| 1. |
Zhi Zhang, Taro Koide, Zihan Zhou, Hisashi Shimakoshi, Yoshio Hisaeda, Redox behavior of iridium octaethylporphycene and electrocatalytic hydrogen evolution, Journal of Porphyrins and Phthalocyanines, 10.1142/S108842462150053X, 26, 06N07, 434-442, 2022.06, The electrochemical properties of β-octaethylporphycene iridium complex (Ir-OEPo) were determined. Based on the electro-spectro measurement results, the reduction of Ir-OEPo did not occur at the central metal but at the ligand, while the reduction of β-octaethylporphyrin iridium complex (Ir-OEPor) occurred at the central iridium. A catalytic current was observed during the cyclic voltammetry (CV) measurements with trifluoroacetic acid (TFA) under a reductive condition, indicating the catalytic reactivity of Ir-OEPo for the hydrogen evolution reaction (HER). By constant potential electrolysis, hydrogen gas was detected by gas chromatography (GC) and the catalytic reactivity of Ir-OEPo was confirmed. The HER mechanism via ligand reduction of macrocyclic aromatic complexes could be one of the concepts for the development of new catalysts.. |
| 2. |
Zihan Zhou, ＠Taro Koide, Yoshihito Shiota, Yoshio Yano, Ning Xu, Toshikazu On, ＠Hisashi Shimakoshi, Kazunari Yoshizawa, ＠Yoshio Hisaeda, Synthesis, redox properties, and catalytic hydrogen gas generation of porphycene cobalt complexes, Journal of Porphyrins and Phthalocyanines, 10.1142/S108842462250016X, 263–272, 2022.03. |
| 3. |
Zhi Zhang, Taro Fujioka, Taro Koide, Yoshio Yano, Toshikazu Ono, Yoshio Hisaeda, Synthesis of First Antimony Porphycene and Electrocatalytic Hydrogen Evolution Driven by Ligand-Centered Reduction, BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 10.1246/bcsj.20210177, 94, 8, 2048-2053, 2021.08, For post-transition metal electrocatalytic hydrogen evolution reaction (HER), the new porphycene antimony complexes, Sb(III)OEPo and Sb(V)OEPo-Br-2, were synthesized and characterized. Based on the electrochemical and electro-spectro measurements, the two-step one-electron reduction processes of Sb(III)OEPo were indicated to be both ligand-centered and the irreversible reduction process observed for Sb(V)OEPo-Br-2 was assigned to be the reduction from Sb(V)OEPo-Br-2 to Sb(III)OEPo. Electrocatalytic HER proceeded at -1.0 V (vs. Ag/AgCl) under acidic conditions via the ligand-centered reductions. The electron accepting nature of the porphycene ligand enabled the utilization of a main-group element as a central element for the ligand-centered HER at anodically shifted potentials.. |
| 4. |
Zhi Zhang, Taro Fujioka, Taro Koide, Yoshio Yano, Toshikazu Ono, Yoshio Hisaeda, Synthesis of First Antimony Porphycene and Electrocatalytic Hydrogen Evolution Driven by Ligand-Centered Reduction, Bulletin of the Chemical Society of Japan, 10.1246/bcsj.20210177, 94, 2048-2053, 2021.06. |
| 5. |
Zhi Zhang, ＠Taro Koide, Zihan Zhou, ＠Hisashi Shimakoshi, ＠Yoshio Hisaeda, Redox behavior of iridium octaethylporphycene and electrocatalytic hydrogen evolution, Journal of Porphyrins and Phthalocyanines, 10.1142/S108842462150053X, in press, 2021.04. |
| 6. |
Kohei Ishihama, Toshikazu Ono, Toru Okawara, Takunori Harada, Kiyonao Furusho, Masashi Hasegawa, Yuki Nojima, Taro Koide, Masaaki Abe, Yoshio Hisaeda, Dinuclear Triple-Stranded Helicates Comprising Al(III), Ga(III), or In(III) and a Hydrazine-Linked Bisiminopyrrolyl Ligand: Synthesis, Structure, Optical Resolution, and Chiroptical Properties, Bulletin of the Chemical Society of Japan, 10.1246/bcsj.20200327, 94, 573-578, 2020.11. |
| 7. |
Tsuyoshi Murata, Taro Koide, Hirofumi Nobukuni, Ryotaro Tsuji, Yasushi Morita , 2D Coordination Network of Trioxotriangulene with Multiple Redox Abilities and Its Rechargeable Battery Performance, International Journal of Molecular Sciences, 10.3390/ijms21134723, 21, 4723-4737, 2020.07. |
| 8. |
Taro Koide, Shohei Iwamori, Satoshi Koga, Yasutaka Suzuki, Jun Kawamata, Yoshio Hisaeda, Synthesis of 2,6,9-substituted xanthen-3-one and solvent effect on structural and photophysical properties, Dyes and Pigments, accepted, 2020.07. |
| 9. |
Tsuyoshi Murata, Taro Koide, Hirofumi Nobukuni, Ryotaro Tsuji, Yasushi Morita, 2D Coordination Network of Trioxotriangulene with Multiple Redox Abilities and Its Rechargeable Battery Performance, INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES, 10.3390/ijms21134723, 21, 13, 2020.07, A three-fold symmetric trioxotriangulene derivative with three pyridyl groups as coordinating sites was designed and synthesized. In a cyclic voltammetry measurement, the trioxotriangulene skeleton exhibited a multi-stage redox ability from neutral radical to radical tetra-anion species. In the zinc complex of monoanion species, three pyridyl groups coordinated to the zinc ion to build up a two-dimensional coordination network with a cavity larger than 12 angstrom in diameter. This complex was utilized as a cathode active material of a lithium ion battery, and it exhibited a capacity of ca. 60 mAh g(-1)per the weight of the active material with a stable cycling performance up to 1000 cycles. This work shows that the coordination network formed by the trioxotriangulene-based ligand was effective in the improvement of cycle performance of the organic rechargeable battery.. |
| 10. |
Taro Koide, Takafumi Maeda, Tsukasa Abe, Yoshihito Shiota, Yoshio Yano, Toshikazu Ono, Kazunari Yoshizawa, Yoshio Hisaeda, Mechanistic Study on Ring-Contracting Skeletal Rearrangement from Porphycene to Isocorrole by Experimental and Theoretical Methods, EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, 10.1002/ejoc.201901659, 2020, 12, 1811-1816, 2020.03, In this study, the ring contracting skeletal rearrangement reaction in one-pot under basic conditions from octaethylporphycene to two types of isocorroles, i.e., the meso-formyl and meso-free forms, was confirmed and the reaction mechanism was proposed by the comparative analyses of the experimental and theoretical studies. The electron accepting nature of the porphycene and imine-amine conversion of pyrrole rings make it possible to react with hydroxide ions and the following reaction to afford isocorroles. Based on this reaction, the valence of the compound as a ligand as well as the photochemical and electrochemical properties were dramatically changed.. |
| 11. |
Taro Koide, Zihan Zhou, Ning Xu, Yoshio Yano, Toshikazu Ono, Zhongli Luo, Hisashi Shimakoshi, Yoshio Hisaeda, Electrochemical properties and catalytic reactivity of cobalt complexes with redox-active meso-substituted porphycene ligands, JOURNAL OF PORPHYRINS AND PHTHALOCYANINES, 10.1142/S1088424619500780, 24, 1-3, 90-97, 2020.01, The cobalt complexes of meso-aryl substituted porphycenes were synthesized and characterized. The reduction potentials of the complexes were shifted to the positive side depending on the strength of the electron-withdrawing properties of the meso-substituents, while the optical properties, such as the absorption spectra of these complexes, were similar. This suggests that the energy levels of the molecular orbitals of the complexes were changed by the meso-substituents while the gaps of the orbitals were not significantly changed. The one-electron reduction of the complex did not afford the Co(I) species, but the ligand-reduced radical anion, which was characterized by electrospectrochemistry. The generated ligand-reduced species reacted with alkyl halides to form the Co(III)-alkyl complex. As a result, the reduction potential of the electrolytic reaction could be directly controlled by the substituents of the porphycene. The catalytic reaction with trichloromethylbenzene was also performed and it was found that the ratio of the obtained products was changed by the reduction potentials of the catalyst, i.e. the cobalt porphycenes.. |
| 12. |
Taro Koide, Takafumi Maeda, Tsukasa Abe, Yoshihito Shiota, Yoshio Yano, Toshikazu Ono, Kazunari Yoshizawa, Yoshio Hisaeda, Mechanistic Study on Ring-Contracting Skeletal Rearrangement from Porphycene to Isocorrole by Experimental and Theoretical Methods, European Journal of Organic Chemistry, 10.1002/ejoc.201901659, 1811-1816, 2019.12. |
| 13. |
＠Taro Koide, Zihan Zhou, Ning Xu, Yoshio Yano, ＠Toshikazu Ono, Zhongli Luo, ＠Hisashi Shimakoshi, ＠Yoshio Hisaeda, Electrochemical Properties and Catalytic Reactivity of Cobalt Complexes with Redox-Active meso-Substituted Porphycene Ligands, Journal of Porphyrins and Phthalocyanines, 10.1142/s1088424619500780, 24, 91-97, 2019.06. |
| 14. |
＃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, The Royal Society of Chemistry, 10.1039/c8dt03743d, 47, 872-881, 2019.01. |
| 15. |
Koichi Hashimoto, Taro Koide, Toru Okawara, Hisashi Shimakoshi, Yuta Hori, Yoshihito Shiota, Kazunari Yoshizawa, Yoshio Hisaeda, Redox behaviour of the beta-dihydroporphycene cobalt complex: study on the effect of hydrogenation of the ligand, DALTON TRANSACTIONS, 10.1039/c8dt03743d, 48, 3, 872-881, 2019.01, 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 beta-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.. |
| 16. |
Taro Koide, Isao Aritome, Tatsuya Saeki, Yoshitsugu Morita, Yoshihito Shiota, Kazunari Yoshizawa, Hisashi Shimakoshi, and Yoshio Hisaeda, Cobalt−Carbon Bond Formation Reaction via Ligand Reduction of Porphycene−Cobalt(II) Complex and Its Noninnocent Reactivity, ACS Omega, American Chemical Society, 10.1021/acsomega.8b00239, 3, 4027-4034, 2018.04. |
| 17. |
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, 2018.04, 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 N-2 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 S(N)2-type Co-C bond formation. This result provides us the possibility of the reaction triggered by the reduction of ligand with macrocyclic pi-conjugated system, not by the reduction of metal..  |
| 18. |
Taro Koide, Moritaka Takesue, Toshihiro Murafuji, Koichiro Satomi, Yasutaka Suzuki, Jun Kawamata, Kengo Terai, Mitsuharu Suzuki, Hiroko Yamada, Yoshihito Shiota, Yoshizawa Kazunari, Fumito Tani, An Azulene-Fused Tetracene Diimide with a Small HOMO-LUMO Gap, ChemPlusChem, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, 10.1002/cplu.201600356, 82, 1010-1014, 2017.07, 4つのアズレンが縮環したテトラセンジイミドの合成に成功し、その興味深い物性を明らかにした。π共役系の効果的な拡張と分子内電荷移動によって末端が１４００
nmにまで及ぶ近赤外吸収、950 nmにおいて大きな2光子吸収断面積（σ（2） = 2140 GM）を示した。 この化合物の魅力的な電子特性として、4つの可逆還元プロセスとn型半導性も確認された。. |
| 19. |
Taro Koide, Moritaka Takesue, Toshihiro Murafuji, Koichiro Satomi, Yasutaka Suzuki, Jun Kawamata, Kengo Terai, Mitsuharu Suzuki, Hiroko Yamada, Yoshihito Shiota, Kazunari Yoshizawa, Fumito Tani, An Azulene-Fused Tetracene Diimide with a Small HOMO-LUMO Gap, CHEMPLUSCHEM, 10.1002/cplu.201600356, 82, 7, 1010-1014, 2017.07, A newly prepared tetraazulene-fused tetracene diimide (TA-fused TDI) showed absorption in the near-IR region owing to the effective extension of the pi-conjugated system as well as a large two-photon absorption cross-section (sigma((2)) = 2140 GM) at 950 nm. Four reversible reduction processes and n-type semi-conductivity were also confirmed as attractive electronic properties of this compound.. |
| 20. |
Yousuke Ooyama, Toshiaki Enoki, Joji Ohshita, Takuya Kamimura, Shuwa Ozako, Taro Koide, Fumito Tani, Singlet oxygen generation properties of an inclusion complex of cyclic free-base porphyrin dimer and fullerene C60, RSC Advances, The Royal Society of Chemistry, 10.1039/c7ra02699d, 7, 18690-18695, 2017.03. |
| 21. |
Yousuke Ooyama, Toshiaki Enoki, Joji Ohshita, Takuya Kamimura, Shuwa Ozako, Taro Koide, Fumito Tani, Singlet oxygen generation properties of an inclusion complex of cyclic free-base porphyrin dimer and fullerene C-60, RSC ADVANCES, 10.1039/c7ra02699d, 7, 30, 18690-18695, 2017.03, To gain insight into the singlet oxygen (O-1(2)) generation properties of supramolecular complexes of cyclic free-base porphyrin dimer with fullerene C-60, we evaluated the O-1(2) quantum yield (Phi(Delta)) and rate constant (K-obs) of O-1(2) generation for a cyclic free-base porphyrin dimer (CPD) linked by butadiyne bearing four 4-pyridyl groups and its inclusion complex (C-60 subset of CPD) with C-60. We demonstrate that CPD and C-60 subset of CPD possess the ability to generate O-1(2) under visible light irradiation. Moreover, it was found that the Phi(Delta) value of C-60 subset of CPD is lower than that of CPD. Based on the kinetic and thermodynamic consideration concerning the electron transfer processes between the porphyrin dimer and C-60, this work revealed that the lower Phi(Delta) value of the C-60 inclusion complex would be attributed to the formation of the charge-separated state C-60(.-)-CPD.+, leading to a low intersystem crossing (ISC) efficiency for the formation of the triplet excited state (3)(CPD)*.. |
| 22. |
Yousuke Ooyama, Takuya Kamimura, Shuwa Ozako, Masahiro Kanda, Taro Koide, Fumito Tani, Dye-sensitized solar cell based on an inclusion complex of a cyclic porphyrin dimer bearing four 4-pyridyl groups and fullerene C60, RSC Advances, The Royal Society of Chemistry, 10.1039/c6ra01131d, 6, 16150-16158, 2016.02. |
| 23. |
Yousuke Ooyama, Koji Uenaka, Takuya Kamimura, Shuwa Ozako, Masahiro Kanda, Taro Koide, Fumito Tani, Dye-sensitized solar cell based on an inclusion complex of a cyclic porphyrin dimer bearing four 4-pyridyl groups and fullerene C-60, RSC ADVANCES, 10.1039/c6ra01131d, 6, 20, 16150-16158, 2016.02, Cyclic free-base porphyrin dimers (H-4-C-4-CPDPy(TEO) and H-4-Ptz-CPDPy(TEO)) linked by butadiyne or phenothiazine bearing four 4-pyridyl groups and their inclusion complexes (C-60 subset of H-4-C-4-CPDPy(TEO) and C-60 subset of H-4-Ptz-CPDPy(TEO)) with fullerene C-60 have been applied to dye-sensitized solar cells (DSSCs) as a new class of porphyrin dye sensitizers with pyridyl anchoring groups for attachment on a TiO2 electrode. The FTIR spectra of the porphyrin dimers adsorbed on TiO2 nanoparticles demonstrated that these porphyrin dimers are adsorbed on the TiO2 surface through the formation of hydrogen bonding of pyridyl groups and/or pyridinium ions at Bronsted acid sites on the TiO2 surface. The adsorption amount of the porphyrin dimers adsorbed on the TiO2 electrode is 2.0 x10(17) molecules per cm(2), that is, the adsorption amount of the porphyrin unit is 4.0 x10(17) cm(-2), which is higher than that of dye sensitizers with pyridyl groups reported so far. The photovoltaic performance of DSSCs based on phenothiazinebridged cyclic porphyrin dimer H-4-Ptz-CPDPy(TEO) is higher than that of DSSCs based on butadiynelinked cyclic porphyrin dimer H-4-C-4-CPDPy(TEO). Moreover, the photovoltaic performances of DSSCs based on cyclic free-base porphyrin dimers are higher than those of DSSCs based on their C-60 inclusion complexes C-60 subset of H-4-C-4-CPDPy(TEO) and C-60 subset of H-4-Ptz-CPDPy(TEO). On the basis of the electrochemical measurements (voltammetry and electrochemical impedance spectroscopy) and the transient absorption spectroscopy, the differences in the photovoltaic performances among these cyclic free-base porphyrin dimers are discussed from kinetic and thermodynamic considerations concerning the electron transfer processes in DSSCs.. |
| 24. |
Yasuo Tanaka, Tomoki Yoneda, Ko Furukawa, Taro Koide, Hirotaka Mori, Takayuki Tanaka, Hiroshi Shinokubo, Atsuhiro Osuka, A Stable Organic -Radical of a Zinc(II)-Copper(I)-Zinc(II) Complex of Decaphyrin, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 10.1002/anie.201505130, 54, 37, 10908-10911, 2015.09, A Zn-II-Cu-I-Zn-II heterotrimetal complex of decaphyrin was synthesized by stepwise metalations: metalation of a [46]decaphyrin with Zn-II ions to produce a 46 decaphyrin bis(Zn-II) complex and its subsequent metalation with Cu-II ion. In the second metalation step, it has been shown that Cu-II ion is reduced to a Cu-I ion in the complex and a dianionic bis(Zn-II) containing [46]decaphyrin ligand is oxidized to the corresponding monoanionic [45]decaphyrin ligand, indicating a non-innocent nature of the decaphyrin ligand. Despite the radical nature, the heterotrimetal complex is fairly stable under ambient conditions and exhibits almost no intermolecular magnetic interaction, owing to extensive delocalization of an unpaired electron in the large -conjugated circuit of decaphyrin moiety.. |
| 25. |
Yasuo Tanaka, Tomoki Yoneda, Ko Furukawa, Taro Koide, Hirotaka Mori, Takayuki Tanaka, Hiroshi Shinokubo, Atsuhiro Osuka, Stable Organic π-Radical of a Zinc(II)–Copper(I)–Zinc(II) Complex of Decaphyrin, Angewandte Chemie International Edition, WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, 10.1002/anie.201505130, 54, 10908-10911, 2015.05. |
| 26. |
Min-Chul Yoon, Pyosang Kim, Hyejin Yoo, Soji Shimizu, Taro Koide, Sumito Tokuji, Shohei Saito, Atsuhiro Osuka, Dongho Kim, Solvent- and Temperature-Dependent Conformational Changes between Huckel Antiaromatic and Mobius Aromatic Species in meso-Trifluoromethyl Substituted [28]Hexaphyrins, JOURNAL OF PHYSICAL CHEMISTRY B, 10.1021/jp207731k, 115, 50, 14928-14937, 2011.12, We investigated the photophysical properties of figure-eight-like meso-hexakis(trifluoromethyl) [26]- and [28]hexaphyrins-(1.1.1.1.1.1) denoted as TFM26H and TFM28H, respectively, using steady-state and time-resolved spectroscopy along with theoretical calculations to explore their electronic and magnetic natures depending on their molecular aromaticity. TFM26H exhibited a well-resolved absorption feature and intense fluorescence, both of which were neither solvent- nor temperature-dependent. These optical properties were in agreement with its Huckel's [4n + 2] aromaticity as observed in typical aromatic porphyrinoids. The S-1-state lifetime of similar to 50 ps for TFM26H in solution was shorter than those in planar aromatic hexaphyrins (>100 ps) presumably due to nonplanar figure-eight geometry of TFM26H. However, TFM28H exhibited remarkable changes in solvent- and temperature-dependent absorption spectra as well as excited-state lifetimes indicating that a dynamic equilibrium occurs between the two conformational species. With the help of quantum mechanical geometry optimization and vertical excitation energy calculations, we found that the figure-eight double-sided conformer observed in the solid-state and single-sided distorted one could be the best candidates for the two conformers, which should be Racket antiaromatic and Mobius aromatic species, respectively, based on their optical characteristics, molecular orbital structures, and excited-state lifetimes. Conformational dynamics between these two conformers of TFM28H was scrutinized in detail by temperature-dependent H-1 NMR spectra in various solvents, which showed that the conformational equilibrium was quite sensitive to solvents and that a conformational change faster than the NMR time-scale occurs even at 173 K.. |
| 27. |
Min-Chul Yoon, Pyosang Kim, Hyejin Yoo, Soji Shimizu, Taro Koide, Sumito Tokuji, Shohei Saito, Atsuhiro Osuka, Dongho Kim, Solvent- and Temperature-Dependent Conformational Changes between Hückel Antiaromatic and Möbius Aromatic Species in meso-Trifluoromethyl Substituted [28]Hexaphyrins, The Journal of Physical Chemistry B, ACS Publications, 10.1021/jp207731k, 115, 14928-14937, 2011.10. |
| 28. |
Yasuo Tanaka, Hirotaka Mori, Taro Koide, Hideki Yorimitsu, Naoki Aratani, Atsuhiro Osuka, Rearrangements of a [36]Octaphyrin Triggered by Nickel(II) Metalation: Metamorphosis to a Directly meso-β-Linked Diporphyrin, Angewandte Chemie International Edition, WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, 10.1002/anie.201105809, 50, 11460-11464, 2011.10. |
| 29. |
Masatoshi Ishida, Jae-Yoon Shin, Jong Min Lim, Byung Sun Lee, Min-Chul Yoon, Taro Koide, Jonathan L. Sessler, Atsuhiro Osuka, Dongho Kim, Neutral Radical and Singlet Biradical Forms of Meso-Free, -Keto, and -Diketo Hexaphyrins(1.1.1.1.1.1): Effects on Aromaticity and Photophysical Properties, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 10.1021/ja204626t, 133, 39, 15533-15544, 2011.10, We have investigated the electronic structures and photophysical properties of 5,10,20,25-tetrakis(pentafluorophenyl)-substituted hexaphyrin(1.1.1.1.1.1) (1) and its meso-keto (2) and meso-diketo derivatives (3) using various spectroscopic measurements. In conjunction with theoretical calculations, these analyses revealed fundamental structure-property relationships within this series, including unusual ground-state electronic structures with neutral, monoradical, and singlet biradical character. The meso-free species 1 is a representative 26 pi-electron aromatic compound and shows characteristic spectroscopic features, including a sharp Soret band, well-defined Q-like bands, and a moderately long excited state lifetime (tau=138 ps). In contrast, the meso-keto derivative 2 displays features characteristic of a neutral monoradical species at the ground state, including the presence of lower energy absorption bands in the NIR spectral region and a relatively short excited-state lifetime (13.9 ps). The meso-diketo 3 exhibits features similar to those of 2, specifically NIR absorptions and a short excited-state lifetime (9.7 ps). Compound 3 is thus assigned as being a ground-state singlet biradicaloid. Two photon absorption (TPA) measurements revealed comparatively large sigma((2)) values of 600 GM for 2 and 1600 GM for 3 with excitation at lambda(ex)=1600 nm as compared to that observed for 1 (sigma((2)): 360 GM). The enhanced nonlinear optical properties of 2 and 3 are rationalized in terms of the open-shell electronic configuration allowing a large, field-induced fluctuation in the electron density (i.e., a large polarization). This interpretation is supported by theoretical evaluations of the static second hyperpolarizabilities (gamma) and gamma density analyses. Furthermore, nucleus-independent chemical shift (NICS) and harmonic oscillator model of aromaticity (HOMA) values and anisotropy of the induced current density (AICD) plots revealed a clear distinction in terms of the aromatic character of 1-3. Importantly, the open-shell radicaloid 2 and singlet biradicaloid 3 can be formally regarded as 27 pi-electron nonaromatic and 26 pi-electron aromatic species, respectively, constrained within a dominant 28 pi-electron conjugated network. On the basis of the combined experimental and theoretical evidence, it is concluded that the meso-carbonyl groups of 2 and 3 play an important role in perturbing the macrocyclic pi-conjugation of the parent hexaphyrin structure 1. In particular, they lead to the imposition of intrinsic radical and biradical character on the molecule as a whole and thus easy-to-discern modifications of the overall electronic effects.. |
| 30. |
Yasuo Tanaka, Hirotaka Mori, Taro Koide, Hideki Yorimitsu, Naoki Aratani, Atsuhiro Osuka, Rearrangements of a [36]Octaphyrin Triggered by Nickel(II) Metalation: Metamorphosis to a Directly meso-beta-Linked Diporphyrin, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 10.1002/anie.201105809, 50, 48, 11460-11464, 2011.10. |
| 31. |
Masatoshi Ishida, Jae-Yoon Shin, Jong Min Lim, Byung Sun Lee, Min-Chul Yoon, Taro Koide, Jonathan L. Sessler, Atsuhiro Osuka, Dongho Kim, Neutral Radical and Singlet Biradical Forms of Meso-Free, -Keto, and -Diketo Hexaphyrins(1.1.1.1.1.1): Effects on Aromaticity and Photophysical Properties, Journal of The American Chemical Society, ACS Publications, 10.1021/ja204626t, 133, 15533-15544, 2011.08. |
| 32. |
Taro Koide, Ko Furukawa, Hiroshi Shinokubo, Jae-Yoon Shin, Kil Suk Kim, Dongho Kim, Atsuhiro Osuka, A Stable Non-Kekulé Singlet Biradicaloid from meso-Free 5,10,20,25-Tetrakis(Pentafluorophenyl)-Substituted [26]Hexaphyrin(1.1.1.1.1.1), Journal of The American Chemical Society, ACS Publications, 10.1021/ja101040s, 132, 7246-7247, 2010.08. |
| 33. |
Taro Koide, Atsuhiro Osuka, Mobius Aromatic Palladium(II) Complexes of a beta-Tetraphenyl meso-Hexakis(pentafluorophenyl) Substituted Hexaphyrin(1.1.1.1.1.1), BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 10.1246/bcsj.20100053, 83, 8, 877-879, 2010.08, Two isomeric Pd-II complexes, 4 and 5, of a beta-tetraphenyl meso-hexakis(pentafluorophenyl) substituted [28]hexaphyrin were isolated, both of which exhibited distinct cliatropic ring currents and electronic absorption spectra characteristic of aromatic porphyrinoids. These complexes have been designated Mobius aromatic species on the basis of their twisted conformations and 28 pi-electronic networks.. |
| 34. |
Taro Koide, Atsuhiro Osuka
, Möbius Aromatic Palladium(II) Complexes of a β-Tetraphenyl meso-Hexakis(pentafluorophenyl) Substituted Hexaphyrin(1.1.1.1.1.1), Bulletin of Chemical Society of Japan, The Chemical Society of Japan, 10.1246/bcsj.20100053, 83, 877-879, 2010.07. |
| 35. |
Taro Koide, Gengo Kashiwazaki, Ko Furukawa, and Atsuhiro Osuka, Homo- and Heterobismetal Complexes of 5-Hydroxy-10,15,25,30-Tetrakis(pentafluorophenyl) Substituted [26]Hexaphyrin(1.1.1.1.1.1), Inorganic Chemistry, American Chemical Society, 10.1021/ic900084p, 48, 4595-4597, 2009.11. |
| 36. |
Taro Koide, Ko Furukawa, Hiroshi Shinokubo, Jae-Yoon Shin, Kil Suk Kim, Dongho Kim, Atsuhiro Osuka, A Stable Non-Kekule Singlet Biradicaloid from meso-Free 5,10,20,25-Tetrakis(Pentafluorophenyl)-Substituted [26]Hexaphyrin(1.1.1.1.1.1), JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 10.1021/ja101040s, 132, 21, 7246-+, 2010.06, A meso,meso-diketohexaphyrin was isolated and characterized as a chemically stable non-Kekule singlet biradicaloid. Two unpaired electrons are seemingly delocalized on two tripyrrolic units separated by C=O bonds. These results underscore the potential of expanded porphyrins to achieve unique electronic states.. |
| 37. |
Taro Koide, Katsuyuki Youfu, Shohei Saito, Atsuhiro Osuka, Multiple conformational changes of β-tetraphenyl meso-hexakis(pentafluorophenyl) substituted [26] and [28]hexaphyrins(1.1.1.1.1.1), Chemical Communications, The Royal Society of Chemistry, 10.1039/B910167E, 6047-6049, 2009.08. |
| 38. |
Taro Koide, Katsuyuki Youfu, Shohei Saito, Atsuhiro Osuka, Multiple conformational changes of beta-tetraphenyl meso-hexakis(pentafluorophenyl) substituted [26] and [28]hexaphyrins(1.1.1.1.1.1), CHEMICAL COMMUNICATIONS, 10.1039/b910167e, 40, 6047-6049, 2009.08, beta-Tetraphenyl meso-hexakis(pentafluorophenyl) substituted [26]hexaphyrin 3 is conformationally flexible between rectangular and figure-of-eight shapes and its two-electron reduced [28] hexaphyrin 4 takes figure-of-eight conformations, which are changed, upon protonation, to twisted conformations with distinct Mobius aromaticity.. |
| 39. |
Taro Koide, Gengo Kashiwazaki, Ko Furukawa, Atsuhiro Osuka, Homo- and Heterobismetal Complexes of 5-Hydroxy-10,15,25,30-tetrakis(pentafluorophenyl)-Substituted [26]Hexaphyrin(1.1.1.1.1.1), INORGANIC CHEMISTRY, 10.1021/ic900084p, 48, 11, 4595-4597, 2009.06, Metalation of meso-free 5,10,20,25-tetrakis(pentafluorophenyl)substituted [26]hexaphyrin(1.1.1.1.1.1) (4) with Cu-II and Zn-II ions afforded homodinuclear complexes 6 and 7, respectively. A demetalation-remetalation protocol provided monozinc(II) complex 9 selectively, from which copper(II)-zinc(II) heterodinuclear complex 10 was prepared effectively.. |
| 40. |
Taro Koide, Gengo Kashiwazaki, Masaaki Suzuki, Ko Furukawa, Min-Chul Yoon, Sung Cho, Dongho Kim, and Atsuhiro Osuka, A Stable Radical from Facile Oxygenation of meso-Free 5,10,20,25-Tetrakis(Pentafluorophenyl) Substituted [26]Hexaphyrin(1.1.1.1.1.1), Angewandte Chemie International Edition, WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, 10.1002/anie.200804570, 47, 9661-9665, 2008.11. |
| 41. |
Taro Koide, Gengo Kashiwazaki, Masaaki Suzuki, Ko Furukawa, Min-Chul Yoon, Sung Cho, Dongho Kim, Atsuhiro Osuka, A Stable Radical Species from Facile Oxygenation of meso-Free 5,10,20,25-Tetrakis(pentafluorophenyl)-Substituted [26]Hexaphyrin(1.1.1.1.1.1), ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 10.1002/anie.200804570, 47, 50, 9661-9665, 2008.11. |
