinetic analysis of superoxide anion radical-scavenging and hydroxyl radical-scavenging activities of platinum nanoparticles, Langmuir, 10.1021/la704046f, 24, 14, 7354-7364, 2008.07, [URL], There are few reports on the physiological effects of metal nanoparticles (nps), especially with respect to their functions as scavengers for superoxide anion radical (O2.-) and hydroxy 1 radical (·OH). We tried to detect the scavenging activity of Pt nps using a hypoxanthine-xanthine oxidase system for O2.- and using a Fenton and a UV/H2O2 system for ·OH. Electron spin resonance analysis revealed that 2 nm particle size Pt nps have the ability to scavenge O2.- and ·OH. The calculated rate constant for the O2.-scavenging reaction was 5.03 ± 0.03 × 107 M-1 s-1. However, the analysis of the Fenton and UV/H2O2 system in the presence of Pt nps suggested that the ·OH-scavenging reaction cannot be determined in both systems. Among particle sizes tested from 1 to 5 nm, 1 nm Pt nps showed the highest O2.-scavenging ability. Almost no cytotoxicity was observed even after adherent cells (TIG-1, HeLa, HepG2, WI-38, and MRC-5) were exposed to Pt nps at concentrations as high as 50 mg/L. Pt nps scavenged intrinsically generated reactive oxygen species (ROS) in HeLa cells. Additionally, Pt nps significantly reduced the levels of intracellular O 2.- generated by UVA irradiation and subsequently protected HeLa cells from ROS damage-induced cell death. These findings suggest that Pt nps may be a new type of antioxidant capable of circumventing the paradoxical effects of conventional antioxidants..
195. Hisashi Shimakoshi, Tatsushi Baba, Yusuke Iseki, Isao Aritome, Ayataka Endo, Chihaya Adachi, Yoshio Hisaeda, Photophysical and photosensitizing properties of brominated porphycenes, Chemical Communications, 10.1039/b802730g, 25, 2882-2884, 2008.06, [URL], A heavy atom, bromine, was directly substituted into the porphycene macrocycle to promote intersystem crossing by way of spin-orbit coupling. The singlet oxygen production ability of the porphycene is dramatically enhanced, and the highest value of 0.95 for the quantum yield of singlet oxygen generation (ΦΔ) was obtained for the dibrominated porphycene by visible light excitation..
196. T. Hamasaki, T. Kashiwagi, T. Imada, N. Nakamichi, S. Arakami, K. Toh, S. Morisawa, H. Shimakoshi, Y. Hisaeda, S. Shirahata, Kinetic Analysis of Superoxide Anion Radical-Scavenging and Hydroxyl Radical-Scavenging Activities of Platinum Nanoparticles, Langmuir, Vol. 24, No.14, 7354-7364 (2008)., 2008.04.
197. T. Baba, H. Shimakoshi, A. Endo, C. Adachi, Y. Hisaeda, Photophysical and Photocatalytic Properties of β-Sulfonatoporphycenes, Chem. Lett., Vol.37, No.3, 264-265, 2008.03.
198. H. Shimakoshi, T. Baba, Y. Iseki, I. Aritome, A. Endo, C. Adachi, Y. Hisaeda, Photophysical and Photosensitizing Properties of Brominated Porphycenes, Chem. Commun., No.25, 2882-2884 , 2008.03.
199. H. Koshima, T. Tsubouchi, Y. Hisaeda, Study of Factors Influencing Factors of Phenyl Salicylates to the High-Temperature Detergency, Tribology Online, Vol.3, No.3, 195-199 (2008)., 2008.03.
200. Tatsushi Baba, Hisashi Shimakoshi, Ayataka Endo, Chihaya Adachi, Yoshio Hisaeda, Photophysical and photocatalytic properties of β-sulfonatoporphycenes, Chemistry Letters, 10.1246/cl.2008.264, 37, 3, 264-265, 2008.03, [URL], The photophysical properties and photooxidation ability of the β-sulfonatoporphycenes are reported. The photophysical parameters depend on the number of substitutions. The disulfonated porphycene 2 is expected to be a new photosensitizer due to its high catalytic activity and photostability..
201. Takashi Matsuo, Kazuyuki Ito, Yuji Nakashima, Yoshio Hisaeda, Takashi Hayashi, Effect of peripheral trifluoromethyl groups in artificial iron porphycene cofactor on ligand binding properties of myoglobin, Journal of Inorganic Biochemistry, 10.1016/j.jinorgbio.2007.07.032, 102, 2, 166-173, 2008.02, [URL], An iron porphycene, a structural isomer of iron porphyrin, with trifluromethyl groups at the peripheral position of the framework was incorporated into sperm whale apomyoglobin. The prepared myoglobin shows the higher O2 affinity than the native protein. However, the oxygen affinity of the reconstituted myoglobin is lower than that of the myoglobin having an iron porphycene without trifluromethyl groups, which is mainly originated from the enhancement of the O2 dissociation. The CO affinity of the myoglobin with the trifluoromethylated iron porphycene is similar to that observed for the reference protein having the iron porphycene without trifluoromethyl groups, although their C-O stretching frequencies are significantly different. The relationship between the electronic states of the porphycene ring and the ligand bindings is discussed..
202. K. Ito, T. Matsuo, I. Aritome, Y. Hisaeda, T. Hayashi, solable Iron(II)-Porphycene Derivative Stabilized by Introduction of Trifluoromethyl Groups on the Ligand Framework, Bull. Chem. Soc. Jpn., Vol.81, No.1, 76-83 (2008). (BCSJ Award Article), 2008.01.
203. T. Matsuo, K. Ito, Y. Nakashima, Y. Hisaeda, T. Hayashi, Effect of Peripheral Trifluoromethyl Groups in Artificial Iron Porphycene Cofactor on Ligand Binding Properties of Myoglobin, J. Inorg. Biochem., Vol.102, 166-173, 2007.11.
204. Katsuyoshi HARADA, Masatomo MAKINO, Hiroshi SUGIMOTO, Shun HIROTA, Takashi MATSUO, Yoshitsugu SHIRO, Yoshio HISAEDA, Takashi HAYASHI, Structure and Ligand Binding Properties of Myoglobins Reconstituted with Monodepropionated Heme: Functional Role of Each Heme-Propionate Side Chain, Biochemistry, 2007.10.
205. Takashi Matsuo, Dai Murata, Yoshio Hisaeda, Hiroshi Hori, Takashi Hayashi, Porphyrinoid chemistry in hemoprotein matrix
Detection and reactivities of iron(IV)-oxo species of porphycene incorporated into horseradish peroxidase, Journal of the American Chemical Society, 10.1021/ja074685f, 129, 43, 12906-12907, 2007.10, [URL], The iron porphycene with two propionates at the peripheral positions of the framework was incorporated into the heme pocket of horseradish peroxidase. In the presence of hydrogen peroxide, the ferric iron porphycene was smoothly converted into the iron(IV)-oxo porphycene π-cation radical species, which was confirmed by the appearance of a band around 800 nm in the UV-vis spectrum. The protein with the iron porphycene showed a 10-fold higher reactivity for the thioanisole oxidation when compared to the native protein. In contrast, the guaiacol oxidation proceeded with similar reaction rates in both proteins. The kinetic analyses indicated that the ferric porphycene in the protein more slowly reacts with hydrogen peroxide than the native heme, whereas the high oxidation states show higher reactivities during oxidations of an organic substrate. The formation of the iron(IV)-oxo species of porphycene and its reactivities in the hemoprotein matrix are demonstrated..
206. Katsuyoshi Harada, Masatomo Makino, Hiroshi Sugimoto, Shun Hirota, Takashi Matsuo, Yoshitsugu Shiro, Yoshio Hisaeda, Takashi Hayashi, Structure and ligand binding properties of myoglobins reconstituted with monodepropionated heme
Functional role of each heme propionate side chain, Biochemistry, 10.1021/bi7007068, 46, 33, 9406-9416, 2007.08, [URL], Two heme propionate side chains, which are attached at the 6 and 7 positions of the heme framework, are linked with Arg45 and Ser92, respectively, in sperm whale myoglobin. To evaluate the role of each propionate, two kinds of one-legged hemins, 6-depropionated and 7-depropionated protohemins, were prepared and inserted into the apomyoglobin to yield two reconstituted proteins. Structural data of the reconstituted myoglobins were obtained via an X-ray crystallographic analysis at a resolution of 1.1-1.4 Å and resonance Raman spectroscopy. It was found that the lack of the 6-propionate reduces the number of hydrogen bonds in the distal site and clearly changes the position of the Arg45 residue with the disrupting Arg45-Asp60 interaction. In contrast, the removal of the 7-propionate does not cause a significant structural change in the residues of the distal and proximal sites. However, the resonance Raman studies suggested that the coordination bond strength of the His93-Fe bond for the protein with the 7-depropionated protoheme slightly increases compared to that for the protein with the native heme. The O2 and CO ligand binding studies for the reconstituted proteins with the one-legged hemes provide an important insight into the functional role of each propionate. The lack of the 6-propionate accelerates the O2 dissociation by ca. 3-fold compared to those of the other reconstituted and native proteins. The lack of the 7-propionate enhances the CO affinity by 2-fold compared to that of the protein with the native heme. These results indicate that the 6-propionate clearly contributes to the stabilization of the bound O2, whereas the 7-propionate plays an important role in the regulation of the Fe-His bond..
207. Keishiro Tahara, Hisashi Shimakoshi, Akihiro Tanaka, Yoshio Hisaeda, Synthesis and characterization of vitamin B12-hyperbranched polymer, Tetrahedron Letters, 10.1016/j.tetlet.2007.05.092, 48, 29, 5065-5068, 2007.07, [URL], Vitamin B12-hyperbranched polymer was synthesized and characterized by UV-vis and NMR spectroscopy as well as DLS. The shape of hybrid polymer was also directly observed by TEM. Microenvironmental polarity around vitamin B12 derivative on the polymer was evaluated by UV-vis absorption peak with α-band of vitamin B12 chromophore..
208. Takashi MATSUO, Dai MURATA, Yoshio HISAEDA, Hiroshi HORI, Takashi HAYASHI, Porphyrinoid Chemistry in Hemoprotein Matrix: Detection and Reactivities of Iron(IV)-Oxo Species of Porphycene Incorporated into Horseradish Peroxidase, J. Am. Chem. Soc., Vol.129, No.43, pp.12906-12907, 2007.06.
209. Keishiro TAHARA, Hisashi SHIMAKOSHI, Akihiro TANAKA, Yoshio HISAEDA, Synthesis and characterization of vitamin B12-hyperbranched polymer, Tetrahedron Lett., Vol.48, No.29, pp.5065-5068, 2007.05.
210. Md Abdul Jabbar, Hisashi Shimakoshi, Yoshio Hisaeda, Enhanced reactivity of hydrophobic vitamin B12 towards the dechlorination of DDT in ionic liquid, Chemical Communications, 10.1039/b700725f, 16, 1653-1655, 2007.05, [URL], The electrolytic reductive dechlorination of 1,1-bis(p-chlorophenyl)-2,2,2- trichloroethane (DDT) in the ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) in the presence of a cobalamin derivative afforded 1,1′-(ethylidene)bis(4-chlorobenzene) (DDO) and 1,1′-(ethenylidene)bis(4-chlorobenzene) (DDNU) with 1,1′-(2- chloroethylidene)bis(4-chlorobenzene) (DDMS); the enhanced reactivity, as well as the recyclability of the cobalamin derivative catalyst in IL, makes the present system more efficient for the development of "green" technologies..
211. Md. Abdul JABBAR, Hisashi SHIMAKOSHI, Yoshio HISAEDA, Enhanced Reactivity of Hydrophobic Vitamin B12 towards the Dechlorination of DDT in Ionic Liquid, Chem. Commun., pp.1653-1655, 2007.04.
212. Takashi Hayashi, Dai Murata, Masatomo Makino, Hiroshi Sugimoto, Takashi Matsuo, Hideaki Sato, Yoshitsugu Shiro, Yoshio Hisaeda, Crystal structure and peroxidase activity of myoglobin reconstituted with iron porphycene, Inorganic Chemistry, 10.1021/ic061130x, 45, 26, 10530-10536, 2006.12, [URL], The incorporation of an artificially created metal complex into an apomyoglobin is one of the attractive methods in a series of hemoprotein modifications. Single crystals of sperm whale myoglobin reconstituted with 13,16-dicarboxyethyl-2,7-diethyl-3,6,12,17-tetramethylporphycenatoiron(III) were obtained in the imidazole buffer, and the 3D structure with a 2.25-Å resolution indicates that the iron porphycene, a structural isomer of hemin, is located in the normal position of the heme pocket. Furthermore, it was found that the reconstituted myoglobin catalyzed the H2O 2-dependent oxidations of substrates such as guaiacol, thioanisole, and styrene. At pH 7.0 and 20°C, the initial rate of the guaiacol oxidation is 11-fold faster than that observed for the native myoglobin. Moreover, the stopped-flow analysis of the reaction of the reconstituted protein with H 2O2 suggested the formation of two reaction intermediates, compounds II- and III-like species, in the absence of a substrate. It is a rare example that compound III is formed via compound II in myoglobin chemistry. The enhancement of the peroxidase activity and the formation of the stable compound III in myoglobin with iron porphycene mainly arise from the strong coordination of the Fe-His93 bond..
213. Md. Abdul JABBAR, Isao ARITOME, Hisashi SHIMAKOSHI and Yoshio HISAEDA, 1,1'-(Ethenylidene)bis(4-chlorobenzene), Acta Cryst.C, 62, Part 11, o663-o665, 2006.11.
214. Takashi HAYASHI, Dai MURATA, Masatomo Makino, Hiroshi Sugimoto, Takashi MATSUO, Hideaki SATO, Yoshitsugu Shiro and Yoshio HISAEDA, Crystal Structure and Peroxidase Activity of Myoglobin Reconstituted with Iron Porphycene, Inorg. Chem., 45, No.26, 10530-10536, 2006.11.
215. Md Abdul Jabbar, Isao Aritome, Hisashi Shimakoshi, Yoshio Hisaeda, 1,1′-(Ethenylidene)bis(4-chlorobenzene), Acta Crystallographica Section C: Crystal Structure Communications, 10.1107/S0108270106040753, 62, 11, 2006.11, [URL], The title compound, C14H10Cl2, crystallizes as colourless prisms with two symmetry-independent molecules in the unit cell. Numerous intermolecular C-H⋯π interactions dominate in the crystal structure, where C-H⋯Cl and long Cl⋯Cl contacts are also observed..
216. Hiromitsu Uehara, Masaaki Abe, Yoshio Hisaeda, Kohei Uosaki, Yoichi Sasaki, Immobilization of a Binuclear Ruthenium(III) Complex on a Gold (111) Surface: Observations of Proton-coupled Electron Transfer and Electrochemical Durability in Aqueous Media, Chem. Lett., 35, No.10, 1178-1179, 2006.10.
217. Yoshio HISAEDA, Takahiro MASUKO, Erika Hanashima and Takashi HAYASHI, Organic/Inorganic Hybrid Nanomaterials with Vitamin B12 Functions, Sci. Tech. Adv. Mater., 7, No.7, 655-661, 2006.10.
218. Hiromitsu UEHARA, Masaaki ABE, Yoshio HISAEDA, Kohei UOSAKI and Yoichi SASAKI, Immobilization of a Binuclear Ruthenium(III) Complex on a Gold (111) Surface: Observations of Proton-coupled Electron Transfer and Electrochemical Durability in Aqueous Media, Chem. Lett., Vol.35, No.10, pp.1178-1179, 2006.10.
219. Hiromitsu Uehara, Masaaki Abe, Yoshio Hisaeda, Kohei Uosaki, Yoichi Sasaki, Immobilization of a binuclear ruthenium(III) complex on a gold (111) surface
Observations of proton-coupled electron transfer and electrochemical durability in aqueous media, Chemistry Letters, 10.1246/cl.2006.1178, 35, 10, 1178-1179, 2006.10, [URL], An oxo-bridged diruthenium(III) complex was immobilized on a Au(111) electrode through the coordination by terminal pyridyl groups of self-assembled monolayer of alkyl chains, and the immobilized complex underwent proton-coupled electron-transfer reactions in a very wide pH range (2-12) with remarkable monolayer durability for multiple potential cycles..
220. Yoshio Hisaeda, Takahiro Masuko, Erika Hanashima, Takashi Hayashi, Organic/inorganic hybrid nanomaterials with vitamin B12 functions, Science and Technology of Advanced Materials, 10.1016/j.stam.2006.08.003, 7, 7, 655-661, 2006.10, [URL], A hybrid nanomaterial was prepared by human serum albumin (HSA) and vitamin B12 derivatives. The incorporation of hydrophobic vitamin B12 derivatives, which have ester groups in place of the peripheral amide moieties of the natural cobalamin, into HSA is primarily controlled by the hydrophobicity of the peripheral ester groups. Microenvironmental property around the hydrophobic vitamin B12 in HSA was examined by fluorescence and fluorescence polarization measurements. The hydrophobic vitamin B12 itself in HSA is in a microenvironment equivalent in medium polarity to dichloromethane. The molecular motion of hydrophobic vitamin B12 in HSA was markedly suppressed under such microenvironmental conditions. Carbon-skeleton rearrangement reaction of an alkyl radical derived from an alkyl ligand bound to the hydrophobic vitamin B12 was markedly favored in HSA aqueous solution, relative to the reactions in methanol and benzene. The 1,2-migration of the electron-withdrawing group arises from both the suppression of molecular motion and desolvation effects on the alkylated hydrophobic vitamin B12 in HSA..
221. Takashi MATSUO, Hirokazu NAGAI, Yoshio HISAEDA and Takashi HAYASHI, Construction of glycosylated myoglobins by reconstitutional method, Chem. Commun., pp.3131-3133, 2006.08.
222. Takashi MATSUO, Takahiro IKEGAMI, Hideaki SATO, Yoshio HISAEDA and Takashi HAYASHI, Ligand Binding Properties of Two Kinds of Reconstituted Myoglobins with Iron Porphycene Having Propionates: Effect of -Pyrrolic Position of Two Propionate Side Chains in Porphycene Framework, J. Inorg. Biochem., Vol.100, pp.1265-1271, 2006.07.
223. Takashi Matsuo, Hirokazu Nagai, Yoshio Hisaeda, Takashi Hayashi, Construction of glycosylated myoglobin by reconstitutional method, Chemical Communications, 10.1039/b606060a, 29, 3131-3133, 2006.07, [URL], An artificial prosthetic group having β-galactosyl moieties was synthesized and inserted into sperm whale apomyoglobin to successfully afford a glycosylated myoglobin..
224. Takashi Matsuo, Takahiro Ikegami, Hideaki Sato, Yoshio Hisaeda, Takashi Hayashi, Ligand binding properties of two kinds of reconstituted myoglobins with iron porphycene having propionates
Effect of β-pyrrolic position of two propionate side chains in porphycene framework, Journal of Inorganic Biochemistry, 10.1016/j.jinorgbio.2006.02.018, 100, 7, 1265-1271, 2006.07, [URL], An iron porphycene containing two propionate side chains at the 12th and 17th β-pyrrolic positions of the porphycene ring was synthesized and incorporated into sperm whale apomyoglobin in order to investigate the O2 and CO binding properties of the reconstituted ferrous myoglobin. The protein showed a slower O2 dissociation rate by 1/20, compared to the native myoglobin, whereas the CO dissociation rates were found to be almost the same. This tendency is similar to the result of a previous study on the reconstituted myoglobin with a porphycene having the propionates at the 13th and 16th β-pyrrolic positions. However, the present myoglobin showed a faster O2 dissociation than the previously studied myoglobin. This finding suggests that the position of the two propionates as well as the symmetry of the porphycene framework is an important factor for obtaining a stable oxygenated iron porphycene myoglobin..
225. Koji KANO, Hiroaki KITAGISHI, Camille DAGALLIER, Masahito KODERA, , Iron Porphyrin-Cyclodextrin Supramolecular Complex as a Functional Model of Myoglobin in Aqueous Solution, Inorg. Chem., Vol.45, No.11, pp.4448-4460, 2006.06.
226. Daisuke Maeda, Isao Aritome, Hisashi Shimakoshi, Yoshio Hisaeda, Bis[(2,3,6,7,12,13,16,17-octaethylporphycenato)oxomolybdenum(V)] hexamolybdate(VI), Acta Crystallographica Section E: Structure Reports Online, 10.1107/S1600536806016461, 62, 6, 2006.06, [URL], The title compound, [Mo(C36H44N4)O] 2[Mo6O19], contains a five-coordinate molybdenum-porphycene cationic complex, accompanied by a centrosymmetric hexamolybdate counter-anion. This is the first structure for a molybdenum porphycene. The shape of the central N4 cavity is rectangular, enlarged lengthwise by metal coordination, and the mean short and long N⋯N distances defining the N4 cavity are 2.582(9) and 3.031(9), respectively..
227. Daisuke MAEDA, Isao ARITOME, Hisashi SHIMAKOSHI and Yoshio HISAEDA, Oxo(2,3,6,7,12,13,16,17-octaethylporphycenato) molybdenum(V) hexamolybdate, Acta Cryst.E, Vol.E62, pp.m1272-m1274, 2006.05.
228. Koji Kano, Hiroaki Kitagishi, Camille Dagallier, Masahito Kodera, Takashi Matsuo, Takashi Hayashi, Yoshio Hisaeda, Shun Hirota, Iron porphyrin-cyclodextrin supramolecular complex as a functional model of myoglobin in aqueous solution, Inorganic Chemistry, 10.1021/ic060137b, 45, 11, 4448-4460, 2006.05, [URL], The 1:1 inclusion complex of 5,10,15,20-tetrakis(4-sulfonatophenyl) porphinato iron(II) (FeIITPPS) and an O-methylated β-cyclodextrin dimer having a pyridine linker (1) binds dioxygen reversibly in aqueous solution. The O2 adduct was very stable (t1/2 = 30.1 h) at pH 7.0 and 25°C. ESI-MS and NMR spectroscopic measurements and molecular mechanics (MM) calculations indicated the inclusion of the sulfonatophenyl groups at the 5- and 15-positions of FeIIITPPS or FeIITPPS into two cyclodextrin moieties of 1, to form a supramolecular 1:1 complex (hemoCD1 for the FeIITPPS complex), whose iron center is completely covered by two cyclodextrin moieties. Equilibrium measurements and laser flash photolysis provided the affinities (P 1/2O2 and P1/2CO) and rate constants for O2 and CO binding of hemoCD1 (konO2, koffO2, konCO, and k offCO). The CO affinity relative to the O2 affinity of hemoCD1 was abnormally high. Although resonance Raman spectra suggested weak back-bonding of dπ(Fe) → π*(CO) and hence a weak CO-Fe bond, the CO adduct of hemoCD1 was very stable. The hydrophobic CO molecule dissociated from CO-hemoCD1 hardly breaks free from a shallow cleft in hemoCD1 surrounded by an aqueous bulk phase leading to fast rebinding of CO to hemoCD1. Isothermal titration calorimetry furnished the association constant (KO2), ΔH°, and ΔS° for O2 association to be (2.71 ± 0.51) × 104 M-1, -65.2 ± 4.4 kJ mol-1, and -133.9 ± 16.1 J mol-1 K-1, respectively. The autoxidation of oxy-hemoCD1 was accelerated by H+ and OH-. The inorganic anions also accelerated the autoxidation of oxy-hemoCD1. The O 2-FeII bond is equivalent to the O2 •--FeIII bond, which is attacked by the inorganic anions or the water molecule to produce met-hemoCD1 and a superoxide anion..
229. Michihiro SHIRAKAWA, Norifumi FUJITA, Hisashi SHIMAKOSHI, Yoshio HISAEDA and Seiji SHINKAI, Molecular Programming of Organogelators Which Can Accept [60]Fullerene by Encapsulation, Tetrahedron, Vol.62, pp.2016-2024, 2006.03.
230. Michihiro Shirakawa, Norifumi Fujita, Hisashi Shimakoshi, Yoshio Hisaeda, Seiji Shinkai, Molecular programming of organogelators which can accept [60]fullerene by encapsulation, Tetrahedron, 10.1016/j.tet.2005.07.125, 62, 9, 2016-2024, 2006.02, [URL], New porphyrin-based gelators bearing eight hydrogen-bond-forming amide groups at their periphery were synthesized. They acted as versatile gelators for aromatic solvents. SEM and TEM observations and X-ray crystallographic analysis established that they tend to aggregate into a two-dimensional sheet-like structure utilizing the intermolecular hydrogen-bonding interaction. In this structure the porphyrin-porphyrin π-π stacking interaction is not involved because of the energetically-predominant hydrogen-bonding interactions, keeping the space distance of 12.9 Å. Very interestingly, when C60 was added, the morphology was transformed to a one-dimensional fibrous structure, which can enjoy a porphyrin-C60-porphyrin interaction. This multicapsular structure having porphyrin-based compartments for hosting C 60 was further characterized by XRD, EPR of a Cu(II) analogue, and the theoretical calculation. Thus, this paper presents a new concept, 'molecular recognition in gel', which is effective for the weak host-guest interaction..
231. T. Matsuo, H. Nagai, Y. Hisaeda, T. Hayashi, Construction of glycosylated myoglobins by reconstitutional method, Chem. Commun., 3131-3133, 2006.01.
232. T. Matsuo, T. Ikegami, H. Sato, Y. Hisaeda, T. Hayashi, Ligand Binding Properties of Two Kinds of Reconstituted Myoglobins with Iron Porphycene Having Propionates: Effect of β-Pyrrolic Position of Two Propionate Side Chains in Porphycene Framework, J. Inorg. Biochem., 100, 1265-1271, 2006.01.
233. K. Kano, H. Kitagishi, C. Dagallier, M. Kodera, T. Matsuo, T. Hayashi, Y. Hisaeda, S. Hirota, Iron Porphyrin-Cyclodextrin Supramolecular Complex as a Functional Model of Myoglobin in Aqueous Solution, Inorg. Chem., 45, No.11, 4448-4460, 2006.01.
234. D. Maeda, I. Aritome, H. Shimakoshi, Y. Hisaeda, Oxo(2,3,6,7,12,13,16,17-octaethylporphycenato) molybdenum(V) hexamolybdate, Acta Cryst.E, E62, m1272-m1274, 2006.01.
235. M. Shirakawa, N. Fujita, H. Shimakoshi, Y. Hisaeda, S. Shinkai, Molecular Programming of Organogelators Which Can Accept [60]Fullerene by Encapsulation, Tetrahedron, Vol.62, 2016-2024, 2006.01.
236. H. Shimakoshi, I. Aritome, S. Hirota, Y. Hisaeda, Dioxygen Binding to a Cobalt(II) Porphycene Complex and its Auto-oxidized Cobalt(III) Complex, Bull. Chem. Soc. Jpn., 10.1246/bcsj.78.1619, 78, 9, 1619-1623, 78, No.9, 1619-1623, 2005.09.
237. Y. Ohama, Y. Heike, T. Sugahara, K. Sakata, N. Yoshimura, Y. Hisaeda, M. Hosokawa, S. Takashima, K. Kato, Gene transfection into HeLa cells by vesicles containing cationic peptide lipid, Bioscience, Biotechnology and Biochemistry, 10.1271/bbb.69.1453, 69, 8, 1453-1458, 69, No.8, 1453-1458, 2005.08.
238. H. Shimakoshi, S. Kudo, Y. Hisaeda, Recycled Catalysis of a Hydrophobic Vitamin B12 in an Ionic Liquid, Chem. Lett., 10.1246/cl.2005.1096, 34, 8, 1096-1097, No.8, 1096-1097, 2005.08.
239. H. Shimakoshi, S. Hirose, M. Ohba, T. Shiga, H. Okawa, Y. Hisaeda, Synthesis and Redox Behavior of Dicobalt Complexes Having Flexible and Rigid Linkers, Bull. Chem. Soc. Jpn., 10.1246/bcsj.78.1040, 78, 6, 1040-1046, 78, No.6, 1040-1046, 2005.06.
240. H. Shimakoshi, Y. Maeyama, T. Kaieda, T. Matsuo, E. Matsui, Y. Naruta, Y. Hisaeda, Hydrophobic Vitamin B12 Part 20: Supernucleophilicity of Co(I) Heptamethyl Cobyrinate toward Various Organic Halides, Bull. Chem. Soc. Jpn., 10.1246/bcsj.78.859, 78, 5, 859-863, Vol.78, No.5, 859-863, 2005.05.
241. T. Sugawara, S. Kawashima, A. Oda, Y. Hisaeda, K. Kato, Preparation of cationic immunovesicles containing cationic peptide lipid for specific drug delivery to target cells, Cytotechnology, International Journal of Cell Culture and Biotechnology incorporating Methods in Cell Science, 10.1007/s10616-005-3764-5, 47, 1-3, 51-57, Vol.47, No.1-3, 51-57, 2005.01.
242. H. Shimakoshi, H. Takemoto, I. Aritome, Y. Hisaeda, Redox Switchable Molecular Containers Consisting of Dicobalt Complexes, Inorg. Chem., 10.1021/ic051482o, 44, 25, 9134-9136, 44, No.25, 9134-9136, 2005.01.
243. T. Matsuo, T. Tsuruta, K. Maehara, H. Sato, Y. Hisaeda, T. Hayashi, Preparation and O2 Binding Study of Myoglobin Having a Cobalt Porphycene, Inorg. Chem., 10.1021/ic0513639, 44, 25, 9391-9396, 44, No.25, 9391-9396, 2005.01.
244. H. Shimakoshi, I. Aritome, M. Tokunaga, Y. Hisaeda, (Z)-2,3-Dichloro-1,1,4,4-tetrakis(4-chlorophenyl)but-2-ene, Acta Cryst.E, 10.1107/S160053680501768X, 61, O2063-O2064, E61, o2063-o2064, 2005.01.
245. H. Sato, M. Watanabe, Y. Hisaeda, T. Hayashi, Unusual Ligand Discrimination by a Myoglobin Reconstituted with a Hydrophobic Domain-Linked Heme, J. Am. Chem. Soc., 10.1021/ja044984u, 127, 1, 56-57, Vol.127, No.1, 56-57, 2005.01.
246. Yoshio Hisaeda, Hisashi Shimakoshi, Green molecular transformations mediated by vitamin B12 related metal complexes as homogeneous and heterogeneous catalysts, Yuki Gosei Kagaku Kyokaishi/Journal of Synthetic Organic Chemistry, 10.5059/yukigoseikyokaishi.63.780, 63, 8, 780-790, 2005.01, [URL], Vitamin B12-dependent enzymes, involving the cobalt species as a catalytic center, mediate various molecular transformations in vivo. In order to use vitamin B12 derivatives (cobalamins) as green catalysts, various studies have been carried out such as a chemical modification of cobalamin or the fixation of B12 derivative on electrodes. The Co(I) species of vitamin B12 derivative is widely known as a supernucleophile that forms an alkylated complex by reaction with an alkyl halide. Such reaction is efficient for dehalogenation of various organic halides. Therefore, vitamin B12 derivatives can be used as catalysts for reductive degradation of organic pollutant such as DDT. In addition, the alkylated complex is a useful reagent for forming radical species as the cobalt-carbon bond is readily cleaved homolytically by photolysis or electrolysis. Therefore, the application of the alkylated complex to organic synthesis is quite interesting from the viewpoint of a radical-forming reagent. This review article summarizes recent progress in homogeneous and heterogeneous catalytic reactions mediated by vitamin B12 derivatives..
247. T. Matsuo, H. Dejima, S. Hirota, D. Murata, H. Sato, T. Ikegami, H. Hori, Y. Hisaeda, T. Hayashi, Ligand binding Properties of Myoglobin Reconstituted with Iron Porphycene: Unusual O2 Binding selectivity against CO Binding, J. Am. Chem. Soc., 10.1021/ja045680m, 126, 49, 16007-16017, Vol.126, No.49, 16007-16017, 2004.12.
248. Takashi Matsuo, Hjrohisa Dejima, Shun Hirota, Dai Murata, Hideaki Sato, Takahiro Ikegami, Hiroshi Hori, Yoshio Hisaeda, Takashi Hayashi, Ligand binding properties of myoglobin reconstituted with iron porphycene
Unusual O2 binding selectivity against CO binding, Journal of the American Chemical Society, 10.1021/ja045880m, 126, 49, 16007-16017, 2004.12, [URL], Sperm whale myoglobin, an oxygen storage hemoprotein, was successfully reconstituted with the iron porphycene having two propionates, 2,7-diethyl-3,6,12,17-tetramethyl-13,16-bis(carboxyethyl)-porphycenatoiron. The physicochemical properties and ligand bindings of the reconstituted myoglobin were investigated. The ferric reconstituted myoglobin shows the remarkable stability against acid denaturation and only a low-spin characteristic in its EPR spectrum. The Fe(III)/Fe(II) redox potential (-190 mV vs NHE) determined by the spectroelectrochemical measurements was much lower than that of the wild-type. These results can be attributed to the strong coordination of His93 to the porphycene iron, which is induced by the nature of the porphycene ring symmetry. The O2 affinity of the ferrous reconstituted myoglobin is 2600-fold higher than that of the wild-type, mainly due to the decrease in the O2 dissociation rate, whereas the CO affinity is not so significantly enhanced. As a result, the O2 affinity of the reconstituted myoglobin exceeds its CO affinity (M = KCO/KO2 < 1). The ligand binding studies on H64A mutants support the fact that the slow O 2 dissociation of the reconstituted myoglobin is primarily caused by the stabilization of the Fe-O2 σ-bonding. The IR spectra for the carbon monoxide (CO) complex of the reconstituted myoglobin suggest several structural and/or electrostatic conformations of the Fe-C-O bond, but this is not directly correlated with the CO dissociation rate. The high O2 affinity and the unique characteristics of the myoglobin with the iron porphycene indicate that reconstitution with a synthesized heme is a useful method not only to understand the physiological function of myoglobin but also to create a tailor-made function on the protein..
249. T. Hayashi, T. Nakagawa, K. Harada, T. Matsuo, Y. Hitomi, Y. Hisaeda, Chemical Properties of Sperm Whale Myoglobins Reconstituted with Monopropionate Hemins, Chem. Lett., 10.1246/cl.2004.1512, 33, 11, 1512-1513, Vol.33, No.11, 1512-1513, 2004.11.
250. Hisashi Shimakoshi, Mami Tokunaga, Tatsushi Baba, Yoshio Hisaeda, Erratum
Photochemical dechlorination of DDT catalyzed by a hydrophobic vitamin B12 and a photosensitizer under irradiation with visible light (Chemical Communications (2004) (1806-1807) DOI: 10.1039/b406400c), Chemical Communications, 10, 19, 2242, 2004.11.
251. Hisashi Shimakoshi, Isao Aritome, Mami Tokunaga, Yoshio Hisaeda, (E)-2,3-Dichloro-1,1,4,4-tetrakis(4-chlorophenyl)-but-2-ene, Acta Crystallographica Section E: Structure Reports Online, 10.1107/S1600536804018537, 60, 9, 2004.09, [URL], The title compound, C28H18Cl6, was obtained by the electrolysis of 2,2,2-trichloro-1,1-bis(4-chlorophenyl)ethane (DDT) in the presence of a catalytic amount of a cobalamin derivative. The molecule has a centre of symmetry, and the alkene moiety has an E configuration..
252. H. Shimakoshi, I. Aritome, M. Tokunaga, Y. Hisaeda, 1,1,4,4-tetrakis(4-chlorophenyl)-2,3-dichloro-2-butene (E, Z), Acta Cryst.E, Vol. E60, o1470-o1471, 2004.08.
253. H. Shimakoshi, M. Tokunaga, T. Baba, Y. Hisaeda, Photochemical dechlorination of DDT catalyzed by a hydrophobic vitamin B12 and a photosensitizer under irradiation with visible light, Chem. Commun., 10.1039/b406400c, 16, 1806-1807, 1806-1807, 2004.08.
254. H. Sato, T. Hayashi, Y. Hisaeda, High peroxidase activity of sperm whale myoglobin by hybridization of modified-heme reconstitution and distal histidine mutation, J. Porphyrins Phthalocyanines, Vol.8, 823, 2004.07.
255. D. Murata, H. Sato, T. Hayashi, Y. Hisaeda, Enhancement of peroxidase activity in myoglobin by iron porphycene as a prosthetic group, J. Porphyrins Phthalocyanines, Vol.8, 775, 2004.07.
256. T. Matsuo, T. Hayashi, Y. Hisaeda, Ligand binding properties of reconstituted myoglobin with iron porphycene, J. Porphyrins Phthalocyanines, Vol.8, 763, 2004.07.
257. I. Aritome, H. Shimakoshi, T. Hayashi, Y. Hisaeda, Reaction of b-brominated porphycene cobalt(III) with olefins, J. Porphyrins Phthalocyanines, Vol.8, 596, 2004.07.
258. T. Hayashi, H. Sato, T. Matsuo, Y. Hisaeda, Modification of hemoproteins by reconstitutional methods, J. Porphyrins Phthalocyanines, Vol.8, 395, 2004.07.
259. T. Hayashi, H. Sato, T. Matsuo, T. Matsuda, Y. Hitomi, Y. Hisaeda, Enhancement of enzymatic activity for myoglobins by modification of heme-propionate side chains, J. Porphyrins Phthalocyanines, 8, 1-3, 255-264, Vol.8, 255-264, 2004.07.
260. T. Baba, H. Shimakoshi, Y. Hisaeda, Synthesis and simple separation of b-pyrrole sulfonated porphycenes, Tetrahedron Lett., 10.1016/j.tetlet.2004.06.045, 45, 31, 5973-5975, Vol.45, No.31, 5973-5975, 2004.07.
261. T. Baba, H. Shimakoshi, I. Aritome, Y. Hisaeda, Synthesis and Characterization of シ-Oxodiiron(III) Complexes of Porphycenes with Electron-withdrawing Substituents, Chem. Lett., 10.1246/cl.2004.906, 33, 7, 906-907, Vol.33, No.7, 906-907, 2004.07.
262. H. Shimakoshi, M. Tokunaga, Y. Hisaeda, Hydrophobic Vitamin B12. Part 19. Electroorganic reaction of DDT mediated by hydrophobic vitamin B12, Dalton Trans., 10.1039/b315170k, 6, 878-882, 878-882, 2004.03.
263. Hisashi Shimakoshi, Mami Tokunaga, Yoshio Hisaeda, Hydrophobic vitamin B12· part 19
Electroorganic reaction of DDT mediated by hydrophobic vitamin B12, Dalton Transactions, 6, 878-882, 2004.03, The controlled-potential electrolysis of 1,1-bis(4-chlorophenyl)-2,2,2- trichloroethane (DDT) was carried out at -1.4 V vs. Ag-AgCl in the presence of a hydrophobic vitamin B12, heptamethyl cobyrinate perchlorate. DDT was dechlorinated to form 1,1-bis(4-chlorophenyl)-2,2-dichloroethane (DDD), 1,1-bis(4-chlorophenyl)-2,2-dichloroethylene (DDE), 1-chloro-2,2-bis(4- chlorophenyl)ethylene (DDMU) and 1,1,4,4-tetrakis(4-chlorophenyl)-2,3-dichloro- 2-butene (TTDB) (E/Z), and quantitative recovery of the catalyst after the electrolysis was confirmed by electronic spectroscopy. A photo-sensitive intermediate having a cobalt-carbon bond formed during the electrolysis was characterized by electronic spectroscopy. A mechanism for the formation of various dechlorinated products was investigated by using deuterium solvents and various spectroscopic measurements such as UV-VIS and the EPR spin-trapping technique..
264. H. Sato, T. Hayashi, T. Ando, Y. Hisaeda, T. Ueno, Y. Watanabe, Hybridization of Modified-Heme Reconstitution and Distal Histidine Mutation to Functionalize Sperm Whale Myoglobin, J. Am. Chem. Soc., 10.1021/ja038798k, 126, 2, 436-437, Vol.126, No.2, 436-437, 2004.01.
265. H. Shimakoshi, M. Tokunaga, K. Kuroiwa, N. Kimizuka, Y. Hisaeda, Preparation and electrochemical behaviour of hydrophobic vitamin B12 covalently immobilized onto platinum electrode, Chem. Commun., 10.1039/b309457j, 1, 50-51, 50-51, 2004.01.
266. Takashi Hayashi, Hideaki Sato, Takashi Matsuo, Takaaki Matsuda, Yutaka Hitomi, Yoshio Hisaeda, Enhancement of enzymatic activity for myoglobins by modification of heme-propionate side chains, Journal of Porphyrins and Phthalocyanines, 8, 1-3, 255-264, 2004.01, The modification of myoglobin is an attractive process not only for understanding its molecular mechanism but also for engineering the protein function. The strategy of myoglobin functionalization can be divided into at least two approaches: site-directed mutagenesis and reconstitution with a non-natural prosthetic group. The former method enables us to mainly modulate the physiological function, while the latter has the advantage of introducing a new function on the protein. Particularly, replacement of the native hemin with an artificially created hemin having hydrophobic moieties at the terminal of the heme-propionate side chains serves as an appropriate substrate-binding site near the heme pocket, and consequently enhances the peroxidase and peroxygenase activities for the reconstituted myoglobin. In addition, the incorporation of the synthetic hemin bearing modified heme-propionates into an appropriate apomyoglobin mutant drastically enhances the peroxidase activity. In contrast, to convert myoglobin into a cytochrome P450 enzyme, a flavin moiety as an electron transfer mediator was introduced at the terminal of the heme-propionate side chain. The flavomyoglobin catalyzes the deformylation of 2-phenylpropanal in the presence of NADH under aerobic conditions through the peroxoanion formation from the oxygenated species. In addition, modification of the heme-propionate side chains has an significant influence on regulating the reactivity of the horseradish peroxidase. Furthermore, the heme-propionate side chain can form a metal binding site with a carboxylate residue in the heme pocket. These studies indicate that modification of the heme-propionate side chains can be a new and effective way to engineer functions for the hemoproteins..
267. T. Hayashi, Y. Nakashima, K. Ito, T. Ikegami, I. Aritome, K. Aoyagi, T. Ando, Y. Hisaeda, Synthesis, Characterization and Autoreduction of a Highly Electron-Deficient Porphycenatoiron(III) with Trifluoromethyl Substituents, Inorg. Chem., 10.1021/ic034757d, 42, 23, 7345-7347, Vol.42, No. 23, 7345-7347, 2003.11.
268. T. Hayashi, Y. Nakashima, K. Ito, T. Ikegami, I. Aritome, K. Aoyagi, T. Ando, Y. Hisaeda, Synthesis, Characterization and Autoreduction of a Highly Electron-Deficient Porphycenatoiron(III) with Trifluoromethyl Substituents, Inorg. Chem., 10.1021/ic034757d, 42, 23, 7345-7347, Vol.42, No. 23, 7345-7347, 2003.11.
269. T. Hayashi, Y. Nakashima, K. Ito, T. Ikegami, I. Aritome, A. Suzuki, Y. Hisaeda, Synthesis, Structure and Unique Chemial Property of a First Fluorine-Containing Porphycene, Org. Lett., Vol.5, No.16, 2845-2848, 2003.09.
270. T. Hayashi, Y. Nakashima, K. Ito, T. Ikegami, I. Aritome, A. Suzuki, Y. Hisaeda, Synthesis, Structure and Unique Chemial Property of a First Fluorine-Containing Porphycene, Org. Lett., Vol.5, No.16, 2845-2848, 2003.09.
271. H. Shimakoshi, T. Inaoka, Y. Hisaeda, Solid-solid synthesis of a hydrophobic vitamin B12 having a benzo-18-crown-6 moiety at the C10 position of the corrin ring, Tetrahedron Lett., 10.1016/S0040-4039(03)01587-9, 44, 34, 6421-6424, Vol.44, No.34, 6421-6424, 2003.08.
272. H. Shimakoshi, T. Inaoka, Y. Hisaeda, Solid-solid synthesis of a hydrophobic vitamin B12 having a benzo-18-crown-6 moiety at the C10 position of the corrin ring, Tetrahedron Lett., 10.1016/S0040-4039(03)01587-9, 44, 34, 6421-6424, Vol.44, No.34, 6421-6424, 2003.08.
273. Takashi Hayashi, Yuji Nakashima, Kazuyuki Ito, Takahiro Ikegami, Isao Aritome, Akihiro Suzuki, Yoshio Hisaeda, Synthesis, structure, and chemical property of the first fluorine-containing porphycene, Organic Letters, 10.1021/ol0348452, 5, 16, 2845-2848, 2003.08, [URL], (Matrix presented) A pyrrolic macrocycle, β -tetrakis(trifluoromethyl)porphycene, is the first example of a fluorine-containing porphycene. Four electron-withdrawing CF3 substituents provide a highly distorted structure and an attractive electron-deficient nature for the porphycene framework. From the electrochemical study, it is found that the LUMO energy level for the β-trifluoromethylporphycene is 1.24 V more stabilized compared to that for etioporphyrin. Moreover, the deprotonation of the inner N-H proton in the porphycene was observed upon the addition of DBU..
274. T. Hayashi, T. Matsuo, K. Harada, Y. Hisaeda, S. Hirota, N. Funasaki, Role of Heme-Propionate Side Chains in Myoglobin Function, J. Inorg. Biochem., 10.1016/S0162-0134(03)80489-0, 96, 1, 50-50, Vol.96, 50, 2003.07.
275. H. Shimakoshi, T. Kaieda, T. Matsuo, H. Sato, Y. Hisaeda, Syntheses of new water-soluble dicobalt complexes having two cobalt-carbon bonds and their ability for DNA cleavage, Tetrahedron Lett., 10.1016/S0040-4039(03)01252-8, 44, 28, 5197-5199, Vol.44, No.28, 5197-5199, 2003.07.
276. T. Hayashi, T. Matsuo, K. Harada, Y. Hisaeda, S. hirota, N. Funasaki, Role of Heme-Propionate Side Chains in Myoglobin Function, J. Inorg. Biochem., 10.1016/S0162-0134(03)80489-0, 96, 1, 50-50, Vol.96, 50, 2003.07.
277. H. Shimakoshi, T. Kaieda, T. Matsuo, H. Sato, Y. Hisaeda, Syntheses of new water-soluble dicobalt complexes having two cobalt-carbon bonds and their ability for DNA cleavage, Tetrahedron Lett., 10.1016/S0040-4039(03)01252-8, 44, 28, 5197-5199, 2003.07.
278. T. Hayashi, T. Matsuda, Y. Hisaeda, Enhancement of Peroxygenase Activity of Horse Heart Myoglobin by Modification of Heme-propionate Side Chains, Chem. Lett., 10.1246/cl.2003.496, 32, 6, 496-497, Vol.32, No.6, 496-497, 2003.06.
279. H. Shimakoshi, A. Nakazato, M. Tokunaga, K. Katagiri, K. Ariga, J. Kikuchi, Y. Hisaeda, Hydrophobic Vitamin B12. Part 18. Preparation of a sol-gel modified electrode immobilized with vitamin B12 derivative and its reductive dehalogenation activity, J. Chem. Soc., Dalton Trans., 10.1039/b212863b, 11, 2308-2312, 2308-2312, 2003.06.
280. H. Maeda, A. Osuka, Y. Ishikawa, I Aritome, Y. Hisaeda, H. Furuta, N-Confused Porphyrin-Bearing meso-Perfluorophenyl Groups: A Potential Agent That Forms Stable Square-Planar Complexes with Cu(II) and Ag(III), Org. Lett., 10.1021/ol34227l, 5, 8, 1293-1296, Vol.5, No.8, 1293-1296, 2003.05.
281. Hiromitsu Maeda, Atsuhiro Osuka, Yuichi Ishikawa, Isao Aritome, Yoshio Hisaeda, Hiroyuki Furuta, N-confused porphyrin-bearing meso-perfluorophenyl groups
A potential agent that forms stable square-planar complexes with Cu(II) and Ag(III), Organic Letters, 10.1021/ol034227l, 5, 8, 1293-1296, 2003.04, [URL], (Matrix presented) N-Confused porphyrin (NCP) bearing pentafluorophenyl groups at meso-positions, which were obtained from N-confused dipyrromethane in ca. 20% yield, can form Cu(II) complex as well as Ag(III), Ni(II), and Pd(II) complexes. The square-planar structures of all these metal complexes were elucidated by X-ray single-crystal analyses..
282. F. Tani, M. Matsu-ura, K. Ariyama, T. Setoyama, T. Shimada, S. Kobayashi, T. Hayashi, T. Matsuo, Y. Hisaeda, Y. Naruta, Iron Twin-Coronet Porphyrins as Models of Myoglobin and Hemoglobin: Amphibious Electrostatic Effects of Overhanging Hydroxyl Groups for Successful CO/O2 Discrimination, Chem. Eur. J., 10.1002/chem.200390096, 9, 4, 862-870, Vol.9, No.4, 862-870, 2003.02.
283. H. Shimakoshi, T. Kai, I. Aritome, Y. Hisaeda, Syntheses of Large-membered Macrocycles Having multiple Hydrogen Bonding Moieties, Tetrahedron Lett., 10.1016/S0040-4039(02)02022-1, 43, 46, 8261-8264, Vol.43, No.46, 8261-8264, 2002.10.
284. K. Sakurai, R. Iguchi, K. Koumoto, T. Kimura, M. Mizu, Y. Hisaeda, S. Shinkai, Polysaccharide-Polynucleotide Complexes VIII. Cation-Induced Complex Formation between
Polyuridylic Acid and Schizophyllan, Biopolymers, 10.1002/bip.10189, 65, 1, 1-9, Vol.65, 1-9, 2002.09.
285. T. Hayashi, H. Dejima, T. Matsuo, H. Sato, D. Murata, Y. Hisaeda, Blue Myoglobin Reconstituted with an Iron Porphycene Shows Extremely High Oxygen Affinity, J. Am. Chem. Soc., 10.1021/ja0265052, 124, 38, 11226-11227, Vol.124, No.38, 11226-11227, 2002.09.
286. T. Matsuo, T. Hayashi, Y. Hisaeda, Reductive Activation of Dioxygen by a Myoglobin Reconstituted with a Flavohemin, J. Am. Chem. Soc., 10.1021/ja027291r, 124, 38, 11234-11235, Vol.124, No.38, 11234-11235, 2002.09.
287. I. Aritome, H. Shimakoshi, Y. Hisaeda, 3,6,13,19-Tetrabromo-2,7,12,17-tetrapropylporphycene, Acta Cryst., 10.1107/S0108270102013483, 58, O563-O564, Vol. C58, 563-564, 2002.08.
288. H. Shimakoshi, M. Koga, Y. Hisaeda, Synthesis, Characterization, and Redox Behavior of New Dicobalt Complexes Having Monoanionic Imine/Oxime-type Ligands, Bull. Chem. Soc. Jpn., 10.1246/bcsj.75.1553, 75, 7, 1553-1558, Vol.75, No.7, 1553-1558, 2002.07.
289. T. Hayashi, T. Aya, N. Nonoguchi, T. Mizutani, Y. Hisaeda, S. Kitagawa, H. Ogoshi, Chemical Recognition and Chiral Induction by Use of Zinc Porphyrin Dimers, Tetrahedron, Vol. 58, 2803-2811, 2002.04.
290. Takashi Hayashi, Toshihiro Aya, Masanori Nonoguchi, Tadashi Mizutani, Yoshio Hisaeda, Susumu Kitagawa, Hisanobu Ogoshi, Chiral recognition and chiral sensing using zinc porphyrin dimers, Tetrahedron, 10.1016/S0040-4020(02)00166-7, 58, 14, 2803-2811, 2002.04, [URL], The chiral zinc porphyrin dimer linked by the (S)-NMe2 or (R)-2,2′-dimethoxy-1,1′-binaphthyl tightly binds diamines via a zinc-nitrogen coordinated ditopic interaction. In particular, the zinc porphyrin displays excellent enantioselectivity towards Lys. The D/L selectivity is determined to be 11-12 for the lysine derivatives. The achiral zinc porphyrin dimers linked by biphenyl unit exhibit a significantly induced CD in the Soret region in the presence of chiral diamines such as lysine amides and cystine diesters, indicating that the chirality of the amino acid derivatives can be monitored upon the complexation with the achiral zinc porphyrin dimer. These results conclude that the zinc porphyrin dimers linked by rigid spacers may be good receptors to discriminate two enantiomers or monitor the absolute configuration of a diamine..
291. T. Hayashi, T. Matsuo, Y. Hitomi, K. Okawa, A. Suzuki, Y. Shiro, T. Iizuka, Y. Hisaeda, H. Ogoshi, Contribution of Heme-Propionate Side Chains to Structure and Function of Myoglobin:
Chemical Approach by Artificially Created Prosthetic Groups, J. Inorg. Biochem., 10.1016/S0162-0134(02)00423-3, 91, 1, 94-100, Vol.91, 94-100, 2002.01.
292. T. Hayashi, Y. Hisaeda, New Functionalization of Myoglobin by Chemical Modification of Heme-Propionates, Acc. Chem. Res., 10.1021/ar000087t, 35, 1, 35-43, Vol. 35, 35-43, 2002.01.
293. T. Hayashi, T. Ando, T. Matsuda, H. Sato, T. Matsuo, Y. Hisaeda, Chemical Properties of Reconstituted Myoglobins with Functionalized Hemin Derivatives, J. Inorg. Biochem., 86, 1, 57-57, Vol. 86, No. 1, 57, 2001.08.
294. K. Ariga, K. Tanaka, K. Katagiri, J. Kikuchi, H. Shimakoshi, E. Ohshima, Y. Hisaeda, Langmuir Monolayer of Organoalkoxysilane for vitamin B12-modified Electrode, Physical Chemistry Chemical Physics, 10.1039/b100974p, 3, 16, 3442-3446, Vol. 3, 3442-3446, 2001.08.
295. H. Dejima, T. Hayashi, T. Matsuo, Y. Hisaeda, New Myoglobin Reconstituted with an Iron Porphycene as a Structural Isomer of Heme Moiety, J. Inorg. Biochem., 86, 1, 200-200, Vol. 86, No. 1, 200, 2001.08.
296. T. Ando, T. Hayashi, H. Sato, Y. Hisaeda, Photoinduced Electron Transfer within an Artificially Created Protein-protein Complex, J. Inorg. Biochem., 86, 1, 124-124, Vol. 86, No. 1, 124, 2001.08.
297. T. Hayashi, K. Okazaki, N. Urakawa, H. Shimakoshi, J. L. Sessler, E. Vogel, Y. Hisaeda, Cobaltporphycenes as Catalysts. The Oxidation of Vinyl Ethers via the Formation and Dissociation of Cobalt-Carbon Bonds, Organometallics, 10.1021/om010141p, 20, 14, 3074-3078, Vol. 20, No. 14, 3074-3078, 2001.07.
298. H. Shimakoshi, A. Nakazato, T. Hayashi, Y. Tachi, Y. Naruta, Y. Hisaeda, Electroorganic Syntheses of Macrocyclic Lactones Mediated by Vitamin B12 Model Complexes Part 17. Hydrophobic vitamin B12, J. Electroanal. Chem., 10.1016/S0022-0728(01)00418-1, 507, 1-2, 170-176, Vol. 507, No.1-2, 170-176, 2001.07.
299. H. Shimakoshi, W. Ninomiya, Y. Hisaeda, Reductive Coupling of benzyl Bromide Catalyzed by a Novel Dicobalt Complex Having Two Salen Units, J. Chem. Soc., Dalton Trans., 10.1039/b010022f, 13, 1971-1974, No. 13, 1971-1974, 2001.07.
300. H. Shimakoshi, M. Koga, T. Hayashi, Y. Tachi, Y. Naruta, Y. Hisaeda, Formation and Cleavage of a Dicobalt Complex Bridged with a Pentamethylene Group, Chem. Lett., 10.1246/cl.2001.346, 4, 346-347, No. 4, 346-347, 2001.04.
301. Y. Hitomi, T. Hayashi, K. Wada, T. Mizutani, Y. Hisaeda, H. Ogoshi, Interprotein Electron Transfer Reaction Regulated by an Artificial Interface, Angew. Chem. Int. Ed., 10.1002/1521-3773(20010316)40:6<1098::AID-ANIE10980>3.0.CO;2-G, 40, 6, 1098-+, Vol. 40, No. 6, 1098-1101, 2001.03.
302. Hisashi Shimakoshi, W. Ninomiya, Yoshio Hisaeda, Reductive coupling of benzyl bromide catalyzed by a novel dicobalt complex having two salen units, Journal of the Chemical Society, Dalton Transactions, 13, 1971-1974, 2001.01, A novel dicobalt complex[CoII2L] has been synthesized, where (L)4- is a dinucleating ligand derived by the 2: 2: 1 condensation of ethylenediamine, salicylaldehyde, and 5,5′-methylenebis(salicylaldehyde), and it has two N2O2 metal-binding sites which are linked to each other with a methylene spacer. This complex was characterized by UV-VIS, IR, and NMR as well as mass spectroscopy. Its redox behavior was investigated in dmf using cyclic voltammetry in comparison with that for the corresponding mononuclear complex [Co(salen)]. The redox couples to CoIII-CoII and CoII-CoI for [CoII2L] were observed at +0.09 and - 1.20 V vs. Ag-AgCl, respectively. These potentials are quite similar to those for [Co(salen)]. The electro-generated [CoI2- reacts with alkyl halide at each metal center to give an organocobalt complex. A further one-electron reduction of the compound yields an unstable intermediate that undergoes rapid decomposition by cleavage of the cobalt-carbon bond. The electrolysis of benzyl bromide at - 1.40 V vs. Ag-AgCl in the presence of the dicobalt complex yields bibenzyl as the major product. On the other hand, when [Co(salen)] was used as a catalyst, toluene was obtained as the major product. The difference in the product distribution is due to the structural properties of the catalysts..
303. T. Hayashi, T. Ando, T. Matsuda, H. Yonemura, S. Yamada, Y. Hisaeda, Introduction of a Specific Binding Domain on Myoglobin Surface by New Chemical Modification, J. Inorg. Biochem., 10.1016/S0162-0134(00)00153-7, 82, 1-4, 133-139, Vol. 82, 133-139, 2000.12.
304. Hideki Kobayashi, Kazuaki Nakashima, Eiji Ohshima, Yoshio Hisaeda, Itaru Hamachi, Seiji Shinkai, Novel saccharide-induced conformational changes in a boronic acid-appended poly(L-lysine) as detected by circular dichroism and fluorescence, Journal of the Chemical Society. Perkin Transactions 2, 5, 997-1002, 2000.05, Poly(L-lysine) has been modified with a 4-phenylboronic acid derivative which acts as a sugar-binding site and a dansyl group which acts as a fluorescence probing site. The helix content of this poly(L-lysine) derivative as estimated by CD spectroscopy became maximum at pH 10.3. The helix content was increased from 51 to 79% by complexation of D-fructose with the pendant boronic acid group and the maximum pH shifted from 10.3 to 7.9. Examination of the CD spectra revealed that the conformation changes in the order of β-sheet → α-helix → random coil with increasing medium pH. The D-glucose addition induced a similar increase in the helix content and a similar low pH shift of the helix content maximum but the mechanism was somewhat different: one D-glucose was bound to two boronic acid groups to form an intrapolymeric bridge and the resultant CD spectrum was similar to that of the β-turn structure. These saccharide-induced conformational changes were well reflected by plots of fluorescence intensity vs. pH. The decrease in the fluorescence intensity in the high pH region (random coil region) was confirmed by fluorescence polarization to be due to the increase in the molecular motion. This is a novel system to control the poly(amino acid) conformation by saccharides and to detect the conformational changes by convenient spectroscopic methods..
305. Y. Hisaeda, T. Nishioka, Y. Inoue, K. Asada, T. Hayashi, Electrochemical Reactions Mediated by Vitamin B12 Derivatives in Organic Solvents, Coordination Chemistry Review, 10.1016/S0010-8545(99)00222-2, 198, 21-37, Vol. 198, No. 1, 21-37, 2000.04.
306. T. Hayashi, K. Okazaki, H. Shimakoshi, F. Tani, Y. Naruta, Y. Hisaeda, Synthesis and Properties of Alkylperoxocobalt(III) Porphyrin and Porphycene, Chem. Lett., 2, 90-91, No.2, 90-91, 2000.02.
307. H. Shimakoshi, M. Tokunaga, K. Kuroiwa, N. Kimizuka, Y. Hisaeda, Preparation and electrochemical behaviour of hydrophobic vitamin B12 covalently immobilized onto platinum electrode, Chem. Commun., 10.1039/b309457j, 1, 50-51, 50-51, 2000.01.
308. Yoshio Hisaeda, Artificial enzymes based on supramolecular chemistry, Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme, 45, 15, 2483-2492, 2000.01.
309. Katsuhiko Ariga, Keizo Tanaka, Kiyofumi Katagiri, Jun Ichi Kikuchi, Eiji Ohshima, Yoshio Hisaeda, Syntheses and monolayer properties of vitamin B12 derivatives with seven alkyl chains, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/S0927-7757(00)00416-7, 169, 1-3, 47-58, 2000.01, [URL], The heptapropyl and heptaoctyl esters of vitamin B12 derivatives with a Co(II) or Co(III) center have been synthesized and their monolayer properties have been investigated. The effect of the esters' chain length on stability and orientation of the vitamin B12 in a lipid monolayer is discussed on the basis of their surface pressure molecular area (π-A) isotherms. Their isotherms significantly depend on the length of the side chains regardless of the oxidation state of the center cobalt. The isotherm of the heptaoctyl derivatives has a relatively steep shape with a molecular area of ca. 3 nm2 which is fairly close to the molecular area estimated by molecular modeling for face-on orientation. In contrast, the heptapropyl derivatives showed unstable characteristics with collapsing even at low pressures. The heptaoctyl derivatives can also be stably incorporated in the DPPC matrix monolayer, while the heptapropyl derivatives were squeezed out from the same matrix upon compression at high pressures. The effect of coordination of the center cobalt to the matrix lipid was also investigated. Mixing of the heptapropyl Co(II) derivatives with a lysine-functionalized lipid significantly improved the preservation of the vitamin B12 function in the monolayer due to coordination of the lysine amino group to the open axial position of Co(II). The obtained results in this study indicate that stable accommodation of the vitamin B12 functions in the lipid assembly can be achieved by the introduction of a long chain and/or coordination to the matrix lipid. The present study is the first example of a monolayer system of vitamin B12 mimics with a core structurally identical to the naturally occurring one..
310. Takashi Hayashi, Kenshi Okazaki, Hisashi Shimakoshi, Fumito Tani, Yoshinori Naruta, Yoshio Hisaeda, Synthesis and properties of alkylperoxocobalt(III) porphyrin and porphycene, Chemistry Letters, 10.1246/cl.2000.90, 2, 90-91, 2000.01, [URL], Alkylcobalt(III) and alkylperoxocobalt(III) species of porphyrin and porphycene have been prepared and characterized by UV-vis and 1H NMR spectroscopic measurements. Thermal decomposition of the alkylperoxocobalt species proceeds via Co-O or O-O bond cleavage, which depends on the coordination of an axial ligand..
311. T. Hayashi, Y. Hitomi, T. Takimura, A. Tomokuni, T. Mizutani, Yoshio Hisaeda, H. Ogoshi, New approach to the construction of an artificial hemoprotein complex, Coordination Chemistry Reviews, 10.1016/S0010-8545(99)00131-9, 190-192, 961-974, 1999.12, [URL], Modified prosthetic metalloporphyrin, having a total of eight carboxylate groups at the terminal of two peripheral propionate side chains, was inserted into apomyoglobin to yield a new reconstituted myoglobin. The cluster of substituted carboxylates acts as the binding domain for cationic compounds such as methyl viologen and cytochrome c. Fluorescence spectroscopic analysis indicates that the reconstituted myoglobin formed a stable complex with methyl viologen and photoinduced singlet electron transfer (ET) occurred within the complex; k(et) = 2.1 x 109 s-1 and k(cr) = 3.3 x 108 s-1. Cytochrome c with a positively charged domain also interacted with the reconstituted myoglobin with an association constant of 6.5 x 104 M-1. The photoinduced triplet ET from the zinc reconstituted myoglobin to ferricytochrome c occurred through diprotein complex with a rate constant of 2.2 x 103 s-1. Furthermore, compared to native myoglobin, the ferryl state of the reconstituted myoglobin generated by hydrogen peroxide revealed the peroxidase activity with the acceleration of the oxidation of ferrocytochrome c via complex formation. The present approach could be very useful for constructing practical protein-protein complex systems to elucidate the biological ET via noncovalently linked biomolecules. (C) 1999 Elsevier Science S.A..
312. T. Hayashi, Y. Hitomi, T. Ando, T. Mizutani, Y. Hisaeda, S. Kitagawa, H. Ogoshi, Peroxidase Activity of Myoglobin Is Enhanced by Chemical Mutation of Heme-Propionates, J. Am. Chem. Soc., 10.1021/ja9841005, 121, 34, 7747-7750, Vol. 121, No.34, 7747-7750, 1999.09.
313. T. Hayashi, Y. Hitomi, T. Takimura, A. Tomokuni, T. Mizutani, Y. Hisaeda, T.Ogoshi, New Approach to the Construction of Artificial Hemoprotein Complex, Coordination Chemistry Review, 192, 961-974, Vol. 190, pp.961-974, 1999.09.
314. T. Hayashi, Y. Hitomi, Y. Hisaeda, S. Kitagawa, Enhancement of Peroxidase Activity by Use of Reconstituted Myoglobin, J. Inorg. Biochem., 74, 1-4, 156-156, Vol. 74, No. 1-4, p.156, 1999.07.
315. T. Hayashi, A. Tomokuni, T. Mizutani, Y. Hisaeda, H. Ogoshi, Interfacial Recognition between Reconstituted Myoglobin Having Charged Binding Domain and Electron Acceptor via Electrostatic Interaction, Chemistry Letters, 10.1246/cl.1998.1229, 12, 1229-1230, No.12, pp.1229-1230, 1998.12.
316. A. Tanaka, S. Shimada, T. Hirohashi, T. Hayashi, Y. Hisaeda, Molecular Recognition by Novel Macrotetracyclic Cyclophanes Having Dipeptide Segments, Chemistry Letters, 10.1246/cl.1998.1109, 11, 1109-1110, No.11,pp.1109-1110, 1998.11.
317. Y. Hisaeda, A. Ogawa, T. Ohno, Y. Murakami, Hydrophobic Vitamin B12. Part 15. Carbon-skeleton Rearrangement Reactions Mediated by Hydrophobic Vitamin B12 Covalently Bound to an Anionic Lipid Species in Aqueous Media, Inorganica Chimica Acta,, 10.1016/S0020-1693(97)06036-2, 273, 1-2, 299-309, Vol.273, No.1-2, pp.299-309, 1998.05.
318. A. Tanaka, S. Fujiyoshi, K. Motomura, O. Hayashida, Y. Hisaeda, Y. Murakami, Preparation and Host-Guest Interactions of Novel Cage-type Cyclophanes Bearing Chiral Binding Sites Provided by Dipeptide Residues, Tetrahedron, 10.1016/S0040-4020(98)00218-X, 54, 20, 5187-5206, Vol.54, No.20, pp.5187-5206, 1998.05.
319. Yoshio Hisaeda, Akihiro Ogawa, Teruhisa Ohno, Yukito Murakami, Hydrophobic vitamin B
12
. Part 15
1
. Carbon-skeleton rearrangement reactions mediated by hydrophobic vitamin B
12
covalently bound to an anionic lipid species in aqueous media, Inorganica Chimica Acta, 273, 1-2, 299-309, 1998.05, A novel artificial vitamin B
12
holoenzyme was prepared in aqueous media by combination of a hydrophobic vitamin B
i2
covalently bound to an anionic lipid species and a bilayer matrix of sodium N,N-dihexadecyl-N
α
-(6-sulfohexanoyl)-L-alaninamide. Microenvironmental properties around a hydrophobic vitamin B
12
placed in the bilayer membrane were examined by electronic spectroscopy and fluorescence polarization measurements. The hydrophobic vitamin B
12
was well separated from a bulk aqueous phase, and its molecular motion was markedly suppressed. A reaction mimicking catalytic functions of methylmalonyl-CoA mutase was carried out by using hydrophobic vitamin B
12
derivatives having a diethyl 2,2-bis(ethoxycarbonyl)propyl group at an axial site of the nuclear cobalt. A carbon-skeleton rearrangement of the alkyl ligand bound to a hydrophobic vitamin B
12
was markedly promoted in the bilayer matrix, relative to the reaction in methanol and benzene, via formation of a radical intermediate. A reaction simulating catalysis by α-methyleneglutarate mutase was also carried out. The cyanide ion enhanced a carbon-skeleton rearrangement of the 2,3-bis(ethoxycarbonyl)-l-butene moiety bound to hydrophobic vitamin B
12
derivatives in the bilayer membrane under photolysis conditions via formation of an anionic intermediate. As an extension of such mimicking reactions, a carbon-skeleton rearrangement reaction of diethyl 2-acetylamino-2-methylpropanedioate coordinated to a hydrophobic vitamin B
12
covalently bound to a lipid species, which afforded diethyl 2-acetylaminobutanedioate, was also examined in the bilayer membrane under photolysis conditions. The motional repression and desolvation effects operated on the substrate-bound hydrophobic vitamin B
12
were found to be responsible for enhancement of the rearrangement reactions of the substrate radicals formed under photolysis conditions..
320. Aga Hirohide, Akiko Aramata, Yoshio Hisaeda, The electroreduction of carbon dioxide by macrocyclic cobalt complexes chemically modified on a glassy carbon electrode, Journal of Electroanalytical Chemistry, 437, 1-2, 111-118, 1997.11, Various macrocyclic cobalt complexes were chemically bonded to a glassy carbon (GC) electrode, on which CO2 electroreduction was carried out to give CO in aqueous phosphate buffer solution of pH 6.3. The macrocyclic cobalt complexes were naphthalocyanato cobalt(II), phthalocyanato cobalt(II), dibromo(11-hydroxyimino-4,10-dipropyl-5,9-diazatrideca-4,9-dien-3-one oximato) cobalt(III) (denoted as CoDO), two kinds of hydrophobic vitamin B12s (heptamethyl cobyrinate perchlorate and heptapropyl cobyrinate perchlorate), 5,10,15,20-tetraphenylporphyrinato cobalt(II), and 5,10,15,20-tetrakis (4-methoxyphenyl)porphyrinato cobalt(II). Their redox potentials of Co(I)/Co(II) are in the above order from positive to negative potentials in a 0.05 M TBAP DMSO solution, being between -0.23 and -1.0 V (SCE). These complexes were chemically bonded to GC through -CONH-pyridine which locates perpendicularly to a planar or semi-planar complex structure, where the N of the pyridine forms a coordinate bond with the Co atom of the above complexes as a fifth ligand. The catalytic activity for hydrogen evolution in aqueous solution was observed to be high on Co naphthalocyanine and Co phthalocyanine modified GC electrodes; the latter gave H2 evolution at the most positive potentials among the Co complexes employed. When the lower potential limit in cyclic voltammetry became less than the hydrogen evolution potential, in the reverse positive-going sweep, an anodic hump current was observed at -0.35 ∼ -0.78 V, which is assigned to a cobalt hydride oxidation process; the hydride is suggested to form when hydrogen evolution takes place, and the hump disappeared after the introduction of CO2 into the solution. It was observed that the Co complex chemically bonded on GC can give CO from CO2 only at relatively low overvoltages, except for CoDO which was not able to reduce CO2; phthalocyanato cobalt(II) gave CO at E = -1.0 V (0.26 V as overvoltage) at 20% current efficiency. The highest CO current efficiency was observed in the case of tetraphenyl-porphyrinato cobalt(II) chemically modified GC..
321. Yoshio Hisaeda, Eiji Ohshima, Jun Ichi Kikuchi, Yukito Murakami, Preparation of artificial glycolipids and their aggregation behavior in aqueous media, Tetrahedron Letters, 10.1016/S0040-4039(97)01572-4, 38, 38, 6713-6716, 1997.09, [URL], N,N-Dihexadecyl-N(α)-[6-(β-D-galactopyranosyl)hexanoyl]-L-alaninamide and N,N- dihexadecyl-N(α)-[6{(β-D-galactopyranosyl)-(1→4)-O-(D -glucopyranosyl)}hexanoyl]-L-alaninamide, which have an amino acid residue interposed between a polar sugar moiety and a hydrophobic double-chain segment individually, were prepared and characterized as novel artificial glycolipids. Morphological studies by means of differential scanning calorimetry and dynamic light scattering as well as electron microscopy clarified that these lipids tend to form stable bilayer membranes by themselves in aqueous media..
322. Osamu Hayashida, Akinori Tanaka, Setsuko Fujiyoshi, Yoshio Hisaeda, Yukito Murakami, Host-guest interactions of cage-type cyclophanes bearing chiral binding sites provided by dipeptide residues, Tetrahedron Letters, 10.1016/S0040-4039(97)00021-X, 38, 7, 1219-1222, 1997.02, [URL], Novel cage-type cyclophanes, which are constructed with two rigid macrocyclic skeletons, tetraaza[3.3.3.3]paracyclophanes, and four bridging segments composed of β-L-aspartyl-L-aspartyl residues and β-D-aspartyl-D-aspartyl residues individually, were prepared. Chiral host-guest interactions between the hosts and a hydrophobic guest, pamoic acid, were examined by circular dichroism spectroscopy in aqueous media..
323. Yoshio Hisaeda, Junji Takenaka, Yukito Murakami, Hydrophobic vitamin B12. Part 14. Ring-expansion reactions catalyzed by hydrophobic vitamin B12 under electrochemical conditions in nonaqueous medium, Electrochimica Acta, 10.1016/S0013-4686(97)85494-1, 42, 13-14, 2165-2172, 1997.01, [URL], The electrolysis of alicyclic ketones (5, 6, 7, and 8-membered rings) with a carboxylic ester and a bromomethyl group was carried out in N,N-dimethylformamide in the presence of a catalytic amount of heptamethyl cobyrinate perchlorate under various reaction conditions. The ring-expansion reaction largely proceeded at -2.0 V vs sce for all the substrates. The electrolysis plausibly proceeds as follows: the Co(II) complex as a catalyst is electrochemically reduced to the Co(I) species; the corresponding alkylated complex is generated by reaction of the supernucleophilic Co(I) species with an alicyclic bromide; the alkylated complex is subsequently decomposed by electrolysis to afford the final products; and the cobalt complex acts as a mediator repeatedly..
324. Yoshio Hisaeda, Electroorganic Reactions Mediated by Vitamin B12 Model Complexes, Yuki Gosei Kagaku Kyokaishi/Journal of Synthetic Organic Chemistry, 54, 10, 63-71, 1996.12, Vitamin B12-dependent enzymes, involving the cobalt species as a catalytic center, mediate various isomerization reactions accompanied by carbon-skeleton rerragements. In order to simulate the catalytic functions of vitamin B12 as excerted in the hydrophobic active sites of enzymes concerned, we have been dealing with hydrophobic vitamin B12 derivatives which have ester groups in place of the peripheral amide moieties of the naturally occurring vitamin B12. In this work, the carbon-skeleton rearrangements as mediated by hydrophobic vitamin B12 derivatives were investigated under electrochemical conditions. The controlled-potential electrolyses of alkyl halides with various electron-withdrawing groups were carried out, and the electrochemical carbon-skeleton rearrangements proceeded effectively via formation of anionic intermediates. These reactions can be also applied to the ring-expansin reactins. We have carried out the electrolysis of an alkyl halide having two ester groups and one phenyl group on the β-carbon atom in the presence of a catalytic amount of the hydrophobic vitamin B12. The migration of the pheny group was observed under the conditions forming a radical intermediate. The ester-migrated product was detected under the conditions forming an anionic intermediate. This is the first successful example in selecting a migrating group by electroylsis potential. We have also prepared a strapped hydrophobic vitamin B12 in order to change the enantioselectivity. The controlled-potential electrolysis of a racemic alkyl halide having phenyl, methoxy, and carboxylic ester groups on the same carbon atom was carried out. The simple hydrophobic vitamin B12 tends to bind S-enantiomers more favorably. On the other hand, strapped hydrophobic vitamin B12 acts to bind R-enantiomers more favorably. These results suggested that the stability of alkylated complexes was dominated the enantioselectivity of reduction products..
325. Yoshio Hisaeda, Electroorganic reactions mediated by vitamin B12 model complexes, Yuki Gosei Kagaku Kyokaishi/Journal of Synthetic Organic Chemistry, 54, 10, 859-867, 1996.10, It is shown that vitamin B12-dependent enzymes; involving the cobalt atoms as a catalytic center, mediate various isomerization reactions accompanied by carbon skeleton rearrangements. The rearrangements were investigated using the hydrophobic vitamin B12 derivatives under electrochemical conditions. As shown, the electrochemical carbon-skeleton rearrangements proceed via formation of anionic intermediates during the electrolysis of alkyl halides with various electron-seeking groups. The data suggest that the migration of a phenyl group on the β-carbon atom results in the formation of a radical intermediate. The enantiomer type is shown to be dependent on the hydrophobic vitamin B12 nature..
326. Yukito Murakami, Jun Ichi Kikuchi, Yoshio Hisaeda, Osamu Hayashida, Artificial enzymes, Chemical Reviews, 10.1021/cr9403704, 96, 2, 721-758, 1996.01, [URL].
327. Osamu Hayashida, Akinori Tanaka, Koji Motomura, Yoshio Hisaeda, Yukito Murakami, Preparation and characterization of novel cage-type cyclophanes having three or four bridging dipeptide segments, Chemistry Letters, 10.1246/cl.1996.1057, 12, 1057-1058, 1996.01, [URL], Novel cage-type cyclophanes constructed with two rigid macrocyclic skeletons, triaza[3.3.3]paracyclophanes or tetraaza-[3.3.3.3]paracyclophanes, and three or four dipeptide moieties, α-L-aspartyl-L-aspartyl residues, were prepared. The guest-binding behavior of the cage-type hosts toward fluorescent guests, such as 8-anilinonaphthalene-1-sulfonate and 6-p-toluidinonaphthalene-2-sulfonate, was examined in comparison with that demonstrated by non-cage hosts toward the identical guests..
328. Yukito Murakami, Yoshio Hisaeda, Akihiro Ogawa, Teruhisa Ohno, Carbon-skeleton rearrangement of an amino acid derivative as mediated by hydrophobic vitamin B
12
covalently bound to a lipid species in a bilayer membrane, Journal of the Chemical Society, Perkin Transactions 2, 2, 189-191, 1995.12, Diethyl 2-acetylamino-2-methylpropanedioate co-ordinated to a hydrophobic vitamin B
12
covalently bound to a peptide lipid underwent a carbon-skeleton rearrangement to afford diethyl 2-acetylaminobutanedioate in the single-walled vesicle of N,N-bis(hexadecyl)-Nα-(6-sulfohexanoyl)-L- alaninamide under photolysis conditions..
329. Osamu Hayashida, Tomoko Hirohashi, Yoshio Hisaeda, Yukito Murakami, Preparation and characterization of water-soluble cyclophanes bearing three or four dipeptide moieties as cationic hosts, Tetrahedron Letters, 10.1016/0040-4039(95)01705-M, 36, 44, 8051-8054, 1995.10, [URL], Water-soluble cyclophanes bearing dipeptide residues were prepared by stepwise condensation of 2.11.20.29-tetraaza[3.3.3.3]paracyclophane or 2,11,20-triaza[3.3.3]paracyclophane with l-valinc and l-lysine in this sequence and their conformalional changes upon complexation with a hydrophobic guest were examined by circular dichroism spectroscopy..
330. Osamu Hayashida, Kazuya Ono, Yoshio Hisaeda, Yukito Murakami, Specific molecular recognition by chiral cage-type cyclophanes having leucine, valine, and alanine residue, Tetrahedron, 10.1016/0040-4020(95)00458-K, 51, 31, 8423-8436, 1995.07, [URL], Chiral cage-type cyclophanes were constructed with two rigid macrocyclic skeletons and four bridging components bearing chiral leucine, valine, and alanine residues, individually. These host molecules strongly bind anionic and hydrophobic guests, such as 8-anilinonaphthalene-1-sulfonate and 6-p-toluidinonaphthalene-2-sulfonate. Thermodynamic parameters were evaluated from temperature-dependent complexation constants determined by fluorescence spectroscopy, and gave negative ΔH and positive ΔS values; especially large values for the cage-type cyclophanes having leucine residues. The positive ΔS values come primarily from effective desolvation of the guest molecules when incorporated into the hydrophobic host cavities, as evidenced by fluorescence parameters. The four bridging segments of the cage-type hosts having chiral amino acid residues seem to undergo chiral twist in the same directions in the light of circular dichroism (CD) spectroscopy. Such helical conformations of the cyclophanes must be caused by chiral nature of the amino acid residues, and the extent of twist in helical conformations is as follows; leucine > valine > alanine. In addition, the twisted direction of bridging segments in the cage-type hosts having L-amino acid residues is opposite to that evaluated for those having D-amino acid residues, so that the former and latter cyclophanes furnish M- and P-helical cavities, respectively. The chirality-based molecular recognition of the cage-type hosts toward an enantiomeric guest, bilirubin-IXα, was investigated by CD spectroscopy in aqueous media..
331. Jonathan L. Sessler, Steven J. Weghorn, Yoshio Hisaeda, Vincent Lynch, Hexaalkyl Terpyrrole
A New Building Block for the Preparation of Expanded Porphyrins, Chemistry – A European Journal, 10.1002/chem.19950010110, 1, 1, 56-67, 1995.01, [URL], A new, general synthesis of the first β‐substituted tetra‐ and hexaalkyl terpyrroles is described. Also described are two new classes of expanded porphyrins derived from the hexaalkyl terpyrrole. The key step in the terpyrrole formation is the copper(II)‐mediated oxidative coupling of the LDA‐derived enolates of α‐keto pyrroles. The first new expanded porphyrin reported here, the so‐called “orangarin”, contains five pyrrolic subunits and two bridging carbon atoms, and is formally a 20π‐electron nonaromatic macrocycle. The second new class of expanded porphyrins, the “amethyrins”, are 24π‐electron nonaromatic macrocycles containing six pyrrole units. Both of these new macrocycles, as well as one of the new terpyrrolic precursors have been structurally characterized by single crystal X‐ray diffraction analysis..
332. Yukito Murakami, Yoshio Hisaeda, Teruhisa Ohno, Hiroshi Kohno, Takuya Nishioka, Hydrophobic vitamin B12. Part 12. Preparation, characterization and enantioselective alkylation of strapped hydrophobic vitamin B12, Journal of the Chemical Society, Perkin Transactions 2, 6, 1175-1183, 1995, Cyanocobalamin has been modified to afford a strapped hydrophobic vitamin B12 by introducing a 1,3-phenylenediacetyl moiety into the peripheral site of the corrin's B ring. The modified complex was characterized by various spectroscopic methods and cyclic voltammetry in comparison with the corresponding data for a simple hydrophobic vitamin B12 without a strapping moiety. The alkylation of hydrophobic vitamin B12 derivatives with racemic 3-bromo-2-methylpropionic esters at the β-axial site was carried out in methanol, and extents of the enantioselectivity were examined by 1H NMR spectroscopy. The strapped hydrophobic vitamin B12 and a simple hydrophobic vitamin B12 were found to react with (S)-3-bromo-2-methylpropionates more readily than the corresponding R-enantiomers; the highest S-selectivity (75% ee) was observed with the strapped hydrophobic vitamin B12. The 5-enantioselectivity was discussed from a stereochemical viewpoint based on the conformational search for the alkylated hydrophobic vitamin B12 by means of molecular mechanics and dynamics calculations..
333. Teruhisa Ohno, Akihiro Ogawa, Yoshio Hisaeda, Yukito Murakami, Isomerization of an axial ligand coordinated to hydrophobic vitamin B12 as effected by cyanide ion and microenvironment, Tetrahedron Letters, 10.1016/0040-4039(94)88518-4, 35, 51, 9589-9592, 1994.12, [URL], The cyanide ion enhanced a carbon-skeleton rearrangement of the 2,3-bis(ethoxycarbonyl)-1-butene moiety bound to hydrophobic vitamin B12 derivatives in single-compartment bilayer vesicles under photolysis conditions via formation of the anionic substrate intermediate..
334. Teruhisa Ohno, Takuya Nishioka, Yoshio Hisaeda, Yukito Murakami, Hydrophobic vitamin B12. Part 13. Asymmetric reaction of hydrophobic vitamin B12 under electrochemical conditions and rationalization of enantioselectivity based on conformational analysis, Journal of Molecular Structure: THEOCHEM, 10.1016/0166-1280(94)80103-7, 308, C, 207-218, 1994.05, [URL], The controlled-potential electrolysis of racemic ethyl 3-bromo-2-methoxy-2-phenylpropionate was carried out at -1.8V vs. SCE in N,N-dimethylformamide, as mediated by a simple hydrophobic vitamin B12, [Cob(II)7C3ester]ClO4, and a strapped hydrophobic vitamin B12, [Cob(II)(c,10-PDA)6C3ester]ClO4, to afford ethyl 2-methoxy-2-phenylpropionate and ethyl 2-methoxy-3-phenylpropionate in the dark. The simple hydrophobic vitamin B12 acted to afford ethyl (S)-2-methoxy-2-phenylpropionate, the hydrogen-substituted product, in 55% e.e., while the strapped hydrophobic vitamin B12 was in favor of formation of the corresponding R enantiomer in 26% e.e. Since the reaction proceeds via formation of an intermediate in which the ethyl 2-methoxy-2-phenylpropionate moiety is bound to the hydrophobic vitamin B12, the chiral microenvironment provided by the peripheral groups placed around the corrin framework is responsible for the enantioselective formation of the alkylated hydrophobic vitamin B12. The enantioselective coordination of the substrate species was rationalized by means of molecular mechanics and dynamics computations as well as by Monte Carlo conformational search; the simple hydrophobic vitamin B12 with the S substrate is lower in energy than the complex with the R substrate by l.8 kJ mol-1, while the strapped hydrophobic vitamin B12 with the R substrate is lower than the identical complex with the S substrate by 2.0 kJ mol-1..
335. M. Tabata, K. Kaneko, Y. Murakami, Yoshio Hisaeda, H. Mimura, Fluorometric Determination of Trace Amounts of Fluoride Ion Using an Expanded Porphyrin, Microchemical Journal, 10.1006/mchj.1994.1021, 49, 2-3, 136-144, 1994.04, [URL], A highly selective and sensitive method of fluorometry is described for determination of the fluoride ion at the parts per billion level via the ion-pair complex formation of the fluoride ion with an expanded prophyrin [2,23-diethyl-8,17-bis(2-ethoxycarbonylethyl)-3,7,12,13,18,22-hexamethyl sapphyrin (H
3
sap)]. The ion-pair complex gives out an enhanced fluorescence intensity at 680 nm on excitation at 450 nm. Since the present method is based on a direct reaction of the fluoride ion with the sappyrin, a 200-fold amount of the aluminum (III) ion [10
-4
M (M = mol dm
-3
)] and a 2000-fold amount of the iron(III) ion (10
-3
M) over the fluoride ion did not interfere with determination of the fluoride ion at concentrations as low as 5 × 10
-7
M in the presence of 1,2-diaminocyclohexane-N,N,N′,N′-teraacetic acid. The proposed method was applied to determination of the fluoride ion in various water samples (tap water, river water, rain water, underground water, and hot spring water) and satisfactory results were obtained..
336. Teruhisa Ohno, Akihiro Ogawa, Yoshio Hisaeda, Yukito Murakami, Isomerization catalysis by hydrophobic vitamin B12 covalently bound to a lipid species in a bilayer membrane, Journal of the Chemical Society, Perkin Transactions 1, 11, 2271-2273, 1994, A novel artificial vitamin B12 holoenzyme composed of a hydrophobic vitamin B12 covalently bound to a lipid species and a bilayer matrix of sodium N,N-dihexadecyl-Nα-(6-sulfohexanoyl)-L-alaninamide enhanced a methylmalonyl-CoA mutase model reaction..
337. Yukito Murakami, Yoshio Hisaeda, Akihiro Ogawa, Tetsuya Miyajima, Osamu Hayashida, Teruhisa Ohno, Aggregation behavior and reactivity of hydrophobic vitamin B12 covalently bound to lipid in aqueous media, Tetrahedron Letters, 10.1016/0040-4039(93)89033-M, 34, 5, 863-866, 1993.01, [URL], A mixture of a hydrophobic vitamin B12 covalently bound to a lipid species and N,N-dihexadecyl-Nα- [6-(trimethylammonio)hexanoyl]-L-alaninamide bromide at a 1 : 50 molar ratio afforded stable single-compartment vesicles by sonication, which provided an anaerobic microenvironment in aqueous media under aerobic conditions..
338. Yukito Murakami, Osamu Hayashida, Toshihiro Ito, Yoshio Hisaeda, Molecular recognition by novel cage-type azaparacyclophanes bearing chiral binding sites in aqueous media, Pure and Applied Chemistry, 10.1351/pac199365030551, 65, 3, 551-556, 1993.01, [URL], Novel cage-type cyclophanes which are constructed with two rigid macrocyclic skeletons, tetraaza[6.1.6.1]paracyclophane and tetraaza[3.3.3.3]-paracyclophane, and four chiral bridging components were prepared. An asymmetric character of the internal cavity was clarified by means of circular dichroism (CD) spectroscopy and a computer-aided molecular modeling study based on molecular mechanics and dynamics (BIOGRAF, Dreiding-I and Dreiding-II) conformational search. In aqueous media, the present hosts strongly bound anionic and nonionic hydrophobic guests to form inclusion complexes in 1:1 stoichiometry and the CD phenomena were induced in an incorporated achiral guest molecule through its stereochemical interaction with the chiral host cavity. In addition, the present hosts exhibited discriminative recognition toward steroid hormones in D2O/CD3OD (3:1 v/v) as effected by hydrophobic and π-π interactions. The chirality-based discrimination of estrogens was attributed to their different modes of hydrogen bonding with the hosts..
339. Yukito Murakami, Osamu Hayashida, Kazuya Ono, Yoshio Hisaeda, Thermodynamical and geometrical characterization of molecular recognition by cage-type and peptide azapara-cyclophanes in aqueous media, Pure and Applied Chemistry, 10.1351/pac199365112319, 65, 11, 2319-2324, 1993.01, [URL], A cage-type cyclophane which is constructed with two rigid macrocyclic skeletons, tetraaza[6.1.6.1]paracyclophane and tetraaza[3.3.3.3]paracyclophane, and four chiral bridging components strongly binds anionic and hydrophobic guests, such as 8-anilinonaphthalene-1-sulfonate and 6-p-toluidinonaphthalene-2-sulfonate. Thermodynamic parameters were evaluated from temperature-dependent complexation constants for the cage-type host and a peptide cyclophane, which was prepared by introducing four valine residues into a tetraaza[6.1.6.1]-paracyclophane skeleton, with the hydrophobic guests as determined by fluorescence spectroscopy. The complexation of the former and latter hosts with the guests gave positive and negative AS values, respectively. The positive AS values come primarily from effective desolvation of the guest molecule incorporated into the hydrophobic host cavity and partly from conformational changes around the bridging moieties of the cage-type host upon complexation, as evidenced by fluorescence polarization and circular dichroism measurements. The geometrical arrangements of the guest molecules in the respective inclusion complexes were clarified by detailed 1H NMR analysis..
340. Yoshio Hisaeda, Takeshi Ihara, Teruhisa Ohno, Yukito Murakami, Yonezo Maeda, Azaparacyclophanes with metal-binding sites. Part 1. Preparation, characterization, and molecular recognition behaviour of hexapus azaparacyclophane and its iron(III) complex, Journal of the Chemical Society, Perkin Transactions 2, 4, 595-604, 1992.12, All the catechol moieties of a hexapus triaza[3.3.3]paracyclophane having three catechol moieties and six hydrocarbon chains (1) undergo coordination interactions with the iron(III) ion in a 1:1 molar ratio of 1 to iron(III) above pH 6 in an aqueous medium. Two different iron(III) complexes of 1, A and B in a 1:1 molar ratio, are in the high spin iron(in) state as characterized by electronic, EPR and Mössbauer spectroscopy: A is a hexacoordinated mononuclear complex with half-protonated catecholato groups, subjected to considerable structural distortion; B is a hexa-coordinated mononuclear complex with complete dissociation of all the catechol protons, retaining high structural symmetry. The molecular recognition behaviour of 1 and Fe-complex A toward hydrophobic guest molecules has been investigated in aqueous HEPES and acetate buffers at 30.0 °C and μ 0.10 mol dm-3. The hexapus cyclophane 1 recognizes organic guests through hydrophobic and electrostatic interactions; anionic and non-ionic guests, 7-hydroxy-8-phenylazonaphthalene-1, 3-disulfonate (OG) and 2-hydroxy-1-(2-pyridylazo)naphthalene (PAN), respectively, are incorporated into host 1 with binding constants of the order of 105 dm3 mol-1, while a cationic guest, 2-(p-dimethylaminostyryl)-1-ethylquinolinium (QR), is not included in the host. The guest-binding behaviour of Fe-complex A toward OG and PAN is much enhanced relative to that of 1 as effected by hydrophobic, electrostatic and coordination interactions under conditions identical to those applied to 1; the binding constant for OG is nearly pH-independent in a pH range of 3-8, while that for PAN is pH-dependent because the coordination interaction with the host is subject to change by pH..
341. Yukito Murakami, Yoshio Hisaeda, Xi Ming Song, Teruhisa Ohno, A migrating group in a glutamate mutase model reaction mediated by a functionalised bilayer membrane, Journal of the Chemical Society, Perkin Transactions 2, 9, 1527-1528, 1992, The alkylated hydrophobic vitamin B12, prepared by the reaction of heptapropyl cobyrinate with diethyl β-bromomethyl-β-deuterio-DL- aspartate, affords diethyl γ-deuterioglutamate, the glycylmigrated product in the single-compartment vesicle of N,N-dihexadecyl-Nα-[6- (trimethylammonio)hexanoyl]-L-alaninamide bromide under anaerobic photolysis conditions..
342. Y. Murakami, Yoshio Hisaeda, H. Kohno, T. Ohno, T. Nishioka, Hydrophobic vitamin B12. XI. Preparation, characterization, and enantioselective alkylation of hydrophobic vitamin B12 bearing a binaphthyl moiety, Bulletin of the Chemical Society of Japan, 10.1246/bcsj.65.3094, 65, 11, 3094-3102, 1992, [URL].
343. Yukito Murakami, Yoshio Hisaeda, Teruhisa Ohno, Hydrophobic vitamin B12. Part 9. An artificial holoenzyme composed of hydrophobic vitamin B12 and synthetic bilayer membrane for carbon-skeleton rearrangements, Journal of the Chemical Society, Perkin Transactions 2, 3, 405-416, 1991.12, The incorporation of hydrophobic vitamin B12 derivatives, which have ester groups in place of the peripheral amide moieties of the naturally occurring vitamin B12, into single-compartment vesicles composed of synthetic lipids having an alanyl residue in the single-chain segment, is primarily controlled by the hydrophobicity of the peripheral ester groups. Such incorporation into vesicles of another synthetic lipid, having a histidyl residue in place of an alanyl residue, was much enhanced when coordination was allowed to take place between the nuclear cobalt of the hydrophobic vitamin B12 and the imidazolyl moiety of the lipid. Microenvironmental properties around heptapropyl cobyrinate derivatives placed in single-compartment vesicles of the former lipid were examined by electronic, fluorescence and fluorescence polarization measurements as well as by differential scanning calorimetry. The hydrophobic vitamin B12 was incorporated into the intramembrane domain composed of assembly of the single-chain segment of each lipid molecule, and its molecular motion was markedly suppressed under such microenvironmental conditions. Carbon-skeleton rearrangement reactions of alkyl ligands bound to heptapropyl cobyrinate were markedly favoured in the single-compartment vesicle, relative to the reactions in methanol and benzene, under anaerobic photolysis conditions at ordinary temperatures. The 1,2-migration of electron-withdrawing groups, such as acetyl, cyano, carboxylic ester and thioester, apparently arises both from suppression of molecular motion and desolvation effects operating on the alkylated hydrophobic vitamin B12 in the vesicle. Finally, the catalytic mediator, constituted with heptapropyl cobyrinate perchlorate and the single-compartment vesicle in aqueous media, was coupled with a substrate-activation system, composed of atmospheric oxygen and vanadium(in) ions, to establish a real artifical holoenzyme. 2-Acetyl-2- ethoxycarbonylpropane, 2-cyano-2-ethoxycarbonylpropane and 1-acetyl-1- ethoxycarbonylethane were converted catalytically into the corresponding rearrangement products under aerobic photolysis conditions at 20°C. A plausible reaction mechanism for the catalytic reaction is discussed..
344. Yukito Murakami, Jun Ichi Kikuchi, Teruhisa Ohno, Takayuki Hirayama, Yoshio Hisaeda, Hiroshi Nishimura, James P. Snyder, Kosta Steliou, Yukito Murakami, Jun Ichi Kikuchi, Teruhisa Ohno, Takayuki Hirayama, Yoshio Hisaeda, Hiroshi Nishimura, Jun Ichi Kikuchi, James P. Snyder, Kosta Steliou, Syntheses of Macrocyclic Enzyme Models. 8.

Conformational Mobility and Molecular Recognition by the Internal Cage of Kyuphane, Journal of the American Chemical Society, 10.1021/ja00022a006, 113, 22, 8229-8242, 1991.10, [URL], Temperature-dependent
1
H NMR measurements in CDC1
3
−CS
2
(3:7 v/v) and DMF-d
7
in concert with MM2 conformational analysis reveal that the molecular framework of “Kyuphane” (1), a cage-type cubical molecule with six faces each consisting of a 2, 1l,20, 29-tetraaza[3.3.3.3]paracyclophane ring, is significantly more rigid than the corresponding noncage host (2), but still conformationally flexible. A slow rate of interconversion among degenerated conformers of the lowest energy C, conformation accounts for the observed NMR line broadening. Hosts 1 and 2 are soluble in acidic aqueous media below pH 4 and behave as polycationic species. Electrostatic field solvation analysis of the tetraprotonated salt of Kyuphane suggests a square-planar proton placement (11a) to predominate in solution. Line broadening for the tetracation appears to arise from both conformer interconversion and proton exchange. Guest recognition behavior of these hosts under acidic conditions was studied by means of
1
H NMR and fluorescence spectroscopy. Kyuphane demonstrates a pH-dependent guest-binding ability due to changes in the specific microenvironmental polarity of its three-dimensional cavity upon variable protonation of the nitrogen atoms. The host also shows size-sensitive and regioselective molecular discrimination originating from the semirigid geometry of the hydrophobic cavity and the specific protonation geometry. The specific molecular discrimination evidenced by 1 was analyzed by MM2 molecular mechanics and applied to selective transport of hydrophobic molecules between organic phases across an aqueous phase in which 1 was present as a carrier. It is noteworthy that the proton NMR signals of guest molecules naphthalene-2,6-disulfonate, 8-anilinonaphthalene-l-sulfonate, and 6-p-toluidinonaphthalene-2-sulfonate completely disappear upon complexation with Kyuphane, whereas the identical guest naphthalene-2,6-disulfonate shows normal upfield shifts of its NMR proton signals upon complexation with 2..
345. Yukito Murakami, Yoshio Hisaeda, Toshiaki Ozaki, Hydrophobic vitamin B12. X.F steric effect in electrochemical carbon-skeleton rearrangement catalyzed by hydrophobic vitamin B12in nonaqueous media, Journal of Coordination Chemistry, 10.1080/00958979109408244, 23, 1-4, 77-89, 1991.06, [URL], A steric effect in the carbon-skeleton rearrangement catalyzed by heptamethyl cobyrinate perchlorate, [Cob(II)7C1ester]ClO4, was investigated under electrochemical conditions. The controlled-potential electrolyses of alkyl halides having two carboxylic ester groups of different bulkiness on the same carbon atom, such as 2, 2-bis(ethoxycarbonyl)-l-bromopropane, I-bromo-2-tert-butoxycarbonyl-2-ethoxycarbonylpropane l-bromo-2-cyclohexyloxycarbonyl-2-ethoxycarbonylpropane, and l-bromo-2-ethoxy-carbonyl-2-phenoxycarbonylpropane, were carried out in N, N-dimethylformamide, as catalyzed by [Cob(II)7C1ester]ClO4 to give the corresponding ester-migrated products in the dark at — 1.5 V vs SCE in the presence of acetic acid and at —2.0 V vs SCE without acetic acid. As regards a correlation between bulkiness of an ester group and a migration aptitude, a smaller ester group tends to migrate to the adjacent carbon atom more readily than a larger one. The origin of such a steric effect is discussed with attention to the rate-determining step..
346. Yukito Murakami, Teruhisa Ohno, Osamu Hayashida, Yoshio Hisaeda, Novel cage-type azaparacyclophane bearing chiral binding sites, Journal of the Chemical Society, Chemical Communications, 10.1039/C39910000950, 14, 950-952, 1991, [URL], The guest-binding behaviour of a novel cage-type azaparacyclophane, which has been prepared by the reaction of N,N′,N″,N‴-tetravalyl-1, 6,20,25-tetraaza[6.1.6.1]paracyclophane with N,N′,N″,N‴- tetrakis(5-carboxynicotinoyl)-2,11,20,29-tetraaza[3.3.3.3]paracyclophane, was examined in aqueous media and evaluated by a computer-aided molecular modelling study on the basis of molecular mechanics (MM2 and MMP2) and molecular dynamics (AMBER and CHARMM) conformational search..
347. Yukito Murakami, Jun Ichi Kikuchi, Yoshio Hisaeda, Koichiro Nakamura, Tomoyuki Kitazaki, Hidenori Kaya, Functionalized bilayer membranes as artificial tryptophan synthase. Characterization of catalytic efficiency, substrate specificity, and reaction selectivity, Bulletin of the Chemical Society of Japan, 10.1246/bcsj.63.2339, 63, 8, 2339-2345, 1990.08, [URL], Functionalized bilayer membranes having vitamin B6 activity effectively catalyzed β-replacement reactions of serine with indoles to afford the corresponding tryptophan derivatives in aqueous media under mild conditions. Catalytic capability of the present artificial enzyme was subjected to change by changing a combination of molecular components constituting the catalyst system. The structural mode of a hydrophobic pyridoxal derivative as the coenzyme model, the catalytic ability of an amino acid residue placed in a peptide lipid which forms single-walled bilayer vesicles as the apoenzyme model, and the coordination property of added metal ions were found to be responsible for the overall catalytic performance. Multifunctional assistance was observed in the β-replacement reaction of serine with indole, and the reaction proceeded in preference to other side reactions, such as β-elimination, dealdolation, and transamination reactions. Substrate selectivity was found to be primarily dependent on the nucleophilicity of indole derivatives..
348. Yukito Murakami, Yoshio Hisaeda, Teruhisa Ohno, Hydrophobic vitamin B12. VII. ring-expanison reactions catalyzed by hydrophobic vitamin B12 in octopus azaparacyclophane, Journal of Coordination Chemistry, 10.1080/00958979009408178, 21, 1, 13-22, 1990.01, [URL], Ring-expansion reactions of alkyl ligands bound to heptapropyl cobyrinate at the axial site of the nuclear cobalt were found to be markedly favoured in the hydrophobic cavity of an octopus azaparacyclophane, relative to reactions in methanol and benzene, under anaerobic photolysis conditions at 20.0°C. Heptapropyl cobyrinate perchlorate catalyzed the same ring-expansion reactions, which convert 2-methyl-1,3-cydopentanedione and 3-methyl-2-pyrrolidinone into 1,4-cyclohexanedione and 2-piperidinone, respectively, in the octopus cyclophane by utilizing vanadium trichloride as a co-catalyst under aerobic photolysis conditions..
349. Yukito Murakami, Yoshio Hisaeda, Teruhisa Ohno, Hydrophobic vitamin B12. 8. Carbon-skeleton rearrangement reactions catalyzed by hydrophobic vitamin B12 in octopus azaparacyclophane, Bioorganic Chemistry, 10.1016/0045-2068(90)90015-W, 18, 1, 49-62, 1990.01, [URL], Heptapropyl cobyrinate perchlorate catalyzed the carbon-skeleton rearrangements, which convert 2-acetyl-2-ethoxycarbonylpropane, 2-cyano-2-ethoxycarbonylpropane, 1-acetyl-1-ethoxycarbonylethane, and diethyl β-methyl-dl-aspartate into 1-acetyl-2-ethoxycarbonylpropane, 2-cyano-1-ethoxycarbonylpropane and 1-cyano-2-ethoxycarbonylpropane, 1-acetyl-2-ethoxycarbonylethane, and diethyl glutamate, respectively, in an octopus cyclophane placed in aqueous carbonate buffer (pH 7.0) at 20.0°C by utilizing vanadium trichloride as a cocatalyst under aerobic photolysis conditions. The migratory aptitude of the electron-withdrawing groups was found to follow the sequence: CN ≈ CO2C2H5 < COCH3. Yields of the rearrangement products were very low in the absence of heptapropyl cobyrinate perchlorate..
350. Yoshio Hisaeda, Takeshi Ihara, Teruhisa Ohno, Yukito Murakami, Preparation and molecular recognition behavior of a hexapus azaparacyclophane, Tetrahedron Letters, 10.1016/S0040-4039(00)94421-6, 31, 7, 1027-1030, 1990.01, [URL], The proton dissociation, iron-coordination, and molecular recognition behavior of a hexapus triaza[3.3.3]paracyclophane having three catechol moieties and six hydrocarbon chains was investigated in aqueous media..
351. Yukito Murakami, Yoshio Hisaeda, Toshiaki Ozaki, Yoshihisa Matsuda, Electrochemical carbon-skeleton rearrangements catalysed by hydrophobic vitamin B12 immobilised in a polymer-coated electrode, Journal of the Chemical Society, Chemical Communications, 10.1039/C39890001094, 16, 1094-1096, 1989, [URL], A glassy carbon electrode was coated with a polymer species derived from a hydrophobic vitamin B12 and Araldite CT-200,and the immobilised cobalt complex catalysed the electrochemical carbon-skeleton rearrangements of alkyl halides having electron-withdrawing groups..
352. Yukito Murakami, Yoshio Hisaeda, Jun Ichi Kikuchi, Teruhisa Ohno, Masashi Suzuki, Yoshihisa Matsuda, Takeo Matsuura, Hydrophobie vitamin B12. Part 6. † Carbon-skeleton rearrangement via formation of Host-guest complexes derived from an 'Octopus' azaparacyclophane and hydrophobie vitamin B12 derivatives
A novel holoenzyme model system, Journal of the Chemical Society, Perkin Transactions 2, 10.1039/P29880001237, 7, 1237-1246, 1988.01, [URL], The alkylation reactions of a hydrophobic vitamin B12 derivative with alkyl bromides in an 'octopus' azaparacyclophane having eight hydrocarbon chains have been investigated. Molecular discrimination has been shown to originate from electrostatic interaction between the octopus cyclophane and the alkyl bromides. Alkylation was enhanced by desolvation and proximity effects operating on the reacting species via formation of a ternary complex composed of the octopus cyclophane, the hydrophobic vitamin B12 derivative, and an alkyl halide. Carbon-skeleton rearrangement reactions of alkyl ligands bound to the hydrophobic vitamin B12 were found to be markedly favoured in the hydrophobic cavity provided by the octopus cyclophane, relative to the reactions in methanol and benzene, under anaerobic photolysis conditions at ordinary temperatures. The same reactions took place readily in solid benzene below 4 °C under similar conditions. The central cobalt atom of the hydrophobic vitamin B12 participates in the rearrangement reaction via formation of a tight pair with an alkyl radical species. Nonenzymic rearrangement reactions have been shown here to proceed quite efficiently by employing a relevant apoenzyme model..
353. Yukito Murakami, Yoshio Hisaeda, Novel Catalytic Functions of Hydrophobic Vitamin B12 in Electrochemical Carbon-Skeleton Rearrangements, Pure and Applied Chemistry, 10.1351/pac198860081363, 60, 8, 1363-1368, 1988.01, [URL], The carbon-skeleton rearrangements as catalyzed by hydrophobic vitamin B12 derivatives were investigated under electrochemical conditions. The controlled-potential electrolyses of alkyl halides with various electron-withdrawing groups were carried out, and the electrochemical carbon-skeleton rearrangements proceeded via formation of anionic intermediates. Substrates with two electron-withdrawing groups placed on the β-carbon atom with combination of one carboxylic ester and one of carboxylic ester, ace-tyl, and cyano moieties readily gave the corresponding rearrangement products which were derived from individual migration of the substituent groups. Substrates with only one of the electron-withdrawing groups, carboxylic ester, acetyl, and cyano, did not give any rearrangement product, but a substrate with one thioester group afforded the corresponding rearrangement product. The apparent migratory aptitude of electron-withdrawing groups was found to decrease in the order: COSR > COR > CO2R > CN. A hydrophobic vitamin B12 with the cyano moiety at the axial site of cobalt further enhanced the electrochemical carbon-skeleton rearrangement..
354. Yukito Murakami, Yoshio Hisaeda, Toshiaki Ozaki, Teruhisa Ohno, Yutaro Tani, Preparation and Reactivity of Hydrophobic Vitamin B12 Derivatives Having an Intramolecular Axial Base, NIPPON KAGAKU KAISHI, 10.1246/nikkashi.1988.445, 1988, 4, 445-451, 1988.01, [URL], In order to clarify crucial roles of an intramolecular axial base in alkylation and dealkylation reactions of vitamin B12, hydrophobic vitamin B12 derivatives bearing a proximal base capable of coordinating to the nuclear cobalt at the α - and β-sites, [Cob(II)(α -Im)6 C1ester]ClO4 and [Cob(II)(β -Im)6 C2ester]C1O4, respectively, and a hydrophobic vitamin B12 capped with a fragment involving the imidazolyl moiety, [Cob(II)(Im: cap)5 C1ester]C1O4, were prepared. Their ESR spectra indicated that the three different imidazolyl moieties were completely coordinated to the nuclear cobalt, and such intramolecular coordination acted to shift the Co(II)/Co(I) redox potential to a cathodic side. The extent of potential shift was comparable to that observed upon addition of N-methylimidazole to a hydrophobic vitamin B12 without an axial base at a 50: 1 molar ratio. The axial base did not significantly show a kinetic effect on the alkylation of hydrophobic vitamin B12s, since the univalent cobalt has no detectable tendency to interact with an axial ligand. The imidazolyl segment introduced into the β-site inhibited alkylation reactions due to steric reasons. All the intramolecular axial bases treated in this study enhanced cleavage of the cobalt-carbon bond under aerobic irradiation conditions as originated from their steric and electronic effects..
355. Yukito Murakami, Yoshio Hisaeda, Teruhisa Ohno, A synthetic bilayer membrane functionalised with hydrophobic vitamin B 12 as an artificial glutamate mutase, Journal of the Chemical Society, Chemical Communications, 10.1039/C39880000856, 13, 856-858, 1988, [URL], Heptapropyl cobyrinate perchlorate catalysed the conversion of diethyl β-methylaspartate into diethyl glutamate in single-compartment vesicles in the presence of vanadium trichloride as a co-catalyst under aerobic irradiation conditions..
356. Y. Murakami, Yoshio Hisaeda, Hydrophobic vitamin B12. IV. Addition reactions of alcohols to olefins as catalyzed by hydrophobic vitamin B12 derivatives, Bulletin of the Chemical Society of Japan, 10.1246/bcsj.58.2652, 58, 9, 2652-2658, 1985.01, [URL].
357. Y. Murakami, Yoshio Hisaeda, T. Ohno, Hydrophobic vitamin B12. III. Incorporation of hydrophobic vitamin B12 derivatives into single-compartment vesicles and their alkylation in various molecular aggregates, Bulletin of the Chemical Society of Japan, 10.1246/bcsj.57.2091, 57, 8, 2091-2097, 1984, [URL], The incorporation of hydrophobic vitamin B12 derivatives into the single-compartment vesicles of N'N,-didodecyl-N(α)-[6-(tyimethylammonio)hexanoyl]-L-alaninamide bromide (N+C5Ala2C12) was found to be primarily concerned with the extent of insolubility of the cobalt complexes in the aqueous bulk phase, while such incorporation into the single-walled vesicles of N,N-ditetradecyl-N(α)-[6-(trimethylammonio)hexanoyl]-L-histidinamide bromide (N+C5His2C14) was enhanced by the coordination interaction between the cobalt complex and the imidazolyl group of the lipid. In molecular aggregates formed with hexadecyltrimethylammonium bromide, α-[4-(1,1,3,3-tetramethylbutyl)phenyl]-ω-hydroxypoly(oxyethylene), or N+C5Ala2C12, the alkylation rates of a hydrophobic vitamin B12 with 1-bromo-2-methylpropane and methyl 2-methyl-3-bromopropanoate were much enhanced relative to those in methanol. In the N+C5Ala2C12 vesicle, a two-step mechanism was observed for the alkylation with the latter reagent. The possible origin of such rate enhancement was discussed..
358. Y. Hisaeda, H. Shimakoshi, M. Tokunaga, T. Hayashi, Electrochemical reactions mediated by hydrophobic vitamin B12, J. Porphyrins Phthalocyanines, Vol.8, 397.

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