| 1. |
Keisuke Wada, Yuuya Nagata, Luxia Cui, Toshikazu Ono, Shigehisa Akine, Shunsuke Ohtani, Kenichi Kato, Shixin Fa, Tomoki Ogoshi, Self-Inclusion Complexation of Electron-Accepting Guest into Electron-Donating Cyclic Host by Photoexcitation., Angewandte Chemie (International ed. in English), 10.1002/anie.202404409, e202404409, 2024.04, Self-inclusion complexes consisting of host-guest conjugates are one of the unique supramolecular structures because they form in-state and out-state depending on the external stimuli. Despite many reports of the stimuli-responsive self-inclusion complex formation, study of the structural relaxation from out-state to in-state by photoexcitation has been unexplored. Herein, we report that an electron-donating host and an electron-accepting guest conjugate exhibits the structural relaxation from out-state to in-state by photoexcitation. Formation of the in-state in the excited state resulted in exciplex emission along with the locally excited emission from the out-state. Moreover, this structural relaxation by photoexcitation was suppressed not only by temperature, but also by the presence of guest molecules, resulting in changes in the ratio of the dual emission intensities.. |
| 2. |
Luxia Cui, Ami Horioka, Ryoichi Ishimatsu, Masashi Mamada, Chihaya Adachi, Keishiro Tahara, Yu Hoshino, Toshikazu Ono, Advanced Molecular Design for Efficient Multicolor Electrochemiluminescence and Amplified Spontaneous Emission Based on Tetra‐BF2 Complexes, Advanced Optical Materials, 10.1002/adom.202302803, 2024.01, Abstract
Advanced organoboron dyes, incorporating tetra‐boron difluoride (tetra‐BF2) moieties, are developed, demonstrating efficient electrochemiluminescence (ECL) emissions in the green to orange regions through direct ion annihilation. By introducing diverse alkyl modifications in the molecules, luminescence color tuning is achieved via alterations in conjugation and bending angle. A photoluminescence quantum yield of 100% in dilute solutions is successfully achieved. Notably, the introduction of alkyl groups to the methine side stabilizes the radical ionic state, resulting in a high ECL efficiency of 74% through an efficient radical‐ion annihilation pathway. The key factor is that the energy of the annihilation reaction exceeds the S1 energy required for luminescence. Spin density calculations further elucidate the substituent effects on the radical ions of complexes. Moreover, the lasing properties of these materials in the solution‐processed blend films are investigated, revealing a low amplified spontaneous emission (ASE) threshold (Eth) of 6.40 ± 0.24 µJ cm−2, which is notably lower among organic laser materials. This is attributed to their large Stokes shifts and high quantum yield. The excellent ECL and ASE performances establish these materials as a valuable addition to the existing library of organoboron dyes, offering fresh insights into the development of organic solid‐state lasers.. |
| 3. |
Taro Koide, Toshikazu Ono, Hisashi Shimakoshi, Yoshio Hisaeda, Functions of bioinspired pyrrole cobalt complexes-recently developed catalytic systems of vitamin B-12 related complexes and porphycene complexes, COORDINATION CHEMISTRY REVIEWS, 10.1016/j.ccr.2022.214690, 470, 2022.11, Pyrrole-containing metal complexes widely exist in nature, for example, vitamin B-12, heme, chlorophyll, and their derivatives. Each of them shows significant functions, which are essential for life. To mimic their important functions and substance conversion reactions, numerous pyrrole-containing metal complexes have been synthesized and investigated. This review mainly focuses on cobalt complexes having pyrrolecontaining ligands and the recent progress of molecular transformations catalyzed by the complexes, especially the vitamin B-12-related cobalt complexes and porphycene cobalt complexes. A variety of reaction systems, which enable a number of molecular transformations under mild conditions is described. The construction of new reaction systems and a combination of the materials inspired by natural systems is a promising and effective approach to realizing eco-friendly and cost-effective reaction systems. (C) 2022 Elsevier B.V. All rights reserved.. |
| 4. |
Yoshio Yano, Hidetaka Kasai, Yanyan Zheng, Eiji Nishibori, Yoshio Hisaeda, Toshikazu Ono, Multicomponent Crystals with Competing Intermolecular Interactions: In Situ X-ray Diffraction and Luminescent Features Reveal Multimolecular Assembly of Mechanochemical Conditions., Angewandte Chemie (International ed. in English), 10.1002/anie.202203853, 2022.06, Supramolecular chemistry under mechanochemical conditions has drawn attention because it can induce low-solubility molecules to self-assemble, although most of the reported examples have been limited to two-component systems. We applied mechanochemical synthesis to achieve multimolecular self-assembly in more challenging three-component systems. The produced crystals showed multicolor solid-state luminescence depending on the components when exposed to UV light. Optical outputs and X-ray diffraction studies were used to examine the self-assembling behavior in greater depth. Using synchrotron radiation, in situ X-ray diffraction permitted direct observation of the milling process, which started the self-assembly process within 1 min. This research emphasizes the importance of multicomponent molecules with optical functions and self-assembling behavior and offers the possibility of developing more complicated multicomponent crystals and organic solid solutions for advanced materials.. |
| 5. |
Luxia Cui, Hyuga Shinjo, Takafumi Ichiki, Koichi Deyama, Takunori Harada, Kohei Ishibashi, Takumi Ehara, Kiyoshi Miyata, Ken Onda, Yoshio Hisaeda, Toshikazu Ono, Highly Fluorescent Bipyrrole-Based Tetra-BF2 Flag-Hinge Chromophores: Achieving Multicolor and Circularly Polarized Luminescence., Angewandte Chemie (International ed. in English), 10.1002/anie.202204358, e202204358, 2022.05, This study reports the facile syntheses of tetra-boron difluoride (tetra-BF2 ) complexes, flag-hinge-like molecules that exhibit intense green-to-orange luminescence in solution and yellow-to-red emission in the solid states. Single-crystal structure analysis and density functional theory calculations suggested a bent structure of this series of compounds. The complexes also exhibited excellent optical properties, with quantum yields reaching 100 % and a large Stokes shift. These properties were attributed to the altered bending angle of the molecule in the S1 excited state. As the rotational motion was suppressed around the 2,2'-bipyrrole axis, atropisomers with axial chirality were formed, which are optically resolvable into (R) and (S)-enantiomers through a chiral column. The atropisomers thus function as circularly polarized luminescent (CPL) materials, in which the color (green, green-yellow, and yellow) can be varied by controlling the aggregation state. This rational design of multi-BF2 complexes can potentially realize novel photofunctional materials.. |
| 6. |
Zihan Zhou, Taro Koide, Yoshihito Shiota, Yoshio Yano, Ning Xu, Toshikazu Ono, 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, 26, 03, 263-272, 2022.03, A new meso-tetrakis(3,5-di-tert-butylphenyl) substituted porphycene and its cobalt complex were synthesized and characterized. Several meso-tetraarylporphycene cobalt complexes having different substituents showed catalytic activity for the hydrogen gas evolution reaction (HER) in the presence of trifluoroacetic acid (TFA) under electrochemical reductive conditions. The electrochemical potential of the HER was -1.50V vs. Ag/AgCl in THF. The active species of this reaction were determined to be the ligand reduced species of Co(II) porphycenes. The catalytic efficiencies of the cobalt complexes of meso-aryl substituted porphycenes and meso-tetraphenylporphyrin were compared and meso-tetraphenyl porphycene cobalt complex exhibited the best current efficiency of 72%. Based on these experimental results and theoretical calculations, we proposed a possible HER mechanism of this system.A new porphycene having four 3,5-di-tert-butylphenyl groups at the meso-positions and its cobalt complex were synthesized and characterized. The electrocatalytic hydrogen evolution reaction via the ligand-centered reduction of porphycene cobalt complexes was investigated. The reaction process was revealed by experimental results and theoretical calculations and was clearly different from the system via metal-centered reduction using porphyrin cobalt complex.. |
| 7. |
Yoshio Yano, Toshikazu Ono, Takashi Ohhara, Yoshio Hisaeda, Insights into Proton Dynamics in a Photofunctional Salt-Cocrystal Continuum: Single-Crystal X-ray, Neutron Diffraction, and Hirshfeld Atom Refinement., Chemistry (Weinheim an der Bergstrasse, Germany), 10.1002/chem.202103044, 27, 71, 17802-17807, 2021.12, X-ray diffraction, neutron diffraction, and theoretical calculations were used to investigate the relationship between the optical properties and degree of protonation in acid-base complexes. We prepared five acid-base complexes by using a pyridine-modified pyrrolopyrrole derivative and salicylic acid. Two of the prepared acid-base complexes were polymorphs of guest-free crystals with green emission; the other three were guest-inclusion crystals with yellow emission containing CH2 Cl2 , CH2 Br2 , or C2 H4 Cl2 . The presence or absence of guests caused the emission to change color, altering the hydrogen bond strength between the acid-base complexes. Accurate N⋅⋅⋅H distances between the pyridyl moiety and the carboxy group over the temperature range 123 to 273 K were 1.40 Å for the guest-free crystals and 1.25 Å for the guest-inclusion crystals. Our findings contribute to a better understanding of the complex relationship between photofunction and proton dynamics in acid-base complexes.. |
| 8. |
Haruki Inoue, Yuga Yamashita, Yoshiki Ozawa, Toshikazu Ono, Masaaki Abe, Solid-State Structures and Photoluminescence of Lamellar Architectures of Cu(I) and Ag(I) Paddlewheel Clusters with Hydrogen-Bonded Polar Guests., Molecules (Basel, Switzerland), 10.3390/molecules26216731, 26, 21, 2021.11, Two hexanuclear paddlewheel-like clusters appending six carboxylic-acid pendants have been isolated with the inclusion of polar solvent guests: [Cu6(Hmna)6]·7DMF (1·7DMF) and [Ag6(Hmna)6]·8DMSO (2·8DMSO), where H2mna = 2-mercaptonicotininc acid, DMF = N,N'-dimethylformamide, and DMSO = dimethyl sulfoxide. The solvated clusters, together with their fully desolvated forms 1 and 2, have been characterized by FTIR, UV-Vis diffuse reflectance spectroscopy, TG-DTA analysis, and DFT calculations. Crystal structures of two solvated clusters 1·7DMF and 2·8DMSO have been unambiguously determined by single-crystal X-ray diffraction analysis. Six carboxylic groups appended on the clusters trap solvent guests, DMF or DMSO, through H-bonds. As a result, alternately stacked lamellar architectures comprising of a paddlewheel cluster layer and H-bonded solvent layer are formed. Upon UV illumination (λex = 365 nm), the solvated hexasilver(I) cluster 2·8DMSO gives intense greenish-yellow photoluminescence in the solid state (λPL = 545 nm, ΦPL = 0.17 at 298 K), whereas the solvated hexacopper(I) cluster 1·7DMF displays PL in the near-IR region (λPL = 765 nm, ΦPL = 0.38 at 298 K). Upon complete desolvation, a substantial bleach in the PL intensity (ΦPL |
| 9. |
Mohammad Moniruzzaman, Yoshio Yano, Toshikazu Ono, Yoshio Hisaeda, Hisashi Shimakoshi, Aerobic Electrochemical Transformations of DDT to Oxygen-Incorporated Products Catalyzed by a B-12 Derivative, BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 10.1246/bcsj.20210316, 94, 11, 2784-2791, 2021.11, Electrochemical transformations of DDT into oxygen-incorporated products, amides and esters, catalyzed by a B-12 derivative, heptamethyl cobyrinate perchlorate, have been developed under aerobic conditions. The dechlorinative oxygenation of DDT forms the acyl chloride as an intermediate for the synthesis of the amide and ester in the reaction with the amine and alcohol, respectively. This electrochemical method demonstrated with 20 oxygen-incorporated dechlorinated products up to 88% yields with 15 new compounds and was also successfully applied to the conversion of methoxychlor to an amide and ester.. |
| 10. |
Daiki Koga, Toshikazu Ono, Hyuga Shinjo, Yoshio Hisaeda, Hydrogen Bond Engineering Visualized by Picometer-Level Distortion of Planar Porphyrin Isomers., The journal of physical chemistry letters, 10.1021/acs.jpclett.1c03020, 12, 42, 10429-10436, 2021.10, Directly investigating hydrogen bond (HB) dynamics in molecular materials is a challenging task. Here, we report a set of porphyrin isomers, porphycenes, that visualize slight changes on the order of picometers in the intramolecular HB dynamics. Intramolecular HBs of porphycenes were regulated by the systematic modification at meso positions with methyl (Me), cyclopentyl (Cy5), and cyclohexyl (Cy6) moieties. Notably, the quantum yields varied from 35 to 0.04% in chloroform, depending on a slight distortion in the porphycene framework. SC-XRD, XPS, and NMR clearly revealed that the Me and Cy6 moieties increased the nonradiative deactivation by strengthening the intramolecular NH···N HBs whereas Cy5 retained their photoluminescence properties. This is the first example of how the distortion of planar porphyrinoids at the picometer level along with the strength of the intramolecular NH···N HBs can drastically affect their optical properties. The results revealed new avenues of HB engineering based on porphyrinoids.. |
| 11. |
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.. |
| 12. |
Toshikazu Ono, Kazuki Kimura, Megumi Ihara, Yuri Yamanaka, Miori Sasaki, Hirotoshi Mori, Yoshio Hisaeda, Room-Temperature Phosphorescence Emitters Exhibiting Red to Near-Infrared Emission Derived from Intermolecular Charge-Transfer Triplet States of Naphthalenediimide-Halobenzoate Triad Molecules., Chemistry (Weinheim an der Bergstrasse, Germany), 10.1002/chem.202101685, 27, 37, 9465-9465, 2021.07, Invited for the cover of this issue is Toshikazu Ono, Yoshio Hisaeda and co-workers at Kyushu University and their collaborators at Ochanomizu University, Chuo University, and Institute for Molecular Science. The image depicts a molecular assembly structure shining like a jewel, glowing in the red-to-near infrared region. Read the full text of the article at 10.1002/chem.202100906.. |
| 13. |
Toshikazu Ono, Kazuki Kimura, Megumi Ihara, Yuri Yamanaka, Miori Sasaki, Hirotoshi Mori, Yoshio Hisaeda, Room-temperature Phosphorescence Emitters Exhibiting Red to Near-infrared Emission Derived from Intermolecular Charge-transfer Triplet States of Naphthalenediimide-Halobenzoate Triad Molecules., Chemistry (Weinheim an der Bergstrasse, Germany), 10.1002/chem.202100906, 2021.03, Room-temperature phosphorescence (RTP) emitters have attracted significant attention. However, purely organic RTP emitters in red to near-infrared region have not been properly investigated. In this study, a series of naphthalenediimide- halobenzoate -linked molecules are synthesized, one of which exhibits efficient RTP properties, showing red to near-infrared emission in solid and aqueous dispersion. Spectroscopic studies and single-crystal X-ray diffraction analysis have shown that the difference in the stacking modes of compounds affects the optical properties, and the formation of intermolecular charge-transfer complexes of naphthalenediimide-halobenzoate moiety results in a bathochromic shift of absorption and RTP properties. The time-dependent density functional theory calculations showed that the formation of charge-transfer triplet states and the external heavy atom effect of the halogen atom enhance the intersystem crossing between excited singlet and triplet states.. |
| 14. |
Toshikazu Ono, Kohei Ishihama, Ai Taema, Takunori Harada, Kiyonao Furusho, Masashi Hasegawa, Yuki Nojima, Masaaki Abe, Yoshio Hisaeda, Dinuclear Triple-Stranded Helicates Composed of Tetradentate Ligands with Aluminum(III) Chromophores: Optical Resolution and Multi-color Circularly Polarized Luminescence Properties, Angewandte Chemie - International Edition, 10.1002/anie.202011450, 60, 5, 2614-2618, 2021.02, New chiroptical chromophores, dinuclear triple-stranded helicates, composed of tetradentate ligands with aluminum(III) ions, are described. These are synthesized in two steps using inexpensive pyrrole derivatives, hydrazine, and aluminum chloride. These molecular architectures (ALPHY) show multi-color (cyan, yellow, and orange) photoluminescence in solution and in the solid-state, which depends on the substituents of the ligands. The photoluminescence quantum yields of helicates were up to 54 %. The right-handed (P) and left-handed (M) helicates are so stable that they do not undergo racemization in some solvents and are mirror images according to circular dichroism and circularly polarized luminescence (CPL) with an absolute luminescence dissymmetry factor (g ) of up to the 10 order. Mixing the different helicates produces white-light emission with CPL characters. This study offers a glimpse into the potential applications of chromophores with diverse photophysical properties. lum −3. |
| 15. |
Yoshiki Ozawa, Marino Mori, Hidetoshi Kiyooka, Yuumi Sugata, Toshikazu Ono, Masaaki Abe, Tetra- and Hexanuclear Copper(I) Iminothiolate Complexes: Synthesis, Structures, and Solid-State Thermochromic Dual Emission in Visible and Near-Infrared Regions, Chemical Papars, 2020.11. |
| 16. |
Yoshiki Ozawa, Marino Mori, Hidetoshi Kiyooka, Yuumi Sugata, Toshikazu Ono, Masaaki Abe, Tetra- and hexanuclear copper(I) iminothiolate complexes: synthesis, structures, and solid-state thermochromic dual emission in visible and near-infrared regions, CHEMICAL PAPERS, 10.1007/s11696-020-01251-w, 74, 11, 3717-3725, 2020.11, Two new photoluminescent multinuclear Cu(I) cluster complexes supported by monoanionic bidentate ligandN-methylbenzimidazolethiolate (Me-bimt(-)), [Cu-n(Me-bimt)(n)] withn = 4 (1) and 6 (2), have been synthesized and structurally characterized by single-crystal X-ray diffraction analysis. For1and2, the Cu(I) ions and the Me-bimt(-)ligands construct a cubane-type {Cu4S4} and a hexagonal-prism {Cu6S6} frameworks, respectively. In the crystalline state, complexes1and2exhibit green (lambda(em) = 500 nm) and near-infrared (lambda(em) = 876 nm) emission, respectively, under UV irradiation (lambda(ex) = 365 nm) at room temperature. Both crystals reveal temperature-dependent dual emission below 200 K: complex1emits in the visible wavelength region (lambda(em) = 493 and 542 nm) and complex2in the visible to near-infrared wavelength region (lambda(em) = 752 and 973 nm) which are attributed to multiple photoexcited states at the cluster frameworks with distinct metal nuclearity.. |
| 17. |
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.. |
| 18. |
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.. |
| 19. |
Toshikazu Ono, Hyuga Shinjo, Daiki Koga, Yoshio Hisaeda, Synthesis of a meso-Tetraalkylporphycene Bearing Reactive Sites
Toward Porphycene–Polydimethylsiloxane Hybrids with Enhanced Photophysical Properties, European Journal of Organic Chemistry, 10.1002/ejoc.201901497, 2019, 46, 7578-7583, 2019.12, meso-Tetraalkyl porphycenes exhibit unique optical properties with wide potential applications. The very fact that incorporation of porphycenes into polymeric materials is rare, make this approach a particularly attractive one. In this work, meso-tetrakis(3-butenyl)porphycene bearing four terminal olefin groups is prepared via two synthetic strategies: 1) the McMurry reaction using 5,5′-diacyl-2,2′-bipyrroles as precursors and 2) the oxidative coupling of dipyrroethenes. The newly obtained porphycene has been characterized by single X-ray crystallography. A porphycene–polydimethylsiloxane hybrid film is successfully prepared by a platinum-catalyzed hydrosilylation reaction. The hybrid film can be anchored with tweezers, showing a weak red emission with a quantum yield of 0.4 % at room temperature, whose intensity drastically increases reaching a quantum yield of 6.7 % in liquid nitrogen (77 K). This report represents the first example of porphycene-containing elastomeric films for potential application in various fields.. |
| 20. |
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 the Combination of Experimental and Theoretical Studies, European Journal of Organic Chemistry, 2019.12. |
| 21. |
Ausra Tomkeviciene, Asta Dabulienė, Tomas Matulaitis, Matas Guzauskas, Viktorija Andruleviciene, Juozas Vidas Grazulevicius, Yuri Yamanaka, Yoshio Yano, Toshikazu Ono, Bipolar thianthrene derivatives exhibiting room temperature phosphorescence for oxygen sensing, Dyes and Pigments, 10.1016/j.dyepig.2019.107605, 170, 2019.11, The series of donor-acceptor (D-A) compounds consisting of a thianthrene donor and either a benzophenone or a diphenylsulfone acceptor units were designed and synthesized via Suzuki cross-coupling. By varying the number of donor units, as well as by introducing heavy atom (Br) into the molecular structure the impact of these substituents on the thermal, electrochemical and emissive properties of the compounds was studied. The compound containing two thianthrene units appeared to have higher thermal stability and higher glass transition temperature than monosubstituted derivative. All thianthrenyl substituted benzophenone or diphenylsulfone compounds showed bipolar behavior. Strong room temperature phosphorescence and dual fluorescence-phosphorescence were observed at room temperature. The compounds containing stronger electron acceptor diphenylsulfone demonstrated a two-fold higher photoluminescence quantum yield values up to 19% in rigid Zeonex® films than that benzophenone derivatives. The crystals of some synthesized compounds demonstrated oxygen sensing ability.. |
| 22. |
Bipolar thianthrene derivatives exhibiting room temperature phosphorescence for oxygen sensing. |
| 23. |
Ning Xu, Toshikazu Ono, Yoshio Hisaeda, Symmetry Reduction of Porphycenes with Finely Tuned Optical and Electronic Properties through Oxidative Cyclization of E/Z-Mixed Dipyrroethenes, Chemistry - A European Journal, 10.1002/chem.201902080, 25, 50, 11680-11687, 2019.09, The main obstacle to the widespread application of porphycenes lies in the lack of efficient and economical methods for their production. Discovery of new synthetic methodologies for porphycene derivatives are important for fine-tuning of their optical and electrochemical properties. Herein, the preparation of a set of AABB-, ABAB-, and ABBA-type meso-tetrasubstituted unsymmetric porphycenes is reported. Their synthesis involved the acid-catalyzed oxidative coupling of AA- and BB-dipyrroethenes, or AB-type dipyrroethenes, as precursors in yields of up to 19 %. The structures were unambiguously confirmed by X-ray crystallography. The type and position of substituents in the unsymmetric porphycenes enabled fine-tuning of the optical and electronic properties, which are discussed in terms of their UV/Vis absorption, fluorescence spectroscopies, cyclic voltammetry, and density functional theory calculations.. |
| 24. |
Toshikazu Ono, Yoshifumi Tsukiyama, Sou Hatanaka, Yuma Sakatsume, Tomoki Ogoshi, Yoshio Hisaeda, Inclusion crystals as vapochromic chemosensors: fabrication of a mini-sensor array for discrimination of small aromatic molecules based on side-chain engineering of naphthalenediimide derivatives, JOURNAL OF MATERIALS CHEMISTRY C, 10.1039/c9tc03140e, 7, 31, 9726-9734, 2019.08, Vapochromism, chromism induced by vapor desorption/absorption, has received considerable attention in recent years due to its potential applications in chemical sensors for toxic gases and vapors. In this paper, a set of naphthalene diimide (NDI) derivatives with various bulky groups is investigated for chromogenic and fluorogenic detection of small aromatic molecules in the vapor phase. Among the studied compounds, NDI with a 2-benzophenone unit in its structure exhibited a unique vapochromic/vapoluminescent behavior toward toluene, p-xylene, 4-fluorotoluene, and anisole. Detection limits in the parts-per-million (ppm) range are accomplished with some compounds. Optical measurements and X-ray crystal structure analyses clearly suggested that intermolecular charge-transfer interactions between the electron-deficient NDI and the electron-rich aromatic guest molecules as well as the inherent porosity of the sensor materials contribute to their unique sensing abilities. Discrimination of xylene isomers was demonstrated by taking advantage of selective inclusion phenomena. Two binary sensor ensembles, including our previously reported NDI derivative, enable the construction of a mini-sensor array that can be used to discriminate benzene derivatives-including xylene isomers-with the naked eye. The present simple, low-cost, metal-free, and effective sensor materials may promote practical applications with advantages relative to other known sensor materials.. |
| 25. |
Salt-cocrystal continuum for photofunction modulation: stimuli-responsive fluorescence color-tuning of pyridine-modified intramolecular charge-transfer dyes and acid complexes. |
| 26. |
Symmetry Reduction of Porphycenes with Finely Tuned Optical and Electronic Properties through Oxidative Cyclization of E/Z-Mixed Dipyrroethenes. |
| 27. |
Highly malleable haem-binding site of the haemoprotein HasA permits stable accommodation of bulky tetraphenylporphycenes. |
| 28. |
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, 2019.04. |
| 29. |
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, 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.. |
| 30. |
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, 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.. |
| 31. |
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. |
| 32. |
Visible Light-Driven, One-pot Amide Synthesis Catalyzed by the B-12 Model Complex under Aerobic Conditions. |
| 33. |
Front Cover: Visible Light‐Driven, One‐pot Amide Synthesis Catalyzed by the B 12 Model Complex under Aerobic Conditions (ChemPlusChem 3/2019). |
| 34. |
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, 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.. |
| 35. |
Erika Sakakibara, Yuma Shisaka, Hiroki Onoda, Daiki Koga, Ning Xu, Toshikazu Ono, Yoshio Hisaeda, Hiroshi Sugimoto, Yoshitsugu Shiro, Yoshihito Watanabe, Osami Shoji, Highly malleable haem-binding site of the haemoprotein HasA permits stable accommodation of bulky tetraphenylporphycenes, RSC Advances, 10.1039/c9ra02872b, 9, 32, 18697-18702, 2019.01, Iron(iii)- and cobalt(iii)-9,10,19,20-tetraphenylporphycenes, which possess bulky phenyl groups at the four meso positions of porphycene, were successfully incorporated into the haem acquisition protein HasA secreted by Pseudomonas aeruginosa. Crystal structure analysis revealed that loops surrounding the haem-binding site are highly flexible, remodelling themselves to accommodate bulky metal complexes with significantly different structures from the native haem cofactor.. |
| 36. |
Toshikazu Ono, Yoshifumi Tsukiyama, Sou Hatanaka, Yuma Sakatsume, Tomoki Ogoshi, Yoshio Hisaeda, Inclusion crystals as vapochromic chemosensors
Fabrication of a mini-sensor array for discrimination of small aromatic molecules based on side-chain engineering of naphthalenediimide derivatives, Journal of Materials Chemistry C, 10.1039/c9tc03140e, 7, 31, 9726-9734, 2019.01, Vapochromism, chromism induced by vapor desorption/absorption, has received considerable attention in recent years due to its potential applications in chemical sensors for toxic gases and vapors. In this paper, a set of naphthalene diimide (NDI) derivatives with various bulky groups is investigated for chromogenic and fluorogenic detection of small aromatic molecules in the vapor phase. Among the studied compounds, NDI with a 2-benzophenone unit in its structure exhibited a unique vapochromic/vapoluminescent behavior toward toluene, p-xylene, 4-fluorotoluene, and anisole. Detection limits in the parts-per-million (ppm) range are accomplished with some compounds. Optical measurements and X-ray crystal structure analyses clearly suggested that intermolecular charge-transfer interactions between the electron-deficient NDI and the electron-rich aromatic guest molecules as well as the inherent porosity of the sensor materials contribute to their unique sensing abilities. Discrimination of xylene isomers was demonstrated by taking advantage of selective inclusion phenomena. Two binary sensor ensembles, including our previously reported NDI derivative, enable the construction of a mini-sensor array that can be used to discriminate benzene derivatives - including xylene isomers - with the naked eye. The present simple, low-cost, metal-free, and effective sensor materials may promote practical applications with advantages relative to other known sensor materials.. |
| 37. |
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, 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.. |
| 38. |
Yoshio Yano, Toshikazu Ono, Sou Hatanaka, Daniel T. Gryko, Yoshio Hisaeda, Salt-cocrystal continuum for photofunction modulation
Stimuli-responsive fluorescence color-tuning of pyridine-modified intramolecular charge-transfer dyes and acid complexes, Journal of Materials Chemistry C, 10.1039/c9tc02524c, 7, 29, 8847-8854, 2019.01, The regulation of proton transfer dynamics between acid-base complexes is of significant interest in the pharmaceutical industry and materials chemistry. However, the extent of proton transfer in the solid state is difficult to predict, and identifying the salts (protonation), cocrystals (hydrogen bond), and salt-cocrystal continuum (partially protonated states) remain challenging topics. Here we report that the three states (salts/cocrystals/salt-cocrystal continuum) can be distinguished by photoluminescent color changes based on acid-base complexes consisting of a pyridine-modified pyrrolopyrrole dye and organic acids. Structure-property relationships of 10 complexes indicated that ΔpKa value (pKa (protonated base)-pKa (acid)) and the crystalline environment determine the extent of proton transfer, which governs the intramolecular charge-transfer (ICT) strength of the complexes and tunes the photoluminescence properties. Enhancement of the ICT strength leads to a bathochromic shift of emission from blue to green to yellow under UV light. The salt-cocrystal continuum (0 a 2Cl2, owing to the extent of proton transfer from the acid to the pyridine moiety of the dye being modulated by inclusion and desorption of CH2Cl2. This study suggests that the rational design of photoluminescent acid-base complexes is useful for obtaining novel photofunctional materials.. |
| 39. |
Switching of Monomer Fluorescence, Charge-Transfer Fluorescence, and Room-Temperature Phosphorescence Induced by Aromatic Guest Inclusion in a Supramolecular Host. |
| 40. |
Learning from B-12 enzymes: biomimetic and bioinspired catalysts for eco-friendly organic synthesis. |
| 41. |
Synthesis of Trifluoromethylated B-12 Derivative and Photolysis of Cobalt(III)-Trifluoromethyl Bond. |
| 42. |
Piezofluorochromism in Charge-Transfer Inclusion Crystals: The Influence of High Pressure versus Mechanical Grinding. |
| 43. |
Tomoki Ogoshi, Hiromu Tsuchida, Takahiro Kakuta, Tada-Aki Yamagishi, Ai Taema, Toshikazu Ono, Manabu Sugimoto, Motohiro Mizuno, Ultralong Room-Temperature Phosphorescence from Amorphous Polymer Poly(Styrene Sulfonic Acid) in Air in the Dry Solid State, Advanced Functional Materials, 10.1002/adfm.201707369, 28, 16, 2018.04, Polymer-based room-temperature-phosphorescent (RTP) materials are attractive alternatives to low-molecular-weight organic RTP compounds because they can form self-standing transparent films with high thermal stability. However, their RTP lifetimes in air are usually short (<
≈0.4 s). Here, the simple organic amorphous polymer, poly(styrene sulfonic acid) (PSS), exhibits an ultralong RTP lifetime in air when desiccated. The maximum lifetime is 1.22 s, which is three times that of previously reported RTP amorphous organic polymers. The lifetime can be controlled by the PSS molecular weight and by the ratio of sulfonic acid groups introduced into the polymer. The dry polymers should enable unprecedented molecular engineering in organic molecule-based optoelectronic devices because of the self-standing and thermal stability attributes.. |
| 44. |
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, 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.. |
| 45. |
Md. Jakir Hossain, Toshikazu Ono, Kosuke Wakiya, Yoshio Hisaeda, A vitamin B-12 derivative catalyzed electrochemical trifluoromethylation and perfluoroalkylation of arenes and heteroarenes in organic media, CHEMICAL COMMUNICATIONS, 10.1039/c7cc06221d, 53, 79, 10878-10881, 2017.10, The electrochemical trifluoromethylation and perfluoroalkylation of aromatic compounds mediated by a vitamin B-12 derivative as a cobalt-based catalyst has been developed. The Co(I) species of a vitamin B-12 derivative, prepared by controlled-potential electrolysis at -0.8 V vs. Ag/AgCl in methanol, reacted with RfI (R-f = CF3, n-C3F7, n-C4F9, n-C8F17, and n-C10F21) to form a Co-R-f complex. This complex released an R-f 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 B-12 catalyzed trifluoromethylation and perfluoroalkylation of aromatic compounds as a cobalt-mediated catalyst.. |
| 46. |
Shogo Amemori, Kazuya Iseda, Shizuka Anan, Toshikazu Ono, Kenta Kokado, Kazuki Sada, Thermoresponsivity of polymer solution derived from a self-attractive urea unit and a self-repulsive lipophilic ion unit, POLYMER CHEMISTRY, 10.1039/c7py00591a, 8, 26, 3921-3925, 2017.07, The preparation of the polymers having a self-attractive urea unit via hydrogen bonding and a selfrepulsive lipophilic ion unit via electrostatic interaction was carried out to achieve the thermoresponsivity of polymer solution. The solubility of the obtained copolymers depended on the balance between the attractive force induced by hydrogen bonding among the urea units and the repulsive force attributed to the dissociation of the ionic units. In aprotic and nonpolar solvents, the solubility of the polymers was changed from insoluble to soluble with the increasing content of the ionic units. Moreover, in acetonitrile and 1,2-dichloroethane, the UCST-type thermoresponsivity was observed. This result indicated that the UCST-type thermoresponsivity was induced by cleavage of the hydrogen bonds among urea units upon heating, and at the cloud point, the repulsive force among the ionic units overwhelmed the attractive force. From the result of this research, we would like to emphasize that the combination of a lipophilic ion pair and other self-attractive units can be a simple principle for the molecular design of UCST-type thermoresponsive polymers in any media.. |
| 47. |
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, 2017.06, 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.. |
| 48. |
Toshikazu Ono, Daiki Koga, Yoshio Hisaeda, Facile Synthesis of 9,10,19,20-Tetraalkylporphycenes, CHEMISTRY LETTERS, 10.1246/cl.161019, 46, 2, 260-262, 2017.02, meso-Tetraalkylporphycenes were synthesized in a few steps using intramolecular oxidative coupling of the Z-isomer of 5,6dialkyldipyrroethenes. The use of a hypervalent iodine(III) reagent, namely phenyliodine(III) bis(trifluoroacetate), is essential for performing these reactions.. |
| 49. |
Sou Hatanaka, Toshikazu Ono, Yoshiio Hisaeda, Turn-On Fluorogenic and Chromogenic Detection of Small Aromatic Hydrocarbon Vapors by a Porous Supramolecular Host, CHEMISTRY-A EUROPEAN JOURNAL, 10.1002/chem.201601812, 22, 30, 10346-10350, 2016.07, Benzene, toluene, ethylbenzene, the isomers of xylene, and trimethylbenzene are harmful volatile organic compounds and pose risks to human health and the environment. However, there are currently no effective chemosensors for vapors of these compounds. A porous supramolecular host for turn-on fluorogenic and chromogenic detection of the vapors of small aromatic hydrocarbons is presented. The host was constructed from a naphthalenediimide derivative that was supramolecularly connected to tris(pentafluorophenyl)borane. The amorphous powder form of the host allowed for effective accommodation of vapors of small aromatic hydrocarbons, resulting in a guest-dependent fluorescence emission. Increases in the fluorescence yield of 76-, 46-, and 37-fold were observed with toluene, benzene, and m-xylene, respectively. Negligible responses were obtained with common organic solvents. This simple supramolecular host could be applied as a useful sensor of small aromatic hydrocarbon vapors.. |
| 50. |
Toshikazu Ono, Yasushi Hisaoka, Akira Onoda, Koji Oohora, Takashi Hayashi, Oxygen-binding Protein Fiber and Microgel: Supramolecular Myoglobin-Poly(acrylate) Conjugates, CHEMISTRY-AN ASIAN JOURNAL, 10.1002/asia.201501415, 11, 7, 1036-1042, 2016.04, A supramolecular conjugate of myoglobin (Mb) and water-soluble poly(acrylate), (PA(5k) and PA(25k), where 5k and 25k represent the molecular weight of the polymers, respectively), is constructed on the basis of a noncovalent heme-heme pocket interaction. The modified heme with an amino group linked to the terminus of one of the heme-propionates is coupled to the side-chain carboxyl groups of poly(acrylate) activated by N-hydroxysuccinimide. The ratios of the heme-modified monomer unit and the unmodified monomer unit (m:n) in the polymer chains of Heme-PA(5k) and Heme-PA(25k) were determined to be 4.5:95.5 and 3.1:96.9, respectively. Subsequent addition of apoMb to the conjugated polymers provides Mb-connected fibrous nanostructures confirmed by atomic force microscopy. A mixture of the heme-modified polymer and dimeric apomyoglobin as a cross-linker forms a microgel in which the reconstituted myoglobin retains its native exogenous ligand binding activity.. |
| 51. |
Masahiko Ohta, Toshikazu Ono, Kenta Kokado, Akira Kakugo, Kazuki Sada, Lipophilic Ionomers with Bulky Ion-Pairs and Effect of Counterion on Miscibility of the Ionomer Blends, MACROMOLECULAR CHEMISTRY AND PHYSICS, 10.1002/macp.201500281, 217, 3, 433-444, 2016.02, In this study, polystyrene (PS) ionomers having tetraalkylammonium with a series of counterions are prepared with various feed ratio of the ionic units and blended with nonionic poly(n-butyl methacrylate) (PBMA) which is originally immiscible with PS. According to differential scanning calorimetry analysis, in the blends of ionomers with tetraarylborate and PBMA, the ionomers with more than 1 mol% of the ionic units are completely miscible with PBMA. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction measurements reveal that the bulky and lipophilic ion-pair inhibits the association of ions and instead induces the attractive interaction to alkyl groups of PBMA. Tensile tests of the miscible specimen exhibit both characteristic behavior, that is, high tensile strength as PS and high elongation property of PBMA.. |
| 52. |
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, 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 pi-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.. |
| 53. |
Sarah K. Edwards, Toshikazu Ono, Shenliang Wang, Wei Jiang, Raphael M. Franzini, Jong Wha Jung, Ke Min Chan, Eric T. Kool, In Vitro Fluorogenic Real-Time Assay of the Repair of Oxidative DNA Damage, CHEMBIOCHEM, 10.1002/cbic.201500184, 16, 11, 1637-1646, 2015.07, The repair of oxidative damage to DNA is essential to avoid mutations that lead to cancer. Oxidized DNA bases, such as 8-oxoguanine, are a main source of these mutations, and the enzyme 8-oxoguanine glycosylase 1 (OGG1) is the chief human enzyme that excises 8-oxoguanine from DNA. The activity of OGG1 has been linked to human inflammation responses and to cancer, and researchers are beginning to search for inhibitors of the enzyme. However, measuring the activity of the enzyme typically requires laborious gel-based measurements of radiolabeled DNAs. Here we report the design and properties of fluorogenic probes that directly report on the activity of OGG1 (and its bacterial homologue Fpg) in real time as the oxidized base is excised. The probes are short, modified DNA oligomers containing fluorescent DNA bases and are designed to utilize 8-oxoguanine itself as a fluorescence quencher. Screening of combinations of fluorophores and 8-oxoguanine revealed two fluorophores, pyrene and tCo, that are strongly quenched by the damaged base. We tested 42 potential probes containing these fluorophores: the optimum probe, OGR1, yields a 60-fold light-up signal in vitro with OGG1 and Fpg. It can report on oxidative repair activity in mammalian cell lysate and with bacterial cells overexpressing a repair enzyme. Such probes might prove useful in quantifying enzyme activity and performing competitive inhibition assays.. |
| 54. |
Toru Okawara, Akane Doi, Toshikazu Ono, Masaaki Abe, Kenji Takehara, Yoshio Hisaeda, Shigenori Matsushima, Synthesis and X-ray crystallography of bipyrroles: impacts of a CO-pi interaction on their structure, TETRAHEDRON LETTERS, 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 C=O center dot center dot center dot pi interaction in the solid-state and showed the longest emission wavelength because of increase in structural flexibility. (C) 2015 Elsevier Ltd. All rights reserved.. |
| 55. |
Akira Onoda, Yuta Tanaka, Toshikazu Ono, Shotaro Takeuchi, Akira Sakai, Takashi Hayashi, Myoglobin-based non-precious metal carbon catalysts for an oxygen reduction reaction, JOURNAL OF PORPHYRINS AND PHTHALOCYANINES, 10.1142/S108842461550039X, 19, 1-3, 510-516, 2015.01, A non-precious metal catalyst (NPMC) promoting a four-electron oxygen reduction reaction (ORR) was synthesized by heat treatment of myoglobin (Mb) containing a heme (iron protoporphyrin IX) as a source of iron, nitrogen, and carbon atoms. Samples of the mixture of Mb and carbon black (Vulcan XC72R: VC) were pyrolyzed at 740, 840, 940, 1040 or 1140 degrees C under N-2 flow. The microstructures of the carbonized Mb catalysts were characterized by XRD, Raman spectroscopy, XPS, and TEM. Results indicate that the iron-containing active site is embedded within the surface structure in an amorphous domain of the carbon materials. The catalyst ink in a 0.05 wt% Nafion solution in isopropanol was coated onto a glassy carbon electrode and the ORR activity of Mb-based NPMCs was evaluated in a rotating disk electrode experiment in an O-2-saturated 0.1 M HClO4 solution at 25 degrees C. The catalyst synthesized at 940 degrees C has the highest ORR activity in terms of the onset potential and the current density. In contrast, pyrolytic temperatures above 940 degrees C decrease the activity, suggesting that the active structure of the catalyst apparently decomposes at higher temperatures. The Koutecky-Levich plots indicate that the Mb-based catalyst prepared at 940 degrees C catalyzes four-electron ORR (n = ca. 4). The catalysts prepared at other temperatures have n values of 3.6 at 740 degrees C, 3.7 at 840 degrees C, and 2.9 at 1040 degrees C. The ORR of Mb/VC is diffusion-controlled at potentials lower than 0.3 V (vs. RHE) and the onset potential is 0.84 +/- 0.01 V.. |
| 56. |
Toshikazu Ono, Sarah K. Edwards, Shenliang Wang, Wei Jiang, Eric T. Kool, Monitoring eukaryotic and bacterial UDG repair activity with DNA-multifluorophore sensors, NUCLEIC ACIDS RESEARCH, 10.1093/nar/gkt309, 41, 12, 2013.07, We report the development of simple fluorogenic probes that report on the activity of both bacterial and mammalian uracil-DNA glycosylase (UDG) enzymes. The probes are built from short, modified single-stranded oligonucleotides containing natural and unnatural bases. The combination of multiple fluorescent pyrene and/or quinacridone nucleobases yields fluorescence at 480 and 540 nm (excitation 340 nm), with large Stokes shifts of 140-200 nm, considerably greater than previous probes. They are strongly quenched by uracil bases incorporated into the sequence, and they yield light-up signals of up to 40-fold, or ratiometric signals with ratio changes of 82-fold, on enzymatic removal of these quenching uracils. We find that the probes are efficient reporters of bacterial UDG, human UNG2, and human SMUG1 enzymes in vitro, yielding complete signals in minutes. Further experiments establish that a probe can be used to image UDG activity by laser confocal microscopy in bacterial cells and in a human cell line, and that signals from a probe signalling UDG activity in human cells can be quantified by flow cytometry. Such probes may prove generally useful both in basic studies of these enzymes and in biomedical applications as well.. |
| 57. |
Toshikazu Ono, Masahiko Ohta, Kazuki Sada, Ionic Polymers Act as Polyelectrolytes in Nonpolar Media, ACS MACRO LETTERS, 10.1021/mz3002879, 1, 11, 1270-1273, 2012.11, Polyelectrolytes are ubiquitous materials, and their unique properties originate from dissociation of ionic groups to the small number of macromolecular ions and the large number of small counterions. They have been exploited only in water or high-dielectric media and scarcely in nonpolar ones (epsilon |
| 58. |
Masahiko Ohta, Toshikazu Ono, Kazuki Sada, Layer-by-layer Deposition of Ionomers with Lipophilic Ion-pairs Dissociated in Less-polar Media, CHEMISTRY LETTERS, 10.1246/cl.2011.648, 40, 6, 648-650, 2011.06, Two kinds of oppositely charged polystyrene ionomers bearing the bulky and lipophilic phosphazenium cation or diborateimidazolide anion that are soluble and dissociated partially into ions even in nonpolar solvents were prepared. Alternate complexes of them were fabricated in less-polar solvent, acetone, layer-by-layer onto a gold substrate and silica nanoparticles.. |
| 59. |
Toshikazu Ono, Takahiro Sugimoto, Seiji Shinkai, Kazuki Sada, Molecular Design of Superabsorbent Polymers for Organic Solvents by Crosslinked Lipophilic Polyelectrolytes, ADVANCED FUNCTIONAL MATERIALS, 10.1002/adfm.200801221, 18, 24, 3936-3940, 2008.12, Molecular design of lipophilic polyelectrolyte gels as superabsorbent polymers that exhibit a high degree of swelling in less-polar and nonpolar organic solvents is demonstrated. A small amount of tetraalkylammonium tetraphenylborate with long alkyl chains as a lipopholic ion pair is incorporated into crosslinked polyacrylates with variable alkyl chain lengths to provide novel lipophilic polyelectrolyte gels. Their swelling degree becomes more than 100 times as much as their dried weights in various organic solvents. The high effectiveness of the swellable solvents shifts to the polar ones by decreasing the length of the alkyl chain. Swelling or collapsing of the lipophilic polyelectrolyte gels originates from both incompatibility of the polymer chains in the media and dissociation of ionic groups. Thus, a unique superabsorbency is observed when the polymer chains have good compatibility with the solvents and the solvents have relatively high polarities enough to dissociate the ionic groups. By varying the polarity of the neutral monomer in these polyelectrolyte gels, the design of gels that can absorb solvents of nearly any polarity is demonstrated.. |
| 60. |
Toshikazu Ono, Takahiro Sugimoto, Seiji Shinkai, Kazuki Sada, Lipophilic polyelectrolyte gels as super-absorbent polymers for nonpolar organic solvents, NATURE MATERIALS, 10.1038/nmat1904, 6, 6, 429-433, 2007.06, Polyelectrolyte gels that are known as super- absorbent polymers swell and absorb water up to several hundred times their dried weights and have become ubiquitous and indispensable materials in many applications(1,2). Their superior swelling abilities originate from the electrostatic repulsion between the charges on the polymer chains and the osmotic imbalance between the interior and exterior of the gels(3). However, no superabsorbent polymers for volatile organic compounds ( VOCs), and especially for nonpolar organic solvents (epsilon |
