Updated on 2024/09/20

写真a

 
CHANG Hochol
 
Organization
Faculty of Science and Engineering Professor
Other responsible organization
Applied Chemistry Course of Graduate School of Science and Engineering, Master's Program
Applied Chemistry Course of Graduate School of Science and Engineering, Doctoral Program
Contact information
The inquiry by e-mail is 《here
Profile
2008-2013: Associate Professor, Hokkaido University, Japan (with Prof. M. KATO) Apr.-Sep. 2008: Visiting Researcher, University of Bath, UK (with Prof. F. MARKEN) 2002-2006: PRESTO Researcher, JST 2001-2008: Assistant Professor, Kyoto University, Japan (with Prof. S. KITAGAWA) 2001: Ph. D. Kyoto University, Japan (Prof. Susumu KITAGAWA) 1998: M. S. Tokyo Metropolitan University, Japan (Prof. Susumu KITAGAWA) 1995: B. S. Korea University, Japan
External link

Degree

  • 博士(工学) ( 京都大学 )

  • 修士(理学) ( 東京都立大学 )

Education

  • 2001.3
     

    Kyoto University   Graduate School, Division of Engineering   doctor course   completed

  • 1998.3
     

    Tokyo Metropolitan University   Graduate School, Division of Natural Science   master course   completed

  • 1995.3
     

    朝鮮大学校   理学部   化学科   graduated

  • 1991.3
     

    東京朝鮮中高級学校   graduated

Research History

  • 2013.4 -  

    中央大学理工学部 教授

  • 2008.11 - 2013.3

    北海道大学大学院理学研究院 准教授

  • 2008.12 -  

    北海道大学大学院理学研究院元素戦略教育研究センター 連携研究員

  • 2007.4 - 2008.10

    京都大学大学院工学研究科 助教

  • 2008.4 - 2008.9

    英国バース大学 客員研究員

  • 2007.6 -  

    理化学研究所播磨研究所放射光科学総合研究センター量子秩序研究グループ空間秩序研究チーム 客員研究員

  • 2001.4 - 2007.3

    京都大学大学院工学研究科 助手

  • 2002.11 - 2006.3

    科学技術振興機構戦略的創造研究推進事業さきがけ研究「秩序と物性」領域 研究員

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Professional Memberships

  • 分子科学会

  • 日本化学会

  • 錯体化学会

  • 日本液晶学会

Research Interests

  • 機能性分子材料、液晶、触媒

  • 液晶、錯体、触媒

Research Areas

  • Nanotechnology/Materials / Functional solid state chemistry  / 機能物性化学

  • Nanotechnology/Materials / Inorganic/coordination chemistry  / 無機化学

Papers

  • Experimental verification of double-four-ring-type aluminosilicate molecule as a single-source precursor for zeolite synthesis

    Akira Imaizumi, Yurika Ohnishi, Akinobu Nakada, Akinori Honda, Takeshi Matsumoto, Kenji Katayama, Ho-Chol Chang

    Bulletin of the Chemical Society of Japan   97 ( 6 )   2024.6

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    Publishing type:Research paper (scientific journal)   Publisher:Oxford University Press (OUP)  

    Abstract

    While a variety of functional zeolites have been synthesized using hydrothermal methods with conventional discrete Al and Si sources, control of the composition, structure, and function of the targeted zeolites often involves expensive and time-consuming trial-and-error approaches. Despite ongoing efforts to manipulate zeolite formation by adjusting Al and Si sources and reaction conditions, limited attention has been given to studies on zeolite synthesis using molecular precursors (MPs) with preorganized Al–O–Si bonds. Here, we demonstrate the synthesis of LTA-type zeolites using [TMA]4[Al4Si4O12(OH)8]·13H2O ([MP]; TMA = tetramethylammonium cation) with a double-four-ring (D4R)-type core structure, which is known to be a secondary building unit in the LTA-type zeolite, as a MP. Here, we demonstrate the successful synthesis of LTA-type zeolites using [MP] under hydrothermal conditions at 100 to 200 °C in the presence of 1 equiv. of NaOH or NaCl. Notably, when discrete Al and Si sources were used instead of [MP] under otherwise identical conditions (the same Si/Al ratio, Na+ content, and temperature), GIS-, SOD-, and FAU-type zeolites lacking the D4R structure were obtained in addition to the LTA-type zeolites.

    DOI: 10.1093/bulcsj/uoae060

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    Other Link: https://academic.oup.com/bcsj/article-pdf/97/6/uoae060/58356424/uoae060.pdf

  • Switching of the redox centers of a tris-2-mercaptophenolato chromium(<scp>iii</scp>) metalloligand by a guest metal ion

    Masanori Wakizaka, Takeshi Matsumoto, Ho-Chol Chang

    Dalton Transactions   52 ( 6 )   1538 - 1542   2023

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    Publishing type:Research paper (scientific journal)   Publisher:Royal Society of Chemistry (RSC)  

    This work demonstrated the S-site binding tri-nuclear structure using a tris-type 2-mercaptophenolato metalloligand and switching of the redox centers.

    DOI: 10.1039/d2dt03502b

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  • Redox-active ligands for chemical, electrochemical, and photochemical molecular conversions Reviewed

    Akinobu Nakada, Takeshi Matsumoto, Ho-Chol Chang

    Coordination Chemistry Reviews   473   214804 - 214804   2022.12

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Elsevier {BV}  

    DOI: 10.1016/j.ccr.2022.214804

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  • Synthesis of Microporous Aluminosilicate by Direct Thermal Activation of Phenyl-Substituted Single-Source Aluminosilicate Molecular Precursors. International journal

    Akira Imaizumi, Akinobu Nakada, Takeshi Matsumoto, Toshiyuki Yokoi, Ho-Chol Chang

    Inorganic chemistry   61 ( 34 )   13481 - 13496   2022.8

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    Language:English   Publishing type:Research paper (scientific journal)  

    The construction of aluminosilicates from versatile molecular precursors (MPs) represents a promising alternative strategy to conventional processes based on monomeric molecular or polymeric Al and Si sources. However, the use of MPs often suffers from drawbacks such as the decomposition of the core structures in the presence of solvents, acids, or bases. In this work, we demonstrate a simple thermal synthesis of porous aluminosilicates from single-source spiro-7-type MPs that consist of a tetrahedral Al atom and six Si atoms functionalized with 12 phenyl (Ph) groups, (C+)[Al{Ph2Si(OSiPh2O)2}2]- (C+[AlSi6]-; C+ = pyridinium cation (PyH+), Na+, K+, Rb+, or Cs+), without using a solvent or activator. Microporous aluminosilicates synthesized via the thermal treatment of C+[AlSi6]- under a 79% N2 + 21% O2 atmosphere exhibited extremely low carbon contents (0.10-1.28%), together with Si/Al ratios of 3.9-6.7 ± 0.2 and surface areas of 103.1-246.3 m2/g. The solid-state 27Al and 29Si MAS NMR spectra suggest that the obtained aluminosilicates with alkali cations retain a tetrahedral Al site derived from the spiro-7-type core structure. After a proton-exchange reaction, the aluminosilicates showed almost 1.5 times higher reactivity in the catalytic ring-opening of styrene oxide than the aluminosilicate before proton exchange due to the catalytically active OH site being predominantly bridged by tetrahedral Al and Si atoms. These results suggest that the present MP strategy is a promising method for the introduction of key structures into active inorganic materials.

    DOI: 10.1021/acs.inorgchem.2c02006

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  • Light-induced electron transfer/phase migration of a redox mediator for photocatalytic C–C coupling in a biphasic solution

    Ren Itagaki, Shin-ya Takizawa, Ho-Chol Chang, Akinobu Nakada

    Dalton Transactions   51 ( 24 )   9467 - 9476   2022

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    Publishing type:Research paper (scientific journal)   Publisher:Royal Society of Chemistry (RSC)  

    Light-induced electron transfer and phase migration of ferrocene/ferrocenium suppress the backward charge recombination enabling efficient photocatalysis in a biphasic solution.

    DOI: 10.1039/d2dt01334g

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  • Tunable Synchronicity of Molecular Valence Tautomerism with Macroscopic Solid-Liquid Transition by Molecular Lattice Engineering

    Mayumi Chida, Satoru Takahashi, Ryunosuke Konishi, Takeshi Matsumoto, Akinobu Nakada, Masanori Wakizaka, Wataru Kosaka, Hitoshi Miyasaka, Ho-Chol Chang

    CHEMISTRY-A EUROPEAN JOURNAL   27 ( 66 )   16354 - 16366   2021.11

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:WILEY-V C H VERLAG GMBH  

    The combination of a cobalt-dioxolene core that exhibits valence tautomerism (VT) with pyridine-3,5-dicarboxylic acid functionalized with chains bearing two, four, or six oxyethylene units led to new complexes ConEGEspy (n = 2, 4, and 6). These complexes commonly form violet crystals of the low-spin (ls)-[Co-III(nEGEspy)(2)(3,6-DTBSQ)(3,6-DTBCat)] (ls-[Co-III], 3,6-DTBSQ = 3,6-di-tert-butyl semiquinonato, 3,6-DTBCat = 3,6-di-tert-butyl catecholato). Interestingly, violet crystals of Co2EGEspy in the ls-[Co-III] transitioned into a green liquid, accompanied by an almost complete VT shift (94 %) to the high-spin (hs)-[Co-II(nEGEspy)(2)(3,6-DTBSQ)(2)] (hs-[Co-II]) upon melting. In contrast, violet crystals of Co4EGEspy and Co6EGEspy in the ls-[Co-III] exhibited partial VT (33 %) and only a 9.3 % VT shift after melting, respectively. These data demonstrate the tunability of the synchronicity of the molecular VT and macroscopic solid-liquid transitions by optimizing the tethered chains, thus establishing a new strategy for coupling bistable molecules with the macroscopic world.

    DOI: 10.1002/chem.202103090

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  • Functional Group-Directed Photochemical Reactions of Aromatic Alcohols, Amines, and Thiols Triggered by Excited-State Hydrogen Detachment: Additive-free Oligomerization, Disulfidation, and C(sp2)-H Carboxylation with CO2. International journal

    Kanae Abe, Akinobu Nakada, Takeshi Matsumoto, Daiki Uchijyo, Hirotoshi Mori, Ho-Chol Chang

    The Journal of organic chemistry   86 ( 1 )   959 - 969   2021.1

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    Exploring new types of photochemical reactions is of great interest in the field of synthetic chemistry. Although excited-state hydrogen detachment (ESHD) represents a promising prospective template for additive-free photochemical reactions, applications of ESHD in a synthetic context remains scarce. Herein, we demonstrate the expansion of this photochemical reaction toward oligomerization, disulfidation, and regioselective C(sp2)-H carboxylation of aromatic alcohols, thiols, and amines. In the absence of any radical initiators in tetrahydrofuran upon irradiation with UV light (λ = 280 or 300 nm) under an atmosphere of N2 or CO2, thiols and catechol afforded disulfides and oligomers, respectively, as main products. Especially, the photochemical disulfidation proceeded highly selectively with the NMR and quantum yields of up to 69 and 0.46%, respectively. In stark contrast, the photolysis of phenylenediamines and aminophenols results in photocarboxylation in the presence of CO2 (1 atm). p-Aminophenol was quantitatively carboxylated by photolysis for 17 h with a quantum yield of 0.45%. Furthermore, the photocarboxylation of phenylenediamines and aminophenols proceeds in a highly selective fashion on the aromatic C(sp2)-H bond next to a functional group, which is directed by the site-selective ESHD of the functional groups for the formation of aminyl and hydroxyl radicals.

    DOI: 10.1021/acs.joc.0c02456

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  • Excited-state hydrogen detachment from a tris-(o-phenylenediamine) iron(ii) complex in THF at room temperature. International journal

    Akinobu Nakada, Takuji Koike, Takeshi Matsumoto, Ho-Chol Chang

    Chemical communications (Cambridge, England)   56 ( 98 )   15414 - 15417   2020.12

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    Language:English   Publishing type:Research paper (scientific journal)  

    We previously reported that a tris-(o-phenylenediamine) iron(ii) complex promotes photochemical H2 generation and C-H carboxylation of o-phenylenediamine without any additives under N2 and CO2 atmospheres, respectively, in tetrahydrofuran at room temperature. Herein, the key mechanistic process, namely, excited-state hydrogen detachment from the o-phenylendiamine moiety, is demonstrated under an N2 atmosphere.

    DOI: 10.1039/d0cc06219g

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  • Facile and selective synthesis of zeolites L and W from a single-source heptanuclear aluminosilicate precursor

    Akira Imaizumi, Akinobu Nakada, Takeshi Matsumoto, Ho-Chol Chang

    CRYSTENGCOMM   22 ( 35 )   5862 - 5870   2020.9

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ROYAL SOC CHEMISTRY  

    Zeolites are usually synthesized by hydrothermal reactions using monomeric or polymeric Al- and Si-containing precursors, whereas simple and direct routes for the rational synthesis of zeolites remain elusive. In this work, we demonstrate the synthesis of the two zeolites L (LTL type) and W (MER type) from a single molecular precursor (MP), (PyH)[Al{Ph2Si(OSiPh2O)(2)}(2)] (AlSi6 ; PyH = pyridinium cation), under hydrothermal conditions using KOH as the only additive. Under acidic conditions, the heptanuclear structure of AlSi6 is hydrolyzed without cleavage of the Si-Ph bonds, while the hydrothermal reaction under basic conditions allows the crystallization of zeolites under concomitant Si-Ph cleavage. X-ray diffraction and scanning electron microscopy studies revealed that zeolite L, which exhibits a cylindrical morphology, was produced selectively by hydrothermal treatment of AlSi6 at 160-200 degrees C in the presence of KOH (3 eq.). In contrast, increasing the amount of KOH (from 6 to 12 eq.) resulted in the formation of zeolite W with a twin-ball morphology. The specific surface area and Si/Al ratios of the synthesized zeolites L and W are comparable to those previously reported. These experimental results suggest promising potential of structurally and compositionally well-defined MPs, including even those with organic functional groups, for the construction of zeolites.

    DOI: 10.1039/d0ce00546k

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  • Molecular Insights into the Ligand-Based Six-Proton- and Six-Electron-Transfer Processes Between Tris-ortho-Phenylenediamines and Tris-ortho-Benzoquinodiimines

    Takeshi Matsumoto, Risa Yamamoto, Masanori Wakizaka, Akinobu Nakada, Ho-Chol Chang

    Chemistry - A European Journal   26 ( 43 )   9609 - 9619   2020.8

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Wiley-VCH Verlag  

    The global demand for energy and the concerns over climate issues renders the development of alternative renewable energy sources such as hydrogen (H2) important. A high-spin (hs) FeII complex with o-phenylenediamine (opda) ligands, [FeII(opda)3]2+ (hs-[6R]2+), was reported showing photochemical H2 evolution. In addition, a low-spin (ls) [FeII(bqdi)3]2+ (bqdi: o-benzoquinodiimine) (ls-[0R]2+) formation by O2 oxidation of hs-[6R]2+, accompanied by ligand-based six-proton and six-electron transfer, revealed the potential of the complex with redox-active ligands as a novel multiple-proton and -electron storage material, albeit that the mechanism has not yet been understood. This paper reports that the oxidized ls-[0R][PF6]2 can be reduced by hydrazine giving ls-[FeII(opda)(bqdi)2][PF6]2 (ls-[2R][PF6]2) and ls-[FeII(opda)2(bqdi)][PF6]2 (ls-[4R][PF6]2) with localized ligand-based proton-coupled mixed-valence (LPMV) states. The first isolation and characterization of the key intermediates with LPMV states offer unprecedented molecular insights into the design of photoresponsive molecule-based hydrogen-storage materials.

    DOI: 10.1002/chem.202001873

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  • Impact of Group 10 Metals on the Solvent-Induced Disproportionation of o-Semiquinonato Complexes Reviewed

    Yamada, Shota, Matsumoto, Takeshi, Chang, Ho-Chol

    Chemistry – A European Journal   25 ( 35 )   8268 - 8278   2019

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    Publishing type:Research paper (scientific journal)   Publisher:Wiley  

    DOI: 10.1002/chem.201900172

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  • Direct Photochemical C–H Carboxylation of Aromatic Diamines with CO2 under Electron-Donor- and Base-free Conditions Reviewed

    Takeshi Matsumoto, Daiki Uchijyo, Takuji Koike, Ryoya Namiki, Ho-Chol Chang

    Sci. Rep.   8 ( 1 )   14623   2018.10

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    DOI: 10.1038/s41598-018-33060-3

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    Other Link: http://www.nature.com/articles/s41598-018-33060-3

  • Tuning the Electron Acceptability of the [Mo6S8] Cluster Core by Decorating It with Methyl Groups on the Face-Bridging µ3-Sulfides

    Takeshi Matsumoto, Ryoya Namiki, Ho-Chol Chang

    European Journal of Inorganic Chemistry   2018 ( 35 )   3900 - 3904   2018.9

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    Methylation of the molybdenum sulfide cluster unit [Mo6S8(PEt3)6] (1) with CH3OTf resulted in the formation of mono- and dimethylated cluster units, [Mo6S8–x(SCH3)x(PEt3)6]OTf·yCH2Cl2 {[2]OTf·0.5CH2Cl2 (x = 1, y = 0.5) and [3]OTf·CH2Cl2 (x = 2, y = 1)}. Structural and electrochemical investigations revealed that the methylation of the µ3-S ligand(s) induced a characteristic structural distortion of the [Mo6S8] cluster core and enhanced its ability to accept multiple electrons.

    DOI: 10.1002/ejic.201800587

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  • Tuning the Mesomorphism and Redox Response of Anionic-Ligand-Based Mixed-Valent Nickel(II) Complexes by Alkyl-Substituted Quaternary Ammonium Cations Reviewed

    Nakamura, Yuichi, Matsumoto, Takeshi, Sakazume, Yasutaka, Murata, Junnosuke, Chang, Ho-Chol

    Chemistry-a European Journal   24 ( 29 )   7398 - 7409   2018

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    Publishing type:Research paper (scientific journal)   Publisher:Wiley  

    DOI: 10.1002/chem.201706006

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  • Coordination Behavior of N, N'-Bis(diisopropylphosphinoacetyl)-o-phenylenediamide with Ni-II and Cu-I Ions Reviewed

    Takahiro Ito, Takeshi Matsumoto, Masanori Wakizaka, Ho-Chol Chang

    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY   ( 29 )   3498 - 3507   2017.8

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:WILEY-V C H VERLAG GMBH  

    The reaction of N,N'-bis(diisopropylphosphoniumacetyl)-o-phenylenediamide dibromide (H4L center dot 2Br) with Ni-II[ClO4]center dot 6H(2)O in the presence of Et3N resulted in the formation of N, N'-bis(diisopropylphosphinoacetyl)-o-phenylenediamidate nickel(II) ([Ni-II(L)]). The single-crystal X-ray diffraction analysis of [Ni-II(L)] revealed that each pair of N and P atoms in L2- coordinates in a tetradentate fashion to afford a distorted square-planar Ni-II amide complex. On the other hand, N, N'-bis(diisopropylphosphinoacetyl)- o-phenylenediamide copper(I) bromide ([Cu-I(H2L)Br]) was isolated by the reaction of H4L center dot 2Br with [Cu-I(MeCN)(4)][PF6] in the presence of Et3N. The structural analysis revealed that the two P atoms in H2L coordinate in a bidentate fashion to afford a trigonal-planar Cu-I complex, in which the amide moieties remain in free form. Complex [Ni-II(L)] showed reversible deprotonation processes on the amidate ligand (L2-), whereas the protonated state of the N atoms of the amide ligand (H2L) in [Cu-I(H2L)Br] was maintained, even in the presence of excess Et3N, suggesting substantial stability for the protonated state.

    DOI: 10.1002/ejic.201700433

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  • A Coordination Network with Ligand-Centered Redox Activity Based on facial-[Cr-III(2-mercaptophenolato)(3)](3-) Metalloligands Reviewed

    Masanori Wakizaka, Takeshi Matsumoto, Atsushi Kobayashi, Masako Kato, Ho-Chol Chang

    CHEMISTRY-A EUROPEAN JOURNAL   23 ( 41 )   9919 - 9925   2017.7

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:WILEY-V C H VERLAG GMBH  

    The design of redox-active metal-organic frameworks and coordination networks (CNs), which exhibit metaland/or ligand-centered redox activity, has recently received increased attention. In this study, the redox-active metalloligand (RML) [Me4N](3)fac-[CrIII(mp)(3)] (1) (mp= 2-mercaptophenolato) was synthesized and characterized by single-crystal X-ray diffraction analysis, and its reversible ligand-centered one-electron oxidation was examined by cyclic voltammetry and spectroelectrochemical measurements. Since complex 1 contains O/S coordination sites in three directions, complexation with K+ ions led to the formation of the two-dimensional honeycomb sheet-structured [K(3)fac{ Cr-III(mp)(3)}(H2O)(6)] n (2.6H(2)O), which is the first example of a redox-active CN constructed from a RML with o-disubstituted benzene ligands. Herein, we unambiguously demonstrate the ligand-centered redox activity of the RML within the CN 2.6H(2)O in the solid state.

    DOI: 10.1002/chem.201701613

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    Other Link: http://orcid.org/0000-0002-6932-9758

  • Structural and Spectroscopic Studies on the Interactions of ortho-Phenylenediamine and Li+, Na+, Mg2+, or Ca2+ Ions Reviewed

    Takeshi Matsumoto, Junki Ishii, Masanori Wakizaka, Ho-Chol Chang

    CHEMISTRY LETTERS   46 ( 2 )   232 - 235   2017.2

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:CHEMICAL SOC JAPAN  

    The coordinative interactions of o-phenylenediamine and alkali or alkaline earth metals like Li+, Na+, Mg2+, or Ca2+, were investigated by X-ray structural analyses and IR, UV-vis, and (HNMR)-H-1 spectroscopies. These studies revealed that the coordinative interactions of o-phenylenediamine with metal ions through amino groups depend on the ratio of the charge and the ionic radius of the metal ions both in the solid state and in THF solution.

    DOI: 10.1246/cl.160997

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  • Dehydrogenation of anhydrous methanol at room temperature by o-aminophenol-based photocatalysts Reviewed

    Masanori Wakizaka, Takeshi Matsumoto, Ryota Tanaka, Ho-Chol Chang

    NATURE COMMUNICATIONS   7   2016.7

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:NATURE PUBLISHING GROUP  

    Dehydrogenation of anhydrous methanol is of great importance, given its ubiquity as an intermediate for the production of a large number of industrial chemicals. Since dehydrogenation of methanol is an endothermic reaction, heterogeneous or homogeneous precious-metal-based catalysts and high temperatures are usually required for this reaction to proceed. Here we report the photochemical dehydrogenation of anhydrous methanol at room temperature catalysed by o-aminophenol (apH(2)), o-aminophenolate (apH(-)) and the non-precious metal complex trans-[Fe-II(apH)(2)(MeOH)(2)]. Under excitation at 289 +/- 10 nm and in the absence of additional photosensitizers, these photocatalysts generate hydrogen and formaldehyde from anhydrous methanol with external quantum yields of 2.9 +/- 0.15%, 3.7 +/- 0.19% and 4.8 +/- 0.24%, respectively, which are the highest values reported so far to the best of our knowledge. Mechanistic investigations reveal that the photo-induced formation of hydrogen radicals triggers the reaction.

    DOI: 10.1038/ncomms12333

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  • Shape-memory Platinum(II) Complexes: Intelligent Vapor-History Sensor with ON-OFF Switching Function Reviewed

    Y. Shigeta, A. Kobayashi, T. Ohba, M. Yoshida, T. Matsumoto, H.-C. Chang, M. Kato

    Chem. Eur. J.   22 ( 8 )   2682 - 2690   2016

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Wiley-Blackwell  

    DOI: 10.1002/chem.201503247

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  • Highly polar solvent-induced disproportionation of a cationic Pt(II)-diimine complex containing an o-semiquinonato Reviewed

    Shota Yamada, Takeshi Matsumoto, Masanori Wakizaka, Ho-Chol Chang

    DALTON TRANSACTIONS   45 ( 12 )   4974 - 4977   2016

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ROYAL SOC CHEMISTRY  

    Chemical one-electron oxidation of [Pt-II(3,5-DTBCat)(DTBbpy)] (1) (3,5-DTBCat = 3,5-di-tert-butyl catecholato, DTBbpy = 4,4'-di-tert-butyl-2,2'-bipyridine) afforded the corresponding paramagnetic complex, [Pt-II(3,5-DTBSQ)(DTBbpy)]+PF6- (1(PF6)), as a result of ligand-centred oxidation. While complex 1 is relatively stable in common organic solvents, the present study demonstrates that cationic [1](+) is subject to an unprecedented solvent-induced disproportionation in highly polar solvents such as DMSO and DMF, which results in the formation of 1 and a free benzoquinone.

    DOI: 10.1039/c6dt00487c

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  • Syntheses and Structures of Molybdenum-oxo Complexes Prepared by the Reactions of [MoII2(OAc)4] with tert-Butyl- or Bromo-substituted Catechols Reviewed

    T. Matsumoto, H.Yano, M. Wakizaka, A. Kobayashi, M. Kato, H.-C. Chang

    Bull. Chem. Soc. Jpn.   88 ( 1 )   74 - 83   2015

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:The Chemical Society of Japan  

    DOI: 10.1246/bcsj.20140208

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  • PB26 Electrochemical Transformation of Metallomesogens Possessing Catecholato or Benzenedithiolato

    SAKAZUME Yasutaka, WAKIZAKA Masanori, MATSUMOTO Takeshi, CHANG Ho-Chol

    Proceedings of Japanese Liquid Crystal Society Annual meeting   2015   _PB26 - 1_-_PB26-2   2015

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    Language:Japanese   Publisher:Japanese Liquid Crystal Society  

    Redox-active liquid crystals that have both liquid crystalline and redox properties are expected to give new and attractive electronic devises controlled by electrochemical methods at ambient conditions. We have reported the design and properties of Pt(II) metallomegens possessing redox-active catecholato or benzenedithiolato and long alkyl chain-substituted bipyridine ligands. Especially, metallomesogen possessing 3,5-t-butylcatecholato shows direct electrochemical redox responses and electrochemically -induced transformation between columnar liquid crystal and isotropic ionic liquid phases. In this work, the effects of coordinating atoms, the position of substituents, temperature, and electrolytes on electrochemical property of metallomesogens will be presented.

    DOI: 10.11538/ekitou.2015.0__PB26

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  • Vapochromic Luminescence and Flexibility Control of Porous Coordination Polymers by Substitution of Luminescent Multinuclear Cu(I)-cluster Nodes Reviewed

    T. Hayashi, A. Kobayashi, H. Ohara, M. Yoshida, T. Matsumoto, H.-C. Chang, M. Kato

    Inorg. Chem.   54 ( 18 )   8905 - 8913   2015

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Chemical Society (ACS)  

    DOI: 10.1021/acs.inorgchem.5b00578

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  • Interactions Between the Trianionic Ligand-centred Redox-active Metalloligand [CrIII(perfluorocatecholato)3]3– and Guest Metal Ions Reviewed

    M. Wakizaka, T. Matsumoto, A. Kobayashi, M. Kato, H.-C. Chang

    Dalton Trans.   44 ( 32 )   14304 - 14314   2015

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    <p>The redox behavior of redox-active metalloligand (RML), [CrIII(F4Cat)3]3− (F4Cat: perfluorocatecholato), responsible for interaction with guest metal ions in solution are systematically demonstrated.</p>

    DOI: 10.1039/c5dt01963j

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  • Systematic Syntheses and Metalloligand-Doping of Flexible Porous Coordination Polymers Composed of a Co(III)-metalloligand Reviewed

    A. Kobayashi, Y. Suzuki, T. Ohba, T. Ogawa, T. Matsumoto, S. Noro, H.-C. Chang, M. Kato

    Inorg. Chem.   54 ( 6 )   2522 - 2535   2015

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    DOI: 10.1021/ic5021302

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  • Immobilization of a Redox-active Catecholato Pt(II) Complex on an Indium-doped Tin Oxide Electrode via Phosphonate Anchors Reviewed

    Hirotaka Honda, Takeshi Matsumoto, Ryo Tamura, Katsuhiko Kanaizuka, Atsushi Kobayashi, Masako Kato, Masa-aki Haga, Ho-Chol Chang

    CHEMISTRY LETTERS   43 ( 8 )   1189 - 1191   2014.8

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    The reaction of tetraethyl [2,3-dihydroxy-1,4-phenylenebis-(methylene)]bisphosphonate (Et4LH2) with [PtCl2(DTBbPY)] (DTBbpy: 4,4'-di-tert-butyl-2,2'-bipyridine) afforded [Pt(Me4L)-(DTBbpY)] (1), [Pt(Bn4L-)(DTBbPY)] (2), Na-2[Pt(Me2L)-(DTBbpy)] (3), and [Pt(H4L)(DTBbpy)] (4) with tetramethyl-, tetrabenzyl-, half-protected, and fully-deprotected groups under different reaction conditions. The introduction of phosphonatomethyl groups at the 3,6-position of a redox-active catecholato unit led to slight shifts in charge-transfer bands and catecholato-centered redox processes in solution. The presence of deprotonated anchors in 3 resulted in the immobilization of the complex onto an indium-doped tin oxide electrode, demonstrating a well-defined redox response from the tethered complex.

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  • Synthesis and Vapor-adsorption Behavior of a Flexible Porous Coordination Polymer Built from a Bis(bipyridyl)-Cu(I) Metalloligand Reviewed

    Atsushi Kobayashi, Akira Sugiyama, Tadashi Ohba, Yui Suzuki, Ho-Chol Chang, Masako Kato

    CHEMISTRY LETTERS   43 ( 7 )   1070 - 1072   2014.7

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    A new porous coordination polymer (PCP), formulated as {[La-2(III)(mu(3)-OH)(CH3COO)(2)(H2O)][Cu-I(dmdcbpy)(2)]center dot 9H(2)O} (La2Cu center dot 9H(2)O; H(2)dmdcbpy: 6,6'-dimethyl-5,5'-dicarboxy-2,2'bipyridine), was synthesized and characterized by X-ray diffraction and vapor-adsorption isotherms. The porous framework of La2Cu consists of a 3-D coordination network of the Cu(I)-metalloligand and the tetranuclear La-4 cluster {La-4(mu(3)-OH)(2)(CH3COO)(4)(H2O)(2)}. La2Cu exhibits reversible guest adsorption desorption for various vapors, with reversible structural transformations.

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  • Spontaneous Construction of Nanoneedles Using Ruthenium Complex-conjugated Porphyrins on Substrates Reviewed

    T. Togashi, A. Izumi, H. Kon, K. Kanaizuka, M .Ishizaki, R. Miyake, H.C. Chang, M. Haga, M. Sakamoto, M. Kurihara

    Chem. Lett.   43   1201 - 1203   2014.5

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  • Photo-induced dimerization reaction coupled with oxygenation of a platinum(II)-hydrazone complex Reviewed

    A. Kobayashi, D. Yamamoto, H. Horike, K. Sawaguchi, T. Matsumoto, K. Nakajima, H.-C. Chang, M. Kato

    Inorg. Chem.   ( 53 )   2014.2

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  • Flexible Coordination Polymers Composed of Luminescent Ru(II)-Metalloligands: Importance of Position of Coordination Site in Metalloligands Reviewed

    A. Kobayashi, T. Ohba, E. Saitoh, Y. Suzuki, S.-i. Noro, H.-C. Chang, M. Kato

    Inorg. Chem.   ( 53 )   2014.2

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  • Hysteretic vapour response of a heterodinuclear platinum(II)-copper(II) complex derived from the dimer-of-dimer motif and the guest-absorbing site Reviewed

    Tadashi Ohba, Atsushi Kobayashi, Ho-Chol Chang, Takahiko Kouyama, Tatsuhisa Kato, Masako Kato

    DALTON TRANSACTIONS   43 ( 20 )   7514 - 7521   2014

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    A heterodinuclear complex, syn-[PtCu(mu-pyt)(2)(bpy)(2)](2+) (syn-[PtCu]; Hpyt = pyridine-2-thiol, bpy = 2,2 '-bipyridine), was synthesized by stepwise complexation. Three different crystal structures of the hexafluorophosphate salts with solvent molecules as guests at the axial sites of the Cu(II) ions, i.e. syn-[PtCu-G] (G = acetonitrile, acetone, and methanol), were determined by X-ray analyses. In the solid-state, these complexes adopt dimer-of-dimer motifs characteristic of the syn isomers of dinuclear complexes with two pyt bridging ligands arranged in a head-to-head configuration. These dinuclear complexes have a short Pt. Cu distance (2.75-2.81 angstrom) and slightly different intermolecular Pt...Pt distances (3.43-3.51 angstrom), which affect the colour of the solid complexes. All the syn-[PtCu-G] systems absorbed/desorbed vapour molecules; however, they exhibit different chromic changes because of the unique structural hysteresis of the desorbed form, i. e. syn-[PtCu], according to powder X-ray diffraction measurements. In addition, guest exchange occurred in the syn-[PtM-G] complexes upon exposure to the vapour of different solvents.

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  • Photo- and Vapor-Controlled Luminescence of Rhombic Dicopper(I) Complexes Containing Dimethyl Sulfoxide Reviewed

    Atsushi Kobayashi, Kahori Komatsu, Hiroki Ohara, Waka Kamada, Yuko Chishina, Kiyoshi Tsuge, Ho-Chol Chang, Masako Kato

    INORGANIC CHEMISTRY   52 ( 22 )   13188 - 13198   2013.11

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    Halide-bridged rhombic dicopper(I) complexes, [Cu-2(mu-X)(2)(DMSO)(2)(PPh3)(2)] (X = I-, Br-; DMSO = dimethyl sulfoxide; PPh3 = triphenylphosphine), were synthesized, the iodide complex of which exhibited interesting photochromic luminescence driven by photoirradiation and by exposure to DMSO vapor in the solid state. Single-crystal Xray diffraction measurements revealed that the iodo and bromo complexes (abbreviated Cu2I2-[O,O] and Cu2Br2-[O,O]) were isomorphous, and that the two DMSO ligands were coordinated to the Cu(I) ion via the O atom in both complexes. Both complexes exhibited bright blue phosphorescence at room temperature (lambda(em) = 435 nm, Phi(em) = 0.19 and 0.14 for Cu2I2[O,O] and Cu2Br2-[O,O], respectively) with a relatively long emission lifetime (tau(em) similar to 200 mu s at 77 K) derived from the mixed halide-to-ligand and metal-to-ligand charge transfer ((XLCT)-X-3 and (MLCT)-M-3) excited state. Under UV irradiation, the blue phosphorescence of Cu2Br2-[O,O] disappeared uneventfully and no new emission band appeared, whereas the blue phosphorescence of Cu2I2-[O,O] rapidly disappeared with simultaneous appearance of a new green emission band (lambda(em) = 500 nm). On further irradiation, the green emission of the iodide complex gradually changed to bright yellowish-green (lambda(em) = 540 nm); however, this change could be completely suppressed by lowering the temperature to 263 K or in the presence of saturated DMSO vapor. The initial blue phosphorescence of Cu2I2-[O,O] was recovered by exposure to DMSO vapor at 90 degrees C for a few hours. IR spectroscopy and theoretical calculations suggest that the DMSO ligand underwent linkage isomerization from O-coordination to S-coordination, and both the occurrence of linkage isomerization and the removal of DMSO result in contraction of the rhombic Cu2O4-O-2 core to make the Cu.-Cu interaction more effective. In the contracted core, the triplet cluster-centered ((CC)-C-3) emissive state is easily generated by thermal excitation of the (XLCT)-X-3 and (MLCT)-M-3 mixed transition state, resulting in the green to yellowish-green emission. In contrast, the Cu"Cu distance in Cu2Br2-[O,O] is considerably longer than that of Cu2I2[O,O], which destabilizes the (CC)-C-3 emissive state, resulting in the nonemissive character.

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  • Self-association and Columnar Liquid Crystalline Phase of Cationic Alkyl-substituted-Bipyridine Benzenedithiolato Gold(III) Complexes Reviewed

    T. Ogawa, M. Sakamoto, H. Honda, T. Matsumoto, A. Kobayashi, M. Kato, H.-C. Chang

    Dalton. Trans.   ( 42 )   2013.7

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  • Nonprecious-metal-assisted photochemical hydrogen production from ortho-phenylenediamine Reviewed

    Takeshi Matsumoto, Ho-Chol Chang, Masanori Wakizaka, Sho Ueno, Atsushi Kobayashi, Akira Nakayama, Tetsuya Taketsugu, Masako Kato

    Journal of the American Chemical Society   135 ( 23 )   8646 - 8654   2013.6

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    The combination of o-phenylenediamine (opda), which possesses two proton- and electron-pooling capability, with Fe(II) leads to the photochemical hydrogen-evolution reaction (HER) in THF at room temperature without addition of photosensitizers. From the THF solution, the tris(o-phenylenediamine) iron(II) complex, [FeII(opda)3](ClO4)2 (1), was isolated as a photoactive species, while the deprotonated oxidized species was characterized by X-ray crystallographic analysis, electrospray ionization mass spectrometry, and UV-vis NIR spectra. Furthermore, the HER is photocatalyzed by hydroquinone, which serves as a H+/e- donor. The present work demonstrates that the use of a metal-bound aromatic amine as a H+/e- pooler opens an alternative strategy for designing nonprecious-metal-based molecular photochemical H2 production/storage materials. © 2013 American Chemical Society.

    DOI: 10.1021/ja4025116

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  • Integration of Alkyl-Substituted Bipyridyl Benzenedithiolato Platinum(II) Complexes with Cadmium(II) Ion via Selective Dative Bond Formation Reviewed

    Hirotaka Honda, Takeshi Matsumoto, Misaki Sakamoto, Atsushi Kobayashi, Ho-Chol Chang, Masako Kato

    INORGANIC CHEMISTRY   52 ( 8 )   4324 - 4334   2013.4

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    The presence of lone pairs on the Pt and S atoms of [Pt(Bdt)(DTBbpy)] (1) (Bdt = 1,2-benzenedithiolato and DTBbpy = 4,4'-di-tert-butyl-2,2'-bipyridine) and [Pt (Bdt) (C13bpy)] (2) (C13bpy = 4,4'-ditridecyl-2,2'-bipyridine) led to selective dative bond formation with Cd(II). Complexes 1 and 2 show no binding interaction with Zn(II), while they bind selectively with Cd(II) to give a twisted trinuclear complex, [Cd{Pt(Bdt)(DTBbpy)}(2)(ClO4)(H2O)](ClO4) (3), and a shuttlecock-shaped tetranuclear complex, [Cd{Pt(Bdt)(C13bpy)}(3)(H2O)](ClO4)(2)center dot CH2Cl2 (4), respectively, depending upon the alkyl groups substituted on the 2,2'-bipyridine. The two platinum moieties in 3 are connected to the seven-coordinated Cd atom through Pt -&gt; Cd (2.7331(7) and 2.7936(7) angstrom) and S -&gt; Cd (2.690(3), 2.940(3), and 3.067(3) angstrom) dative bonds, while the three moieties in 4 are connected to the tetrahedral Cd atom only by S -&gt; Cd (2.552(4) angstrom) dative bonds. These structural variations found in 3 and 4 are caused not only by steric hindrance of the t-Bu groups but also by the microsegregation effect derived from the tridecyl chains. The three platinum moieties in 4 align so as to form a parallel orientation of their dipole moments, in contrast to the twisted arrangement found in 3. The dative bonds formed in 3 and 4 are commonly stable in the solid state and in less coordinative solvents such as dichloromethane, while dissociation behavior of platinum moieties with Cd(II) was observed in more coordinative THF. UV-vis and NMR spectroscopy unsealed the characteristic association/dissociation properties depending on the coordination abilities of solvents. Finally, the present study revealed that the formation of dative bonds between the platinum moieties with Cd(II) plays important roles not only in stabilizing the ground states, which leads to blue shifts in both absorption and emission energies, but also in electronic interactions between the moieties, which are revealed by electrochemical studies.

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    Other Link: http://orcid.org/0000-0002-6932-9758

  • Selective Dative Bond Formation of Bipyridyl Benzenedithiolato Platinum(II) Complexes with Cadmium(II) Ion Reviewed

    Hirotaka Honda, Takeshi Matsumoto, Misaki Sakatomo, Atsushi Kobayashi, Ho-Chol Chang, Masako Kato

    Inorganic Chemistry   ( 52 )   4324 - 4334   2013.3

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  • Vapour and mechanically induced chromic behaviour of platinum complexes with a dimer-of-dimer motif and the effects of hetero metal ions Reviewed

    Tadashi Ohba, Aatsushi Kobayashi, Ho-Chol Chang, Masako Kato

    Dalton Transactions   ( 42 )   5490 - 5499   2013.2

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  • Vapour and mechanically induced chromic behaviour of platinum complexes with a dimer-of-dimer motif and the effects of heterometal ions Reviewed

    Tadashi Ohba, Atsushi Kobayashi, Ho-Chol Chang, Masako Kato

    DALTON TRANSACTIONS   42 ( 15 )   5514 - 5523   2013

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    Heterodinuclear complexes, syn-[MPt(mu-pyt)(2)(bpy)(2)](n+) (syn-[MPt], M = Pd2+, Au3+, Hpyt = pyridine-2-thiol, bpy = 2,2'-bipyridine), were synthesized as a selective geometrical isomer by stepwise complexation. X-ray analyses of the hexafluorophosphate salts of these complexes proved their dinuclear structures with short M...Pt distances (2.9084(4) angstrom for syn-[PdPt] and 2.9071(4) angstrom for syn-[AuPt]), similar to the homodinuclear complex (2.9292(2) angstrom for syn-[PtPt]). In the syn-[PdPt] crystal, two dinuclear motifs are arranged closely in a head-to-head manner with a short Pt...Pt distance (3.3757(3) angstrom), forming a dimer-of-dimer structure as in the case of syn-[PtPt], whereas the corresponding crystal of syn-[AuPt] has a discrete arrangement of the dinuclear motifs. By the isomerisation of syn-[PdPt], anti-[PdPt] with equivalent environments of the Pd2+ and Pt2+ ions was also obtained successfully. Syn-[PdPt](PF6)(2) exhibits vapochromic behaviour based on the absorption/desorption of CH3CN vapour, similar to that observed for syn-[PtPt](PF6)(2). The reversible structural transformations induced by the uptake and release of CH3CN molecules were investigated by powder and single-crystal X-ray diffraction studies. These revealed that the vapochromic behaviour was based on the interconversion between two phases, the dimer-of-dimer structure with a short Pt. Pt distance and a p-p stacked arrangement with no Pt. Pt intermolecular interaction. The introduction of the heterometal ions enabled control of the colour region: orange. red for syn-[PdPt] vs. light red. dark red for syn-[PtPt], reflecting the weaker metal-metal interaction between Pd2+ and Pt2+ ions in the dinuclear motif. In addition, these complexes were found to exhibit mechanochromic behaviour based on a crystal-to-amorphous transformation upon grinding, and the reconstruction of the crystal structures by vapour sorption.

    DOI: 10.1039/c3dt33100h

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  • Synchronic Transformation of Molecular States and Macroscopic Phases in Valence Tautomeric Complexes Reviewed

    H.-C. Chang, D. Kiriya

    Eur. J. Inorg. Chem.   130   642 - 652   2012.12

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  • Vapor-Controlled Linkage Isomerization of a Vapochromic Bis(thiocyanato)platinum(II) Complex: New External Stimuli To Control Isomerization Behavior Reviewed

    Atsushi Kobayashi, Yuki Fukuzawa, Ho-Chol Chang, Masako Kato

    INORGANIC CHEMISTRY   51 ( 14 )   7508 - 7519   2012.7

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    We synthesized a novel Pt(II)-diimine complex with a typical ambidentate thiocyanato ligand, [Pt(thiocyanato)(2)(H(2)dcbpy)] (1; H(2)dcbpy =4,4'-dicarboxy-2,2'-bipyridine), and found that the complex 1 exhibits unique linkage isomerizations with drastic color and luminescence changes driven by exposure to volatile organic chemical (VOC) vapors in the solid state. Reaction between [PtCl2(H(2)dcbpy)] and KSCN in aqueous solution at 0 degrees C enabled successful isolation of an isomer with the S-coordinated thiocyanato ligand, [Pt(SCN)(2)(H(2)dcbpy)] (1SS center dot H2O), as a nonluminescent orange solid. Interestingly, 1SS center dot H2O was isomerized completely to one isomer with the N-coordinated isothiocyanato ligand, [Pt(NCS)(2)(H(2)dcbpy)] (1NN center dot 3DMF) by exposure to DMF vapor, and this isomerization was accompanied by significant color and luminescence changes from nonluminescent orange to luminescent red. IR spectroscopy and thermogravimetric analysis revealed that adsorption of the DMF vapor and transformation of the hydrogen-bonded structure both played important roles in this vapor-induced linkage isomerization. Another isomer containing both S- and N-coordinated thiocyanato ligands, [Pt(SCN)(NCS)(H(2)dcbpy)] (1SN), was obtained as a nonluminescent yellow solid simply by exposure of 1SS center dot H2O to acetone vapor at room temperature, and about 80% of 1SS center dot H2O was found to be converted to 1SN. In the solution state, each isomer changed gradually to an isomeric mixture, but pure 1SS was regenerated by UV light irradiation (lambda(irr) = 300 nm) of an MeOH solution of the mixture. In the crystal structure of 1SN, the complex molecules were hydrogen-bonded to each other through the carboxyl groups of the H(2)dcbpy ligand and the N site of the thiocyanato ligand, whereas the 1NN molecules in the 1NN.4DMF crystal were hydrogen-bonded to the solvated DMF molecules. Competition of the hydrogen-bonding ability among the carboxyl groups of the H(2)dcbpy ligand, N and S atoms of the thiocyanato ligand, and the vapor molecule was found to be one of the most important factors controlling linkage isomerization behavior in the solid state. This unique linkage isomerization controlled by vapor can provide an outstanding vapochromic system as well as a new molecular switching function driven by vapor molecules.

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  • Coordination site-dependent cation binding and multi-responsible redox properties of Janus-head metalloligand, [Mo-V(1,2-mercaptophenolato)(3)] Reviewed

    Takeshi Matsumoto, Masanori Wakizaka, Hirokazu Yano, Atsushi Kobayashi, Ho-Chol Chang, Masako Kato

    DALTON TRANSACTIONS   41 ( 27 )   8303 - 8315   2012

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    The redox-active fac-[Mo-V(mp)(3)](-) (mp: o-mercaptophenolato) bearing asymmetric O- and S-cation binding sites can bind with several kinds of metal ions such as Na+, Mn-II, Fe-II, Co-II, Ni-II, and Cu-I. The fac-[Mo-V(mp)(3)](-) metalloligand coordinates to Na+ to form the contact ion pair {Na+(THF)(3)[fac-Mo-V(mp)(3)]} (1), while a separated ion pair, n-Bu4N[fac-Mo-V(mp)(3)] (2), is obtained by exchanging Na+ with n-Bu4N+. In the presence of asymmetric binding-sites, the metalloligand reacts with (MnCl2)-Cl-II center dot 4H(2)O, (FeCl2)-Cl-II center dot 4H(2)O, (CoCl2)-Cl-II center dot 6H(2)O, and (NiCl2)-Cl-II center dot 6H(2)O to afford UV-vis-NIR spectra, indicating binding of these guest metal cations. Especially, for the cases of the MnII and CoII products, trinuclear complexes, {M(H2O)(MeOH)-[ fac-Mo-V(mp)(3)](2)}center dot 1.5CH(2)Cl(2) (3.1.5CH(2)Cl(2) (M = Mn-II), 4.1.5CH(2)Cl(2) (M = Co-II)), are successfully isolated and structurally characterized where the M are selectively bound to the hard O-binding sites of the fac-[Mo-V(mp)(3)](-). On the other hand, a coordination polymer, {Cu-I(CH3CN)[mer-MoV(mp)(3)]}(n) (5), is obtained by the reaction of fac-[Mo-V(mp)(3)]-with [Cu-I(CH3CN)(4)]ClO4. In sharp contrast to the cases of 1, 3.1.5CH(2)Cl(2), and 4.1.5CH(2)Cl(2), the Cu-I in 5 are selectively bound to the soft S-binding sites, where each CuI is shared by two [MoV(mp) 3]-with bidentate or monodentate coordination modes. The second notable feature of 5 is found in the geometric change of the [MoV(mp) 3]-, where the original fac-form of 1 is isomerized to the mer-[Mo-V(mp)(3)](-) in 5, which was structurally and spectroscopically characterized for the first time. Such isomerization demonstrates the structural flexibility of the [Mo-V(mp)(3)](-). Spectroscopic studies strongly indicate that the association/dissociation between the guest metal ions and metalloligand can be modulated by solvent polarity. Furthermore, it was also found that such association/dissociation features are significantly influenced by coexisting anions such as ClO4- or B(C6F5)(4)(-). This suggests that coordination bonds between the guest metal ions and metalloligand are not too static, but are sufficiently moderate to be responsive to external environments. Moreover, electrochemical data of 1 and 3.1.5CH(2)Cl(2) demonstrated that guest metal ion binding led to enhance electron-accepting properties of the metalloligand. Our results illustrate the use of a redox-active chalcogenolato complex with a simple mononuclear structure as a multifunctional metalloligand that is responsive to chemical and electrochemical stimuli.

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  • Systematic structural control of multichromic platinum(II)-diimine complexes ranging from ionic solid to coordination polymer Reviewed

    Atsushi Kobayashi, Hirofumi Hara, Tsubasa Yonemura, Ho-Chol Chang, Masako Kato

    DALTON TRANSACTIONS   41 ( 6 )   1878 - 1888   2012

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    Reactions of a Pt(II)-diimine-based metalloligand Na-2[Pt(CN)(2)(4,4'-dcbpy)] (4,4'-H(2)dcbpy = 4,4'-dicarboxy-2,2'-bipyridine) with alkaline-earth metal salts Mg(NO3)(2)center dot 6H(2)O, CaCl2, SrCl2 center dot 6H(2)O, and BaBr2 center dot 2H(2)O in aqueous solution gave luminescent complexes formulated as [Mg(H2O)(5)][ Pt(CN)(2)(4,4'-dcbpy)]center dot 4H(2)O (MgPt-4 center dot 9H(2)O), {[Ca(H2O)(3)][Pt(CN)(2)(4,4'-dcbpy)]center dot 3H(2)O}(infinity) (CaPt-4 center dot 6H(2)O), {[Sr(H2O)(2)][Pt(CN)(2)(4,4'-dcbpy)]center dot H2O}(infinity) (SrPt-4 center dot 3H(2)O), and {[Ba(H2O)(2)][ Pt(CN)(2)(4,4'-dcbpy)]center dot 3H(2)O}(infinity) (BaPt-4 center dot 5H(2)O), respectively. The crystal structures of all MPt-4 complexes were determined by X-ray crystallography. In these structures, the alkaline-earth metal ions are commonly coordinated to the carboxyl groups of the [Pt(CN)(2)(4,4'-dcbpy)](2-) metalloligand. In the case of MgPt-4 center dot 9H(2)O, the Mg(II) ion is bound by five water molecules and one oxygen atom of a carboxyl group to form a neutral complex molecule [Mg(H2O) 5][Pt(CN)(2)(4,4'-dcbpy)]. In contrast, the alkaline-earth metal ion and metalloligand form two-dimensional (CaPt-4 center dot 6H(2)O) and three-dimensional (SrPt-4 center dot 3H(2)O and BaPt-4 center dot 5H(2)O) coordination networks, respectively. All fully hydrated complexes exhibited a strong phosphorescence from the triplet pi-pi* transition state. Luminescence spectroscopy revealed that MgPt-4 center dot 9H(2)O exhibited interesting multichromic (i.e., thermo-, mechano-, and vapochromic) luminescence, whereas CaPt-4 center dot 6H(2)O showed only thermochromic luminescence. The other two complexes did not exhibit any chromic behaviour. Combination analysis of powder X-ray diffraction, thermogravimetry, and IR spectroscopy suggests that the dimensionality of the coordination network contributes considerably to both the structural flexibility and luminescence properties; that is, the low-dimensional flexible coordination network formed in MPt-4 complexes with smaller alkaline-earth metal ions enables a structural rearrangement induced by thermal and mechanical stimuli and vapour adsorption, resulting in the observed multichromic behaviour.

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  • Terpyridine platinum(II) complexes containing triazine di- or tri-thiolate bridges: structures, luminescence, electrochemistry, and aggregation Reviewed

    Hua-Xin Zhang, Masako Kato, Yoichi Sasaki, Tadashi Ohba, Hiroto Ito, Atsushi Kobayashi, Ho-Chol Chang, Kohei Uosaki

    DALTON TRANSACTIONS   41 ( 37 )   11497 - 11506   2012

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    Dinuclear complexes [{Pt(trpy)}(2)(L)](PF6)(2) (trpy = 2,2': 6',2 ''-terpyridine, L = 2-octylthio-1,3,5-triazine4,6- dithiolate ion (1), L = 2-octadecylthio-1,3,5-triazine-4,6-dithiolate ion (2), L = 2-di-n-butylamino1,3,5- triazine-4,6-dithiolate ion (3)) and a trinuclear complex [{Pt(trpy)}(3)(L)](PF6)(3) (L = 1,3,5-triazine2,4,6- trithiolate ion (4)) have been synthesized and characterized. The single crystal X-ray analysis revealed that the two {Pt(trpy)}(2+) fragments in 1 and 3 adopt a syn-configuration. The Pt...Pt distances are around 4.3 angstrom, suggesting no intramolecular Pt...Pt interactions. Complexes 1-4 in acetonitrile show broad absorption bands at around 470 nm, assigned to mainly the ligand-to-ligand charge transfer ((LLCT)-L-1) from triazine thiolates to trpy based on the comparison to the related complexes and the density functional theory (DFT) calculations. The red luminescence of 1-4 in acetonitrile is attributable to emission predominantly from (LLCT)-L-3. Cyclic voltammograms of 1-3 exhibit four redox couples from -2.0 V to 0 V vs. Ag/AgCl. The two consecutive processes at around -0.70 V are assigned to the sequential reduction of two trpy ligands. This assignment was further supported by the observation of the anion radical of trpy in spectroelectrochemical experiments. The splitting of the redox potentials of two trpy ligands evidences the moderate electronic coupling interactions mediated by the triazine dithiolate bridges. Complex 2 formed a transparent red gel in CH3CN, whereas 4 produced a gel-like solid in the mixtures of CH3CN and other solvents. The interactions dominating the aggregative behaviours have been discussed based on the results of electronic absorption and emission spectroscopy.

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  • ON-OFF Switching of the Solvatochromic Behavior of a Copper(II)-Hydrazone Complex Induced by Protonation/Deprotonation Reviewed

    Mee Chang, Atsushi Kobayashi, Ho-Chol Chang, Kiyohiko Nakajima, Masako Kato

    CHEMISTRY LETTERS   40 ( 12 )   1335 - 1337   2011.12

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    A new copper(II)-hydrazone complex, [Cu(paph)Cl(CH3-OH)] (Hpaph: 2-pyridinecarboxaldehyde 2-pyridylhydrazone) (1) has been synthesized and characterized by single-crystal X-ray diffraction and UV-vis spectroscopy. This complex shows distinctive color changes by the protonation/deprotonation and exhibits interesting ON OFF switching of solvatochromic behavior on the basis of the protonation/deprotonation of the hydrazone moiety.

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  • Dimensionality Control of Vapochromic Hydrogen-Bonded Proton-Transfer Assemblies Composed of a Bis(hydrazone)iron(II) Complex Reviewed

    Mee Chang, Atsushi Kobayashi, Kiyohiko Nakajima, Ho-Chol Chang, Masako Kato

    INORGANIC CHEMISTRY   50 ( 17 )   8308 - 8317   2011.9

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    We describe the novel synthesis of a bis(hydrazone)iron(B) complex in protonated [Fe(Hpbph)(2)]Cl-2 (1) and deprotonated [Fe(pbph)(2)] (2) forms and several hydrogen-bonded proton-transfer (HBPT) assemblies having different dimensionalities of hydrogen-bonded network structures, [Fe(Hpbph)2] (CA)center dot 2CH(3)OH (3), [Fe(Hpbph)(2)](HCA)(2)center dot 2THF (4), and [Fe(Hpbph)(2)](CA)(H(2)CA)(2)center dot 2CH(3)CN (5) (Hpbph = 2-(diphenylphosphino)benzaldehyde-2-pyridylhydrazone), consisting of a deprotonated Fe(II)-hydrazone complex (2) as a proton acceptor (A) and chloranilic acid (H2CA) as a proton donor (D). The deprotonated complex 2 exhibited two-step reversible protonation reactions to form the double-protonated form 1, and the acid-dissociation constants were determined to be 7.6 and 10.3 in methanol solution. Utilizing this proton-accepting ability of 2, we succeeded in synthesizing HBPT assemblies 3, 4, and 5 from the reactions in CH3OH, THF, and CH3CN, respectively, with the same D/A ratio of H(2)CA/[Fe(pbph)(2)] = 10:1. These assemblies were found to have one-dimensional (1-D), two-dimensional (2-D), and three-dimensional (3-D) hydrogen-bonded networks with D/A ratios of 1:1, 2:1, and 3:1 for 3, 4, and 5, respectively. In 3, a 1-D hydrogen-bonded chain composed of the alternate arrangement of [Fe(Hpbph)(2)](2+) and CA(2-), {center dot center dot center dot[Fe(Hpbph)(2)](2+)center dot center dot center dot CA(2-)center dot center dot center dot}(infinity), was surrounded by solvated methanol molecules to form isolated 1-D hydrogen-bonded chains. In the HBPT assembly 4, a 2-D hydrogen-bonded sheet was formed from two types of hydrogen-bonded chains, {center dot center dot center dot[Fe(Hpbph)(2)](2+)center dot center dot center dot HCA(-)center dot center dot center dot HCA(-)center dot center dot center dot}(infinity) and {center dot center dot center dot HCA(-)center dot center dot center dot HCA(-)center dot center dot center dot}(infinity), and solvated THF molecules did not form any hydrogen bonds. In 5, two orthogonal hydrogen-bonded chains constructed from the neutral chloranilic acid molecules, {center dot center dot center dot CA2(-)center dot center dot center dot 2(H(2)CA)center dot center dot center dot}(infinity), were formed in addition to the 1-D hydrogen-bonded chain similar to that in 3, resulting in the formation of a rigid 3-D hydrogen-bonded network structure. By controlling the dimensionality of the hydrogen bond network, we found that the 2-D HBPT assembly 4 is sufficiently flexible to exhibit interesting vapochromic behavior in response to various organic vapors.

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  • Chromic Behaviors of Hexagonal Columnar Liquid Crystalline Platinum Complexes with Catecholato, 2-Thiophenolato, and Benzenedithiolato Reviewed

    Ho-Chol Chang, Kazuki Komasaka, Keisuke Kishida, Tomoki Shiozaki, Takeshi Ohmori, Takeshi Matsumoto, Atsushi Kobayashi, Masako Kato, Susumu Kitagawa

    INORGANIC CHEMISTRY   50 ( 10 )   4279 - 4288   2011.5

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    Liquid crystalline (LC) platinum(II) complexes with 1,2-thiophenolato and 1,2-benzendithiolato have been newly synthesized and investigated by spectroscopy together with the catecholato analogue. The variations in coordinating atoms (O or S or O/S mixed) lead to significant modulation in electrochemical properties in solution and absorption and emission properties of the complexes both in solution media and in the condensed phases. The asymmetric, polar mesogens/chromophores consisting of Pt(II), redox-active ligands, and alkyl-substituted bipyridine commonly play important roles not only in stabilizing the columnar LC phases, but also in fluctuations of the ground state energies. A key finding of the present work is the chromic properties of LC complexes induced by the interplay of self-association of the mesogens/chromophores and their fluctuating properties.

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  • Metal-dependent and Redox-selective Coordination Behaviors of Metalloligand [MoV(1,2-benzenedithiolato)3]– with CuI/AgI ions Reviewed

    T. Matsumoto

    Inorg. Chem.   50 ( 7 )   2859 - 2869   2011.4

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    DOI: 10.1021/ic102070c

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  • Ln-Co-Based Rock-Salt-Type Porous Coordination Polymers: Vapor Response Controlled by Changing the Lanthanide Ion Reviewed

    Atsushi Kobayashi, Yui Suzuki, Tadashi Ohba, Shin-ichiro Noro, Ho-Chol Chang, Masako Kato

    INORGANIC CHEMISTRY   50 ( 6 )   2061 - 2063   2011.3

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    We synthesized new porous coordination polymers (PCPs) {Ln(III)[Co(III)(dcbpy)(3)]center dot nH(2)O} (Ln = Nd(3+), Gd(3+); H(2)dcbpy = 4,4&apos;-dicarboxy-2,2&apos;-bipyridine) and characterized them by X-ray diffraction and vapor-adsorption measurements. These three Ln-Co-based PCPs have similar rock-salt types and highly symmetrical porous structure and show a reversible structural collapse regeneration accompanied by water-vapor desorption adsorption. Similar structural regeneration was also observed for the Gd-Co PCP upon exposure to MeOH and CH(3)CN vapors, whereas the remaining two PCPs barely responded to organic vapors.

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  • Structures and Luminescence Properties of Cyclometalated Dinuclear Platinum(II) Complexes Bridged by Pyridinethiolate Ions Reviewed

    Rie Aoki, Atsushi Kobayashi, Ho-Chol Chang, Masako Kato

    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN   84 ( 2 )   218 - 225   2011.2

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    A series of cyclometalated dinuclear platinum(II) complexes bridged by pyridine-2-thiolate (pyt) ions, [Pt-2(L)(2)-(pyt)(2)] (HL = 2-(p-tolyl)pyridine (Hptpy), 2-(2-thienyl)pyridine (Hthpy), or benzo[h]quinoline (Hbzqn)), as well as their two-electron-oxidized dinuclear platinum(III) complexes, [Pt2Cl2(L)(2)(pyt)(2)], have been synthesized and characterized. The structures and luminescence properties have been investigated by comparing them with those of the corresponding 2-phenylpyridinato (ppy) complex. All divalent complexes have similar dinuclear frameworks, with short Pt center dot center dot center dot Pt distances (ca. 2.85 angstrom), and exhibit similar intense luminescence from the triplet metal metal-to-ligand charge-transfer ((MMLCT)-M-3) state in glassy solutions. However, they provide different luminescence features reflecting their dynamic behaviors in fluid solutions and their intermolecular interactions in the solid state. [Pt-2(bzqn)(2)(pyt)(2)] containing fused aromatic rings exhibits the most sensitive features to the environment, i.e., it shows the most red-shifted luminescence spectrum in the solid state due to the intermolecular pi-pi interaction. However, in fluid solution, it provides very weak luminescence based on a rapid nonradiative deactivation mainly caused by the fluctuation of the intramolecular pi-pi repulsion between the ligands. [Pt-2(Ptpy)(2)(pyt)(2)], on the other hand, is the most stable luminophore, which always exhibits intense luminescence with an almost constant emission maximum independent of its temperature and state.

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  • Synthesis, structure and photophysical properties of a flavin-based platinum(II) complex Reviewed

    Atsushi Kobayashi, Korin Ohbayashi, Rie Aoki, Ho-Chol Chang, Masako Kato

    DALTON TRANSACTIONS   40 ( 14 )   3484 - 3489   2011

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    We synthesized a thiosemicarbazone-functionalized flavin (Fl-(H) TSC: 2-[2-(3,4-dihydro-7,8-dimethyl-2,4-dioxobenzo[g]pteridin-10(2H)-yl)ethylidene]-hydrazinecarbothioamide) and its Pt(II) complex [Pt(Fl-TSC)(2)], and characterized it using X-ray diffraction, UV-visible absorption and luminescence spectroscopy. X-ray structural analysis for [Pt(Fl-TSC)(2)] revealed that the structure of the isoalloxazine part was almost the same as that in lumiflavin (7,8,10-trimethylisoalloxazine), and the thiosemicarbazone moiety acted as a bidentate ligand to form a PtS2N2 planar conformation. UV-visible absorption and luminescence spectra of these compounds were very similar to those of riboflavin, but the emission intensity and the lifetime decreased considerably. Theoretical calculations suggested that the charge-separated state (Fl(center dot-)-TSC center dot+) contributed to the faster quenching from the (1)pi-pi* emission state.

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  • Vapour-adsorption and chromic behaviours of luminescent coordination polymers composed of a Pt(II)-diimine metalloligand and alkaline-earth metal ions Reviewed

    Hirofumi Hara, Atsushi Kobayashi, Shin-ichiro Noro, Ho-Chol Chang, Masako Kato

    DALTON TRANSACTIONS   40 ( 31 )   8012 - 8018   2011

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    Four new bimetallic coordination polymers (CPs), {M[Pt(CN)(2)(5,5&apos;-dcbpy)]center dot 4H(2)O}(n) (M = Mg(2+), Ca(2+), Sr(2+), Ba(2+); 5,5&apos;-H(2)dcbpy = 5,5&apos;-dicarboxy-2,2&apos;-bipyridine) were synthesized using four alkaline-earth metal ions and a Pt(II)-diimine metalloligand [Pt(CN)(2)(5,5&apos;-H(2)dcbpy)]. All four CPs are isomorphous with the Zn complex, {Zn[Pt(CN)(2)(5,5&apos;-dcbpy)]center dot 4H(2)O}(n), which exhibits effective metallophilic interactions between Pt(II) ions. These CPs exhibited colourful thermochromic behaviour and solid-state solvatochromic-like behaviours when suspended in various solvents. Thermogravimetric analysis and vapour-adsorption measurements revealed that the CPs can reversibly adsorb water and MeOH vapours. The emission energy of the triplet metal-metal-to-ligand charge-transfer ((3)MMLCT) state varied markedly upon guest adsorption/desorption. The chromic and vapour-adsorption properties of these CPs depend strongly on the cross-linking M(2+) ions.

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  • Acid-Base Behavior of Substituted Hydrazone Complexes Controlled by the Coordination Geometry Reviewed

    Mee Chang, Hiroyuki Horiki, Kiyohiko Nakajima, Atsushi Kobayashi, Ho-Chol Chang, Masako Kato

    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN   83 ( 8 )   905 - 910   2010.8

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    A new series of substituted hydrazone complexes, [Cu(Hpbph)I] (1), [Cu(Hpbph)PPh3]PF6 (2-PF6), [NiCl-(Hpbph)]Cl (3-Cl), [PtCl(Hpbph)]ClO4 (4-ClO4), and [PtCl(pbph)] (4b) (Hpbph = 2-(diphenylphosphino)benzaldehyde 2-pyridylhydrazone) have been synthesized and characterized. X-ray crystallography revealed that the copper(1) complexes adopt pseudo-tetrahedral geometry, while the nickel(II) and platinum(II) complexes provide square-planar forms. All the complexes exhibit distinct color changes on the basis of the deprotonation/protonation on the ligand although their acid/base behaviors are largely different. The acidity constants (pK(a)) in methanol were determined to be 11.4 (1), 12.5 (2), 7.7 (3), and 6.7 (4). The results indicate that the dissociation of the proton on the ligand strongly depends on the ligand deformation controlled by the coordination geometry of the complexes and ancillary ligands also somewhat affect the acidity.

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  • Modulable cooperativity in a valence tautomeric complex functionalized with branched alkyl chains Reviewed

    Daisuke Kiriya, Kohei Nakamura, Susumu Kitagawa, Ho-Chol Chang

    CHEMICAL COMMUNICATIONS   46 ( 21 )   3729 - 3731   2010

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    Functionalization of a cobalt/dioxolene complex with branched, asymmetric alkyl chains promotes non-cooperative and cooperative valence tautomerisms synchronized with thermodynamically favoured crystal-to-melt and kinetically generated glass-to-melt phase transitions, respectively, depending on the degree of crystallinity.

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  • Voltammetric Antioxidant Analysis in Mineral Oil Samples Immobilized into Boron-Doped Diamond Micropore Array Electrodes Reviewed

    Xiaohang Zhang, Christopher A. Paddon, Yohan Chan, Philip C. Bulman-Page, Paul S. Fordred, Steven D. Bull, Ho-Chol Chang, Nadeem Rizvi, Frank Marken

    ELECTROANALYSIS   21 ( 12 )   1341 - 1347   2009.6

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    Mineral oil microdroplets containing the model antioxidant N,N-didodecyl-N&apos;,N&apos;-dietliyl-phenylene-diamine (DDPD) are immobilized into a 100 x 100 pore-array (ca. 10 mu m individual pore diameter, 100 mu m pitch) in a boron-doped diamond electrode surface. The robust diamond surface allows pore filling, cleaning, and reuse without damage to the electrode surface. The electrode is immersed into aqueous electrolyte media, and voltammetric responses 1 or the oxidation of DDPD are obtained. In order to further improve the current responses, 20 wt% of carbon nanofibers are co-deposited with the oil into the pore array. Voltammetric signals are consistent with the oxidation of DDPD and the associated transfer of perchlorate anions (in aqueous 0.1 M NaClO(4)) or the transfer of protons (in aqueous 0.1 M HClO(4)). From the magnitude of the current response, the DDPD content in the mineral oil can be determined down to less than 1 wt% levels. Perhaps surprisingly, the reversible (or midpoint) potential for the DDPD oxidation in mineral oil (when immersed in 0.1 NaClO(4)) is shown to be concentration-dependent and to shift to more positive potential values for more dilute DDPD in mineral oil solutions. An extraction mechanism and the formation of a separate organic product phase are proposed to explain this behavior.

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  • Assembled Functional Chemistry of Redox-active Complexes Reviewed

    H.-C. Chang

    Bull. Jpn. Soc. Coord. Chem.   53   24 - 32   2009.5

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    The present contribution reviews the synthesis and properties of complexes including redox-active dioxolene ligands as well as its analogues, diiminosemiquinonato, and dithiolene ligands. This review first summarizes the structural and electronic features of new molecular complexes as a building block for constructing electronically labile molecular assemblies. Ligand-based mixed valence (LBMV) state has been realized both in mononuclear chromium and pentanuclear cobalt complexes. Second topic will be on the construction of molecular assemblies integrated by intermolecular stacking or charge-transfer interactions, clusterization, and ligand-unsupported M-M bonds. The formation of a thin film which acts as an active layer of a field-effect transistor will also be described. Final attention is drawn to the use of the redox-active complexes for the construction of stimuli-responsive molecular assemblies. The review will demonstrate recent developments of molecular assemblies that show macroscopic phase transition or phase transformation triggered by intramolecular electron transfer or redox reaction in solid, liquid, and liquid crystals.

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    Other Link: https://jlc.jst.go.jp/DN/JALC/00337206410?from=CiNii

  • Polymorph-Dependent Molecular Valence Tautomerism Synchronized with Crystal-Melt Phase Transitions Reviewed

    Daisuke Kiriya, Ho-Chol Chang, Kohei Nakamura, Daisuke Tanaka, Ko Yoneda, Susumu Kitagawa

    CHEMISTRY OF MATERIALS   21 ( 9 )   1980 - 1988   2009.5

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    This paper describes a molecular valence tautomeric (VT) bistability synchronized with polymorphic crystal-melt phase transitions of a newly designed VT complex, [Co(C9Espy)(2)(3,6-DTBQ)(2)] (CoC9Espy, C9Espy = dinonyl-pyridine-3,5-dicarboxylate and 3,6-DTBQ = 3,6-di-tert-butyl-semiquinonate (3,6-DTBSQ) or catecholate (3,6-DTBCat)). Two polymorphic crystals which are the thermodynamically stable phase (K1) and the kinetically stable phase (K2), commonly containing a [low spin-Co(III)(C9Espy)(2)(3,6-DTBSQ)(3,6-DTBCat)] (ls-[Co(III)]) tautomer with a low-spin Co(III) atom and mixed-valence ligands. These polymorphic crystals show a molecular VT interconversion that is synchronized with crystal-to-melt phase transitions at different temperatures, 368.2 and 362.6 K for the ls-[Co(III)]subset of K1 and the ls-[Co(III)]subset of K2 phases, respectively. Interestingly, the ls-[Co(III)]subset of K2 obtained from a melt of a [high spin-Co(II)(C9Espy)(2)(3,6-DTBSQ)(2)] (hs-[Co(II)]) tautomer with a high-spin Co(II) atom with two 3,6-DTBSQ exhibits a double-melting phenomenon that includes, in part, the thermodynamically unfavorable hs-[Co(II)]-to-ls-[Co(III)] VT interconversion. Eventually, three types of VT interconversions synchronized with macroscopic crystal-melt phase transitions appear either in equilibrium or nonequilibrium conditions: (1) the thermodynamically stable ls-[Co(III)]subset of K1 to the hs-[Co(II)]subset of melt, (2) the metastable ls-[Co(III)]subset of K2 to the hs-[Co(II)]subset of melt, and (3) the relaxing process of the metastable hs-[Co(II)]subset of melt to the thermodynamically stable ls-[Co(III)]subset of K1. A new strategy for simultaneous control of molecular states and macroscopic phases using thermodynamically and kinetically formed polymorphic crystalline phases is presented.

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  • Allosteric binding of amino alcohols and diamines by dimeric zinc biladienone Reviewed

    Tomofumi Shimizu, Naomi Asano, Tadashi Mizutani, Ho-Chol Chang, Susumu Kitagawa

    TETRAHEDRON LETTERS   50 ( 5 )   536 - 539   2009.2

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    A zinc complex of biladienone forms a dimer in toluene and dichloromethane. Binding of two molecules of amino alcohols and diamines to the dimer occurs cooperatively, with the first binding constant being two orders OF three orders of magnitude smaller than the second binding constant. Simple amines such as butylamine did not show Such cooperative binding. We suggest the mechanism of cooperative binding, where the amino or hydroxyl group in amino alcohols or diamines prevents the dinner dissociation to result in the less tight binding for the first guest, while the binding of the second ligand caused dimer dissociation to release strain in the intermediate complex. (c) 2008 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.tetlet.2008.11.057

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  • Bimodal three-membered valence tautomerism of an alkyl chain-functionalized manganese dioxolene complex Reviewed

    Daisuke Kiriya, Kohei Nakamura, Ho-Chol Chang, Susumu Kitagawa

    CHEMICAL COMMUNICATIONS   ( 27 )   4085 - 4087   2009

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    A novel alkyl chain-functionalized manganese complex with dioxolene ligands shows a bimodal three-membered valence tautomerism, one of which synchronizes with a cooperative solid-melt phase transition and the other occurs in the melt noncooperatively.

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  • Dynamic torsional motion of a diruthenium complex with four homo-catecholates and first synthesis of a diruthenium complex with mixed-catecholates Reviewed

    Ho-Chol Chang, Katsunori Mochizuki, Susumu Kitagawa

    JOURNAL OF MOLECULAR STRUCTURE   890 ( 1-3 )   303 - 308   2008.11

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    Dynamic properties of a diruthenium complex with ligand-unsupported Ru-Ru triple bonds, Na(2)[Ru(2)(3,6-DTBCat)(4)] (1), were studied using variable-temperature (1)H NMR. Structural freedom derived from the ligand-unsupported structure leads to torsional motion about the Ru-Ru bonds in THF and in DMF. The observed solvent dependency corresponds to the electrostatic interactions between the diruthenium complex and Na(+) counter cations, which are sensitive to the polarity of solvents. In addition, a new diruthenium complex, [{Na(THF)(2)(H(2)O))[Na(THF)(0.5)(H(2)O)}{Ru(2)(3,6-DTBCat)(2)(H(4)Cat)(2)}] (2-2.5THIF center dot 2H(2)O), with a ligand-unsupported Ru-Ru bond surrounded by two different kinds of catecholate derivatives, has been synthesized and crystallographically characterized. The complex, which was characterized by single-crystal structural analysis, will provide an opportunity to investigate not only static molecular structures but also dynamic physicochemical properties in comparison with analogues containing four identical catecholate derivatives. (c) 2008 Elsevier B.V. All rights reserved.

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  • Ambipolar, Single-Component, Metal-Organic Thin-Film Transistors with High and Balanced, Hole and Electron Mobilities Reviewed

    S.-i. Noro

    Adv. Mat.   20 ( 18 )   3399 - 3403   2008.9

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  • Molecule-based valence tautomeric bistability synchronized with a macroscopic crystal-melt phase transition Reviewed

    Daisuke Kiriya, Ho-Chol Chang, Susumu Kitagawa

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   130 ( 16 )   5515 - 5522   2008.4

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    Here, we show a synchronic bistability of valence tautomeric (VT) molecular interconversion and a macroscopic crystal-melt phase transition in long alkoxy-functionalized cobalt-dioxolene complexes. Studies have been carried out for a novel series of complexes, [Co(CnOPY)(2)(3,6-DTBQ)(2)] (3,5-dialkoxy(CnH2 On+1-; n = 9, 12, and 17)pyridine (CnOpy) and 3,6-di-tert-butyl semiquinonate or catecholate ligands (3,6-DTBQ)). All complexes show the molecular VT interconversion with thermal hysteresis attributed to the synchronous crystal-melt phase transition. Thermodynamic analysis has revealed that the molecular VT interconversion is restricted over 50 K and crystal-melt phase transition is accelerated about 50 K by the synchronicity. The synchronicity is attributed to enthalpic and entropic effects of the alkoxy chains in the crystalline phase of the one tautomer and the melt phase of the other, respectively. Our results show efficient chemical and thermodynamic strategies to combine molecule-based and macroscopic bistabilities.

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  • A redox-active columnar metallomesogen and its cyclic voltammetric responses Reviewed

    Ho-Chol Chang, Tomoki Shiozaki, Akiko Kamata, Keisuke Kishida, Takeshi Ohmori, Daisuke Kiriya, Takae Yamauchi, Hirotaka Furukawa, Susumu Kitagawa

    JOURNAL OF MATERIALS CHEMISTRY   17 ( 39 )   4136 - 4138   2007

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    We demonstrate a strategy that appears particularly well suited for the design of redox-active liquid crystals and also constitutes the first demonstration of cyclic voltammetric responses of a metallomesogen in the columnar liquid crystalline phase.

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  • Structural and spectroscopic characterization of a diruthenium o-dioxolene complex possessing a singly occupied molecular orbital delocalized over the entire molecule, [Ru-2(3,6-DTBDiox)(4)](-) Reviewed

    K Mochizuki, T Kawamura, HC Chang, S Kitagawa

    INORGANIC CHEMISTRY   45 ( 10 )   3990 - 3997   2006.5

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    Chemical oxidation of [Ru-2(6+)(3,6-DTBCat)(4)](2-) affords [n-Bu4N][Ru-2(3,6-DTBDiox)(4)]center dot acetone (2 center dot acetone). The oxidized species was characterized by X-ray crystallographic analysis and EPR, and the delocalization of the unpaired electron over the entire molecule was indicated. This example showed that the utilization of redox-active ligands into a Ru-2 complex expanded the degree of freedom in the electronic structure. DFT calculations support this view, and the spin population was estimated to be approximately 18% and 82% for the Ru-2 core and the four dioxolene ligands, respectively.

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  • Tuning of the spin states in trinuclear cobalt compounds of pyridazine by the second simple bridging ligand Reviewed

    T Yi, C Ho-Chol, S Gao, S Kitagawa

    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY   ( 7 )   1381 - 1387   2006.4

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    Three novel trinuclear cobalt(II) compounds of pyridazine, [CO3(mu-OH)(2)(P-pdz)(4)(pdz)(2)(NO3)(2)(H2O)(2)]-(NO3)(2)(.)(THF)(.)2(MeOH) (1), [Co-3 (mu-OH)(2)(mu-pdz)(4)(pdz)(4) (NO3)(2)] (.) [Co-3 (mu-OH)(2)(P-pdz)(4)(MeOH)(4)(NO3)(2)](.)(NO3)(4) (2), and [Co-3(P-pdz)(4)(mu-NCS)(2)(pdz)(2)(NCS)(4)](.)2MeOH (3) (pdz = pyridazine), have been synthesized and characterized. The structures of all three compounds consist of centrosymmetric trimer building blocks bridged by the two nitrogen atoms of the pyridazine ligands and the second small bridging anions (hydroxide in I and 2, and end-on thiocyanate in 3). The two-atom bridging modes of the pyridazine ligand in 1 and 2 are unusual: each bridging pyridazine ligand affords two nitrogen donors to two metal ions with different bond lengths. This results in two kinds of spin states for the cobalt(II) atoms in 1. Magnetic measurements show a typical antiferromagnetic interaction between the high-spin metals in 3, but an unusual magnetic coupling through two high- and one low-spin cobalt atoms within the trimer in 1. An irregular spin states structure is also observed in 1 at low temperature. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006).

    DOI: 10.1002/ejic.200500741

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  • Polytypic phase transition in alkyl chain-functionalized valence tautomeric complexes Reviewed

    D Kiriya, HC Chang, A Kamata, S Kitagawa

    DALTON TRANSACTIONS   ( 11 )   1377 - 1382   2006.3

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    A novel series of valence tautomeric (VT) complexes, [Co(Cnbpy)(3,5-DTBQ)(2)] (Cnbpy = 4,4'-dialkyl-2,2'-bipyridine (alkyl = (CnH2n+1) where n = 0 (CoCObpy), 1 (CoC1bpy), 5 (CoC5bp), 9 (CoC9bpy) and 13 (CoC13bpy); 3,5-DTBQ = 315-di-tert-butylsemiquinonate or catecholate), including two previously reported complexes (CoCObpy and CoC1bpy), were systematically prepared and their properties examined. Introduction of alkyl groups into VT chromophores leads to unexpected variations in the VT process, depending on the lengths of the alkyl chains. An even more interesting observation is that significant polytypic phase transitions with crystallographic symmetry changes accompanying the abrupt VT conversion are induced for the first time in CoC9bpy and CoC13bpy.

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  • Redox-active columnar metallomesogens and their electrochemical responces

    Chang Ho-Chol, Shiozaki Tomoki, Ohmori Takeshi, Kishida Keisuke, Kitagawa Susumu

    Proceedings of Japanese Liquid Crystal Society Annual meeting   2006   97 - 97   2006

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    A first example of redox-active metallomesogen with catechol was designed using the branched alkyl chains. A hexagonal columnar ordered phase (Colho) is fairly stable over 161 degeeC from 31 degreeC. The direct electrochemical study on the Colho phase illustrates that the redox process occurred at a three-phase junction of the Colho, the electrode, and the electrolyte solution.

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  • Synthesis, structures, and magnetic properties of the copper(II), cobalt(II), and manganese(II) complexes with 9-acridinecarboxylate and 4-quinolinecarboxylate ligands Reviewed

    XH Bu, ML Tong, YB Xie, Li, JR, HC Chang, S Kitagawa, J Ribas

    INORGANIC CHEMISTRY   44 ( 26 )   9837 - 9846   2005.12

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    To explore the relationships between the structures of ligands and their complexes, we have synthesized and characterized a series of metal complexes with two structurally related ligands, 9-acridinecarboxylic acid (HL1) and 4-quinolinecarboxylate acid (HL2), [Cu-2(mu(2)-OMe)2(L-1)2(H2O)(0.69)](n) 1, [Cu-2(L-1)(4)(CH3OH)(2)] 2, [Cu-3(L-1)(6)(CH3OH)(6)]center dot 3H(2)O 3, [Mn-3(L-1)(6)(CH3OH)(6)]center dot 3H(2)O 4, [Co-3(L-1)(6)(CH3OH)(6)]center dot 3H(2)O 5, [Cu(L-2)(2)], 6, [Mn(L-2)(2)(H2O)](n) 7, and [Co(L-2)(2)(H2O)](n) 8. 1 is a three-dimensional (3D) polymer with an interpenetrating NbO type network showing one-dimensional (1 D) channels, whereas 2 and 3 take bi- and trinuclear structures, respectively, because of the differences in basicity of the reaction systems in preparing the three complexes. 4 and 5 have trinuclear structures similar to that of 3. In 1-5, ligand L-1 performs different coordination modes with NO-bridging in 1 and O,O'-bridging in 2-5, and the metal ions also show different coordination geometries: square planar in 1, square pyramidal in 2, and octahedral in 3-5. 6 has a two-dimensional structure containing (4,4) grids in which L-2 adopts the NO-bridging mode and the Cull center takes square planar geometry. 7 and 8 are isostructural complexes showing 1 D chain structures, with L-2 adopting the O,O-bridging mode. In addition, the intermolecular O-H center dot center dot center dot N hydrogen bonds and pi-pi stacking interactions further extend the complexes (except 1 and 6), forming 3D structures. The magnetic properties of 2-7 have been investigated and discussed in detail.

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  • Effect of countercations on the structural isomerization of a dianionic diruthenium complex with a ligand-unsupported Ru-Ru bond Reviewed

    K Mochizuki, HC Chang, T Kawamura, S Kitagawa

    CHEMISTRY LETTERS   34 ( 12 )   1662 - 1663   2005.12

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    Isomers of [Ru-2(III,III)(3,5-DTBCat)(4)](2-) (3,5-DTBCat(2-) = 3,5 -di-tert-butylcatecholate) were successfully characterized. It is found that the isomerization from the kinetically stable cis,cis form to the thermodynamically stable trans,trans form is caused not only by heating but also by the cation exchange from Na+ to n-BU4N+, revealing that the isomerization is regulated by the specific cation-anion interactions.

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  • Metal-organic thin-film transistor (MOTFT) based on bis(o-diiminobenzosemiquinonate) nickel(II) complex Reviewed

    S Noro, HC Chang, T Takenobu, Y Murayama, T Kanbara, T Aoyama, T Sassa, T Wada, D Tanaka, S Kitagawa, Y Iwasa, T Akutagawa, T Nakamura

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   127 ( 28 )   10012 - 10013   2005.7

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    DOI: 10.1021/ja052663s

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  • Formation of 3D networks by H-bonding from novel trinuclear or 1D chain complexes of zinc(II) and cadmium(II) with isonicotinic acid analogues and the effects of pi-pi stacking Reviewed

    XH Bu, ML Tong, Li, JR, HC Chang, JL Li, S Kitagawa

    CRYSTENGCOMM   7 ( 67 )   411 - 416   2005.6

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    The reactions of isonicotinic acid analogues, 4-quinolinecarboxylic acid (HL1) and 9-acridinecarboxylic acid (HL2) with M(NO3)(2) (M = Zn-II and Cd-II) in the presence of Et3N in MeOH (or EtOH) led to the formation of four new complexes, [Zn(L-1)(2)(H2O)](infinity) (1), [Zn(L-2)(2)(MeOH)(2)](3)center dot(H2O)(1.5) (2) and [Cd(L-2)(2)(MeOH)(2)](3)center dot(H2O)(1.5) (3) and [Cd(L-2)(2)(EtOH)(2)](3)center dot(H2O)(0.5) (4). Single crystal X-ray diffraction analyses revealed that the Zn-II and Cd-II complexes of the same ligand (L-1 or L-2) are isostructural, with 1 taking a 1D chain structure, with 2-4 being trinuclear complexes. In such complexes, the carboxylate groups adopt a bidentate syn, syn-bridging coordination fashion to bridge adjacent metal centers. The N donors do not take part in the coordination, but form O-H center dot center dot center dot N hydrogen bonds with the coordinated water or MeOH (or EtOH), leading to the formation of 3D frameworks. The effects of pi-pi stacking and the structural differences between these complexes and those with isonicotinic acid were also discussed.

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  • Effects of countercations on the structures and redox and spectroscopic properties of diruthenium catecholate complexes with ligand-unsupported Ru-Ru bonds Reviewed

    HC Chang, K Mochizuki, S Kitagawa

    INORGANIC CHEMISTRY   44 ( 11 )   3810 - 3817   2005.5

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    The molecular structures and physicochemical properties of diruthenium complexes with ligand-unsupported Ru-Ru bonds, generally formulated as [A(2){Ru-2(DTBCat)(4)}] (DTB = 3,5- or 3,64-tert-butyl; Cat(2) = catecholate), were studied in detail by changing the countercations. First, the binding structures of the cations in a family of [{A(DME)n}(2){Ru-2(3,5-DTBCat)(4)}] (n = 2 for A(+) = Li+ and Na+ and n = 1 for A(+) = K+ and Rb+) were systematically examined to reveal the effects of the cations on the molecular structures and electrochemical properties. Second, the complex (n-Bu4N)(2)[Ru-2(3,6-DTBCat)(4))]with a cation-free structure was synthesized using tetra-n-buyammonium cations. The complex clearly demonstrates first that the ligand-unsupported Ru-Ru bonds are essentially stabilized by the dianionic nature of the catecholate derivatives without any other bridging or supporting species. In contrast, the redox potentials and absorption spectra of the complexes can sensitively respond to the countercations depending upon the polarity of the solvents.

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  • Substituent-directed structural and physicochemical controls of diruthenium catecholate complexes with ligand-unsupported Ru-Ru bonds Reviewed

    HC Chang, K Mochizuki, S Kitagawa

    INORGANIC CHEMISTRY   44 ( 11 )   3799 - 3809   2005.5

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    A family of diruthenium complexes with ligand-unsupported Ru-Ru bonds has been systematically synthesized, and their crystal structures and physical properties have been examined. A simple, useful reaction between Ru-2(OAc)(4)Cl (OAc- = acetate) and catechol derivatives in the presence of bases afforded a variety of diruthenium complexes, generally formulated as [Na-n{Ru-2(R(4)Cat)(4)}] (n = 2 or 3; R-4 = -F-4, -Cl-4, -Br-4, -H-4, -3,5-di-t-Bu, and -3,6-di-t-Bu; Cat(2-) = catecholate). The most characteristic feature of the complexes is the formation of short ligand-unsupported Ru-Ru bonds (2.140-2.273 angstrom), These comprehensive studies were carried out to evaluate the effects of the oxidation states and the substituents governing the molecular structures and physicochemical properties. The Ru-Ru bond distances, rotational conformations, and bending structures of the complexes were successfully varied. The results presented in this manuscript clearly demonstrate that the complexes with ligand-unsupported Ru-Ru bonds can sensitively respond to redox reactions and ligand substituents on the basis of the greater degree of freedom in their molecular structures.

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  • Formation of a ligand-based mixed-valence cluster triggered by dehydration condensation of semiquinonates with o-phenylenediamines Reviewed

    HC Chang, N Nishida, S Kitagawa

    CHEMISTRY LETTERS   34 ( 3 )   402 - 403   2005.3

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    A tetrameric [Co-II(phenSQ)(2)](4) with homovalent semiquinonates reacts with o-phenylenediamines to give a ligand-based mixed-valence pentanuclear cluster [{Co-5(II)(phenSQ)(4)(phen-Cat)(3)(THF)(3)(H2O)}center dot THF], containing two differently charged ligands, whose formation is triggered by a dehydration condensation reaction between the semiquinonates and o-phenylenediamines.

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  • Porous lanthanide-organic framework with zeolite-like topology Reviewed

    TK Maji, G Mostafa, HC Chang, S Kitagawa

    CHEMICAL COMMUNICATIONS   ( 19 )   2436 - 2438   2005

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    Two novel isomorphous porous frameworks of Ln( III), {[Ln(2)(imidc)(2)(H2O) (3)](H2O)}(n), [Ln = Gd(III) (1) and Er(III) (2)] have been synthesized hydrothermally using multifunctional 4,5-imidazoledicarboxylic acid (imidc) as a connector; they have a zeolite-like network topology which can provide another form upon dehydration, and exhibit selective adsorption properties for H2O over N-2, CO2 and MeOH.

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  • Effect of the metal-assisted assembling mode on the redox states of hexaazatriphenylene hexacarbonitrile Reviewed

    S Furukawa, T Okubo, S Masaoka, D Tanaka, HC Chang, S Kitagawa

    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION   44 ( 18 )   2700 - 2704   2005

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    DOI: 10.1002/anie.200462962

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  • A facile and versatile preparation of bilindiones and biladienones from tetraarylporphyrins Reviewed

    T Yamauchi, T Mizutani, K Wada, S Horii, H Furukawa, S Masaoka, HC Chang, S Kitagawa

    CHEMICAL COMMUNICATIONS   ( 10 )   1309 - 1311   2005

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    Bilindiones and biladienones carrying aryl groups at the meso positions were prepared using coupled oxidation reactions of iron tetraarylporphyrins in 20 - 63% yield.

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  • Cover Picture: Expanding and Shrinking Porous Modulation Based on Pillared-Layer Coordination Polymers Showing Selective Guest Adsorption (Angew. Chem. Int. Ed. 25/2004)

    Tapas Kumar Maji, Kazuhiro Uemura, Ho-Chol Chang, Ryotaro Matsuda, Susumu Kitagawa

    Angewandte Chemie International Edition   43 ( 25 )   3205 - 3205   2004.6

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    DOI: 10.1002/anie.200490079

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  • Metal-complex assemblies constructed from the flexible hinge-like ligand H(2)bhnq: Structural versatility and dynamic behavior in the solid state Reviewed

    K Yamada, S Yagishita, H Tanaka, K Tohyama, K Adachi, S Kaizaki, H Kumagai, K Inoue, R Kitaura, HC Chang, S Kitagawa, S Kawata

    CHEMISTRY-A EUROPEAN JOURNAL   10 ( 11 )   2648 - 2660   2004.6

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    Novel metal-complex assemblies constructed from the flexible hinge-like ligand H(2)bhnq (H(2)bhnq= 2,2'-bi(3-hydroxy-1,4-naphthoquinone)) have been synthesized. The X-ray crystal structures of these compounds reveal that four types of architectures are accessible by variation of the metal ions. In copper(II) compounds 1-3, the chelating bhnq(2-) ions bridge copper(II) centers to form one-dimensional zigzag chains. The chains of 1-3 are arranged by hydrogen-bonding interactions and stacking interactions to produce porous structures. Cobalt(II) and zinc(II) compounds 4 and 5 form one-dimensional helical chains. In 4 and 5, the crystal packing induces spontaneous resolution of the helical chains with chiral cavities formed perpendicular to the helices. Nickel(II) compounds 6 and 7 form cyclic tetramers. The fourth architecture, a dimer (compound 8), is obtained by the reaction of zinc(II) and bhnq(2-) in MeOH. In these compounds, changes of the dihedral angles and the metal-coordination mode of the bhnq(2-) ion induce the structural versatility. The assemblies of the zigzag chains of the copper(II) compounds exhibit reversible vapochromic behavior. UV/Vis, powder X-ray diffraction, EPR, and adsorption isotherm measurements indicate that this vapochromic behavior is based on the hinge-like flexibility of the bhnq(2-) ion.

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  • Magnetism of a one-dimensional array of oxygen in a micro-porous metal-organic solid Reviewed

    A. Matsuo, T. C. Kobayashi, M. Suzuki, K. Kindo, R. Kitaura, R. Matsuda, H. -C. Chang, S. Kitagawa

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   272 ( 272-276 )   E643 - E645   2004.5

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    The magnetic properties of molecular oxygen adsorbed in the micro-porous metal-organic solids have been investigated. Adsorbed O-2 molecules form a ladder structure in the nanochannels of CPL-1. The temperature dependence of susceptibility and the high-field magnetization process indicate the nonmagnetic ground state of the adsorbed O-2 at low temperatures. (C) 2003 Elsevier B. V. All rights reserved.

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  • Temperature-controlled hydrothermal synthesis of a 2D ferromagnetic coordination bilayered polymer and a novel 3D network with inorganic CO3(OH)(2) ferrimagnetic chains Reviewed

    ML Tong, S Kitagawa, HC Chang, M Ohba

    CHEMICAL COMMUNICATIONS   ( 4 )   418 - 419   2004.2

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    A 2D bilayered ferromagnetic coordination polymer, generated by lower-temperature hydrothermal reactions of cobalt(II) salt with the 3,4-pyridinedicarboxylate dianion, was controlled to transform into a 3D magnetic coordination network with Co-3(OH)(2) ferrimagnetic chains at a higher temperature.

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  • Third-order nonlinear optical properties of soluble Cr(III)-dioxolene complexes Reviewed

    S Noro, T Sassa, T Aoyama, HC Chang, S Kitagawa, T Wada

    LINEAR AND NONLINEAR OPTICS OF ORGANIC MATERIALS IV   5517 ( 5571 )   12 - 19   2004

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    We synthesized novel ligand-based mixed valence (LBMV) Cr-III-dioxolene complexes, [Cr(X(4)SQ)(X(4)Cat)(4,4'-di-tertbutyl-2,2'-bpy)] (SQ = semiquinone, Cat = catecohol, 2,2'-bpy = 2,2'-bipyridine; X = Cl (2a) and Br (2b)) and [Cr(X(4)SQ)(X(4)Cat)(4,4'-dinonyl-2,2'-bpy)] (X = Cl (3a) and Br (3b)), and prepared thin films for investigating their third-order nonlinear optical (NLO) properties in terms of the mixed valence states. Electronic absorption spectra of these complexes in solution and solid states showed an intervalence charge-transfer (IVCT) band from Cat(2-) to SQ(.) at the IR region, indicating of a coexistence of SQ and Cat ligands, namely, LBMV state of the complexes. These complexes were well soluble in nonpolar organic solvent, which allowed us to prepare thin films by spin coating. The obtained films showed the electronic absorption spectra similar to those in solution and were amorphous because of steric hindrance of halogen and alkyl substituents in o-dioxolene and 2,2'-bpy moieties, respectively. The chi((3)) values of the films of 3a and 3b with a thickness of 30 similar to 40 nm were determined for 1.0 x 10(-12) esu at 1.907 mum.

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  • Expanding and shrinking porous modulation based on pillared-layer coordination polymers showing selective guest adsorption Reviewed

    TK Maji, K Uemura, HC Chang, R Matsuda, S Kitagawa

    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION   43 ( 25 )   3269 - 3272   2004

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    DOI: 10.1002/anie.200453923

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  • A neutral 3D copper coordination polymer showing 1D open channels and the first interpenetrating NbO-type network Reviewed

    XH Bu, ML Tong, HC Chang, S Kitagawa, Batten, SR

    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION   43 ( 2 )   192 - 195   2004

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    DOI: 10.1002/anie.200352024

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  • Syntheses and crystal structures of three one-dimensional copper(II) complexes constructed by salicylate and 4,4 '-bipyridine: ladder, zig-zag, and linear polymeric assembly Reviewed

    LG Zhu, S Kitagawa, H Miyasaka, HC Chang

    INORGANICA CHIMICA ACTA   355 ( 355 )   121 - 126   2003.11

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    Syntheses and crystal structures of three new compounds {trans-[Cu(Hsal)(2)(4,4'-bipy)](DMF)}(n) (1), {cis-[Cu(Hsal)(2)(4,4'-bipy)](2H(2)O)}(n) (2), and [Cu-2(Hsal)(4)(4,4'-bipy)](n) (3) are reported. These three compounds have trans-, cis-, and dimer geometries bearing a common motif [Cu(Hsal)(2)(4,4-bipy)(n)] leading to ladder, zig-zag, and linear one-dimensional (1-D) networks, respectively. The Cu...Cu distances separated by 4,4'-bipy are different in these three compounds, which leads to an extension structure in compound 3 and a compact structure in compound 2. Conformations of 4,4'-bipy ligands in these three compounds are also different. In compound I there is stacking of the bidentate salicylate and the bridging salicylate from another molecule. There is also stacking of salicylate and 4,4'-bipy from another molecule in compound 2. (C) 2003 Elsevier B.V. All rights reserved.

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  • Rational design of a ferromagnetic trinuclear copper(II) complex with a novel in-situ synthesised metalloligand Reviewed

    ML Tong, YM Wu, YX Tong, XM Chen, HC Chang, S Kitagawa

    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY   ( 13 )   2385 - 2388   2003.7

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    An interesting ferromagnetic linear trinuclear copper(II) compound containing an in-situ synthesised functional ligand has been rationally obtained and crystallographically characterised, confirming a new route to magnetic polynuclear clusters. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).

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  • Cation-templated construction of three-dimensional alpha-Po cubic-type [M(dca)(3)](-) networks. Syntheses, structures and magnetic properties of A[M(dca)(3)] (dca = dicyanamide; for A = benzyltributylammonium, M = Mn2+, Co2+; for A = benzyltriethylammonium, M = Mn2+, Fe2+) Reviewed

    ML Tong, J Ru, YM Wu, XM Chen, HC Chang, K Mochizuki, S Kitagawa

    NEW JOURNAL OF CHEMISTRY   27 ( 5 )   779 - 782   2003

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    A new family of three-dimensional cubic-like [M(dca)(3)](-) networks ( dca = dicyanamide) templated by appropriate cations has been constructed and structurally characterized by X-ray crystallography.

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  • A novel three-dimensional coordination polymer constructed with mixed-valence dimeric copper(I,II) units Reviewed

    ML Tong, LJ Li, K Mochizuki, HC Chang, XM Chen, Y Li, S Kitagawa

    CHEMICAL COMMUNICATIONS   ( 3 )   428 - 429   2003

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    A novel three-dimensional coordination polymer with a mixed-valence localized copper(I, II) dimeric unit, [Cu-2(4-pya) (3)](n) (4-pya = 4-pyridinecarboxylate), was hydrothermally synthesized via a simultaneous in-situa redox and hydrolysis reaction of Cu(II) and 4-cyanopyridine and crystallographically characterized to be a twofold interpenetrated three-dimensional coordination network with a cubic [Cu-16(4-pya)(12)] building unit.

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  • PB16 Syntheses of Novel Transition Metal Complexes toward Redox-active Metallomesogens

    CHANG Ho-Chol, KAMATA Akiko, FURUKAWA Hirotaka, MOCHIZUKI Katsunori, KITAGAWA Susumu

    Proceedings of Japanese Liquid Crystal Society Annual meeting   2003   389 - 390   2003

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    Novel mono/trinuclear palladium/platinum complexes have been synthesized and characterized by X-ray diffraction, electrochemical, and thermogravimetric analyses. All the complexes possess catecholate derivatives, which have been known to show rich redox activity. Almost complexes show multi-step thermal phase transitions, and each transition was studied by XRPD and DSC measurements. Interestingly, the complexes demonstrate redox activity based on the electronically labile nature of the catecholate derivatives. The results obtained in this study clearly suggest that the complexes would be candidates for redox-active metallomesogens.

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  • Formation of a one-dimensional array of oxygen in a microporous metal-organic solid Reviewed

    R Kitaura, S Kitagawa, Y Kubota, TC Kobayashi, K Kindo, Y Mita, A Matsuo, M Kobayashi, HC Chang, TC Ozawa, M Suzuki, M Sakata, M Takata

    SCIENCE   298 ( 5602 )   2358 - 2361   2002.12

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    We report the direct observation of dioxygen molecules physisorbed in the nanochannels of a microporous copper coordination polymer by the MEM (maximum entropy method)/Rietveld method, using in situ high-resolution synchrotron x-ray powder diffraction measurements. The obtained MEM electron density revealed that van der Waals dimers of physisorbed O(2) locate in the middle of nanochannels and form a one-dimensional ladder structure aligned to the host channel structure. The observed O-O stretching Raman band and magnetic susceptibilities are characteristic of the confined O(2) molecules in one-dimensional nanochannels of CPL-1 (coordination polymer 1 with pillared layer structure).

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  • Pseudo-polyrotaxane and beta-sheet layer-based three-dimensional coordination polymers constructed with silver salts and flexible pyridyl-type ligands Reviewed

    ML Tong, YM Wu, J Ru, XM Chen, HC Chang, S Kitagawa

    INORGANIC CHEMISTRY   41 ( 19 )   4846 - 4848   2002.9

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    A fascinating 3D pseudo-polyrotaxane architecture with 1D polymeric [Ag(bpp)](n) chains penetrating 2D (6,3) [Ag-2(bpp)(2)(ox)](n) sheets and a 3D coordination network constructed with 2D infinite [Ag(ppa)], beta-sheetlike layers pillared by ox ligands (bpp = 1,3-bis-(4-pyridyl)propane; ppa = N-(4-pyridinylmethyl)-4-pyridinecarboxamide; ox = oxalate) have been prepared by utilizing flexible pyridyl-type ligands and have been crystallographically characterized. Crystal data for 1: monoclinic, space group C2/c, a = 7.619(2) Angstrom, b = 19.781(4) Angstrom, c = 26.799(5) Angstrom, beta = 94.720(10)degrees, U = 4025.2(15) Angstrom(3), and Z = 4. Crystal data for 2: monoclinic, space group C2/c, a = 28.947(8) Angstrom, b = 8.617(3) Angstrom, c = 16.307(6) Angstrom, beta =121.07(l)degrees, U = 3484(2) Angstrom(3), and Z= 4.

    DOI: 10.1021/ic0256922

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  • Crystal structure and 2-D stacking network of [Cu(Hsal)(2) (py)(2)](n) Reviewed

    LG Zhu, GQ Cai, S Kitagawa, HC Chang

    CHINESE JOURNAL OF INORGANIC CHEMISTRY   18 ( 9 )   911 - 914   2002.9

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    The title complex, [Cu(Hsal) (2)(py)(2)], was synthesized by layered-solution technique and structurally characterized by single-crystal X-ray. The copper atom has a square pyramidal geometry and the coordination number is five. The molecular structure is linear one-dimensional network. There is a stacking effect between pyridine ligands of neighbouring 1-D chains and the molecular structure is extended into two-dimensional stacking network. Two salicylates in the complex have a position of crab pincers-like, in which one salicylate is unidentate and another coordinates through the carboxylate group and phenyl group unidentately.

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  • Synthesis and ligand-based mixed valency of cis- and trans-Cr-III(X(4)SQ)(X(4)Cat)(L)(n) (X = Cl and Br, n=1 or 2) complexes: Effects of solvent media on intramolecular charge distribution and ligand dissociation of Cr-III(X(4)SQ)(3) Reviewed

    HC Chang, K Mochizuki, S Kitagawa

    INORGANIC CHEMISTRY   41 ( 17 )   4444 - 4452   2002.8

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    The treatment of CrIII(X(4)SQ)(3) (SQ = o-semiquinonate; X = Cl and Br) with acetonitrile affords trans-Cr-III(X(4)SQ)- (X(4)Cat)(CH3CN)(2) (X = Cl (1) and Br (2)). In the presence of 2,2'-bipyridine (bpy) or 3,4,7,8-tetramethyl-1,10-phenanthrene (tmphen), the reaction affords Cr-III(X(4)SQ)(X(4)Cat)(bpy)(.)nCH(3)CN (X = Cl, n = 1 (3); X = Br, n = 0.5 (4)) or Cr-III(X(4)SQ)(X(4)Cat)(tmphen) (X = Cl (5) and Br (6)), respectively. All of the complexes show a ligand-based mixed-valence (LBMV) state with SQ and Cat ligands. The LBMV state was confirmed by the presence of the interligand intervalence charge-transfer band. Spectroscopic studies in several solvent media demonstrate that the ligand dissociation included in the conversion of Cr-III(X(4)SQ)(3) to 1-6 occurs only in solvents with relatively high polarity. On the basis of these results, the effects of solvent media were examined and an equilibrium, Cr-III(X(4)SQ)(3) Cr-III(X(4)BQ)(X(4)SQ)(X(4)Cat) (BQ = o-benzoquinone), is proposed by assuming an interligand electron transfer induced by solvent polarity.

    DOI: 10.1021/ic025643p

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  • Novel flexible frameworks of porous cobalt(III) coordination polymers that show selective guest adsorption based on the switching of hydrogen-bond pairs of amide groups Reviewed

    K Uemura, S Kitagawa, M Kondo, K Fukui, R Kitaura, HC Chang, T Mizutani

    CHEMISTRY-A EUROPEAN JOURNAL   8 ( 16 )   3586 - 3600   2002.8

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    Four porous crystalline coordination polymers with two-dimensional frameworks of a double-edged axe-shaped motif, {[Co(NCS)(2)(3-pia)(2)] . 2EtOH . 11 H(2)O}(n) (1a), {[Co(NCS)(2)- (3-pia)(2)] . 4Me(2)CO}(n) (3a), {[Co(NCS)(2)- (3-pia)(2)] . 4THF}(n) (3b) and {[Co(NCS)(2)- (3-pna)(2)](n)} (5), have been synthesized by the reaction of cobalt(ii) thiocyanate with N-(3-pyridyl)isonicotinamide (3-pia) or N-(3-pyridyl)nicotinamide (3-pna). X-ray crystallographic characterization reveals that adjacent layers are stacked such that channels are created, except in 5. The channels form a hydrogen-bonded interior for guest molecules; in practice, I a contains ethanol and water molecules as guests in the channels with hydrogen bonds, whereas 3b (3a) contains tetrahydrofuran (acetone) molecules. In la, the "double-edged axe-shaped" motifs in adjacent sheets are not located over the top of each other, while the motifs in 3b stack so perfectly as to overlap each other in an edge-to-edge fashion. This subtle change in the three-dimensional framework is associated with the template effect of the guests. Compound 5 has no guest molecules and, therefore, the amide groups in one sheet are used for hydrogen-bonding links with adjacent sheets. Removal of the guest molecules from la and 3b (3a) causes a structural conversion accompanied by a color change. Pink 1 a cannot retain its original framework and changes into a blue amorphous compound. On the other hand, the framework of pink 3b (3a) is transformed to a new crystalline framework of violet 4. Interestingly, 4 reverts to the original pink crystals of 3b (3a) when it is exposed to THF (or acetone) vapor. Spectroscopic measurements (visible, EPR, and IR) provide a clue to the crystal-to-crystal transformation; on removal of the guests, the amide groups are used to form the P sheet-type hydrogen bonding between the sheets, and thus the framework withstands significant stress on removal of guest molecules. This mechanism is attributed to the arrangement of the adjacent sheets so suited in regularity that the P sheet-type structure forms efficiently. The apohost 4 does not adsorb cyclopentane, showing a guest selectivity that, in addition to size, hydrogen-bonding capability is required for the guest molecules. The obtained compound is categorized as a member of a new generation of compounds tending towards functional porous coordination polymers.

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  • Syntheses and crystal structures of mononuclear rhodium hydrido complexes from the reactions of [Rh(H)(2)(PPh3)(2)(EtOH)(2)]ClO4 with various nitrogen ligands Reviewed

    XY Yu, M Maekawa, T Morita, HC Chang, S Kitagawa, GX Jin

    POLYHEDRON   21 ( 16 )   1613 - 1620   2002.7

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    Reactions of the Rh hydrido complex [Rh(H)(2)(PPh3)(2)(EtOH)(2)]ClO4 (1) With nitrogen ligands such as 2-(4-thiazolyl)benzimidazole (tbz). pyridazine (pdz), imidazole (im) and pyrimidine (pmd) in CH,Cl, afforded Various mononuclear Rh hydrido complexes, [Rh(H)(2)(PPh3)(2)(tbz)]CIO4 (2), [Rh(H)(2)(PPh3)(2)(pdZ)(2)]ClO(4)(.)2CH(2)Cl(2) (3). [Rh(H)Cl(PPh3)(2)(pdz)(2)](ClO4CH2Cl2)-C-. (4). [Rh(H)(2)(PPh3)(2)(im)(2)]ClO(4)(.)2CH(2)Cl(2) (5). [Rh(H)Cl(PPh3)(2)(im)(2)](ClO4CH2Cl2)-C-. (6). [Rh(H)(2)(PPh3)(2)(pmd)(2)](ClO4CH2Cl2)-C-. (7) and the Rh non-hydrido complex [RhCl2(pmd)(4)]ClO4 (8). The Rh complexes 2. 3, 5 and 6 were crystallographically characterized. The formation process was monitored by H-1 NMR and UV-Vis spectra. In all the Rh hydrido complexes, the Rh atom is coordinated by two PPh3. ligands in trans-positions and two nitrogen ligands in the cis-positions. The remaining sites Lire occupied by one or two hydride atoms to form a saturated 18-electron framework in a slightly distorted octahedral geometry. For complex 2 an appreciable inter-molecular pi interaction is observed between planes of tbz and PPh3 ligands, while an intra-molecular hydrogen bonding interaction between C-H and Cl atoms is found in complex 6. (C) 2002 Elsevier science Ltd. All rights reserved.

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  • Out-of-Plane Dimers of Mn(III) Quadridentate Schiff-Base Complexes with Saltmen2- and Naphtmen2- Ligands: Structure Analysis and Ferromagnetic Exchange Reviewed

    H. Miyasaka

    J. Chem. Soc. Dalton Trans.   ( 7 )   1528 - 1534   2002.4

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  • Solvent-dependent formation of di- and trinuclear rhodiurn and iridium complexes bridged by N,N '-donor ligands Reviewed

    XY Yu, M Maekawa, T Morita, HC Chang, S Kitagawa, GX Jin

    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN   75 ( 2 )   267 - 275   2002.2

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    Reactions of Rh and Ir hydrido complexes. [Rh(H)(2)(PPh3)(2)(solv)(EtOH)]ClO4 (solv = Me2CO, 1a; EtOH, 1b) and [Ir(H)(2)(PPh3)(2)(Me2CO)(2)]BF4 (2), with various N,N'-donor bridging ligands, such as pyrazine (pyz), 4,4'-trimethylenedipyridine (tmdp) and di(4-pyridyl) disulfide (dpds), in some solvents were examined, and their reaction products were characterized by X-ray crystal structure analysis. IR, H-1 NMR and UV-vis spectra. Rh hydrido complexes, la or 1b, formed a dinuclear Rh complex, [Rh-2(PPh3)(2) {(eta(6)-C6H5PPh2}(2)] (ClO4)(2).6CH(2)Cl(2) (3.6CH(2)Cl(2)), in dichloromethane with a reductive elimination of hydrogen. The reactions of 1a or 1b with the pyz ligand in dichloromethane and tetrahydrofuran gave triangular Rh-3 complexes, [Rh-3(PPh3)(6)(pyz)(3)](ClO4)(3).CH2Cl2 (5.CH2Cl2) and [Rh-3(PPh3)(6)(pyz)(3)](ClO4)(3).EtOH (5.EtOH), respectively, in contrast to the formation of a dinuclear Rh hydrido complex, [Rh-2(H)(4)(PPh3)(4)(Me2CO)(2)(pyz)](ClO4)(2).EtOH A-EtOH). in acetone. The reactions of la or 1b with the tmdp ligand in dichloromethane and 3-methyl-2-butanone also afforded dinuclear Rh complexes, [Rh-2(PPh3)(4)(tmdp)(2)](ClO4)(2) (6) and [Rh-2(PPh3)(4)(tmdp)(2)](ClO4)(2).4MeCOCHMe(2) (6.4MeCOCHMe(2)), respectively. On the other hand, Ir hydrido complex 2 reacted with pyz and dpds ligands in dichloromethane to afford dinuclear Ir complexes, [Ir-2(H)(4)(PPh3)(4)(Me2CO)(2)(pyz)]- (BF4)(2).3CH(2)Cl(2) (7.3CH(2)Cl(2)) and [Ir-2(H)(4)(PPh3)(4)(dpds)(2)](BF4)(2).3CH(2)Cl(2).H2O (8.3CH(2)Cl(2).H2O), respectively, without any reductive elimination of hydrogen. Based on structural studies in solution and in the solid state. it was demonstrated that various Rh and Ir complexes were selectively produced depending on the choice of solvents and N,N'-donor bridging ligands.

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  • New one-dimensional chain compounds of [M (pdz) Cl-2](n)(M=Cu(II), Fe(II), Mn(II); pdz = pyridazine and their magnetic properties Reviewed

    T Yi, HC Chang, S Kitagawa

    MOLECULAR CRYSTALS AND LIQUID CRYSTALS   376 ( 376 )   283 - 288   2002

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    Three novel one-diniensional coordination polymers with pyridazine (pdz), [M (pdz) Cl-2]n (M = Cu (II) (1), Fe (II) (2), Mn (II) (3)), were synthesized and characterized. All the compounds have one-dimensional zigzag chain structures. The copper ion in compound 1 has a planer coordination sphere with two bridging pdz ligands and two Cl-anions, while the metal ions in the other compounds have a distorted octahedral environment with pdz and Cl- groups both acting as bridges. The magnetic data of these compounds show antiferromagnetic interaction between the magnetic centers within the chains.

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  • An unprecedented mixed-charged state in a supramolecular assembly of ligand-based mixed-valence redox isomers (ET center dot+)(3)[Cr-III-(Cl(4)SQ)(2)(Cl(4)Cat)](-)[Cr-III(Cl(4)SQ)(Cl(4)Cat)(2)](2-) Reviewed

    HC Chang, S Kitagawa

    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION   41 ( 1 )   130 - 133   2002

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  • X-ray crystal structures and two-dimensional pi ... pi stacking interaction of Cr-III(X(4)SQ)(3) center dot 4C(6)H(6) (X=Cl and Br) Reviewed

    HC Chang, Susumukitagawa

    MOLECULAR CRYSTALS AND LIQUID CRYSTALS   376 ( 376 )   275 - 282   2002

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    Tris(tetrahalogeno-o-semiquinonate) chromium (III) complexes, Cr-III(Cl(4)SQ)(3).4C(6)H(6) (1) and Cr-III(Br(4)SQ)(3).4C(6)H(6) (2), crystallize in an isostructural form; tetragonal, P4(1)2(1)2 with a = 13.452(2) Angstrom, c = 24.78(2) Angstrom, V = 4484(3) Angstrom(3) and a = 13.7465(7) Angstrom, c = 25.680(1) Angstrom, V = 4852.6(4) Angstrom(3) for 1 and 2, respectively. The inner coordination environments of the complex molecules are similar to that of previously reported crystal, Cr-III(Cl(4)SQ)(3).CS2.1/2C(6)H(6), while both complexes show strong pi...pi interaction between the three SQ ligands and the four solvate benzene molecules, resulting the formation of two-dimensional pi...pi stacking array. The effect of pi...pi interactions was evaluated by thermogravimetric and differential scanning calorimetric analysis where the weigh loss corresponding to the four benzene molecules was observed up to 500 K indicative of the interactions between the ligands and solvated benzene molecules.

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  • Syntheses, structures, and physicochemical properties of diruthenium compounds of tetrachlorocatecholate with metal-metal bonded Ru3+(mu-OR)(2)Ru3+ and Ru3.5+(mu-OR)(2)Ru3.5+ cores (R = CH3 and C2H5) Reviewed

    H Miyasaka, HC Chang, K Mochizuki, S Kitagawa

    INORGANIC CHEMISTRY   40 ( 14 )   3544 - 3554   2001.7

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    Metal-metal bonded Ru3+(mu -OR)(2)Ru3+ and Ru3.5+(mu -OR)(2)Ru3.5+ (R = CH3 and CH3CH2) compounds with tetrachlorocatecholate (Cl(4)Cat) have been synthesized in the corresponding alcohol, MeOH and EtOH, from a nonbridged Ru2+-Ru3+ compound, Na-3[Ru-2(Cl(4)Cat)(4)(THF)]. 3H(2)O . 7THF (1). In alcohol solvents, compound 1 is continuously oxidized by oxygen to form Ru3+(mu -OR)(2)Ru3+ and Ru3.5+(mu -OR)(2)Ru3.5+ species. The presence of a characteristic countercation leads to selective isolation of either Ru3+(mu -OR)(2)Ru3+ or Ru3.5+(mu -OR)(2)Ru3.5+ as a stable adduct species. In methanol, Ph4PCl and dibenzo-18-crown-6-ether afford Ru3+(mu -OMe)(2)Ru3+ species, [A](2)[Ru-2(Cl(4)Cat)(4)(mu -OMe)(2)Na-2(MeOH)(6)] ([A](+) = Ph4P+ (2), [Na(dibenzo-18-crown-6)(H2O)(MeOH)](+) (3)), while benzo-15-crown-5-ether provides a Ru3.5+(mu -OMe)(2)Ru3.5+ species, [Na(benzo-15-crown-5)(2)][Ru-2(Cl(4)Cat)(4)(mu -OMe)(2)Na-2(MeOH)(6)] (4). The air oxidation of 1 in a MeOH/EtOH mixed solvent (1:1 v/v) containing benzo-15-crown-5-ether provides a Ru3.5+(mu -OMe)(2)Ru3.5+ species, [Na(benzo-15-crown-5)(H2O)][Ru-2(Cl(4)Cat)(2)(mu -OMe)(2)Na-2-(EtOH)(2)(H2O)(2)(MeOH)(2)](.)(benzo-15-crown-5) (5). Similarly, the oxidation of 1 in ethanol with Ph4PCl provides a Ru3.5+(mu -OEt)(2)Ru3.5+ species, (Ph4P)[Ru-2(Cl(4)Cat)(4)(mu -OEt)(2)Na-2(EtOH)(6)] (7). A selective formation of a Ru3+(mu -Oet)(2)Ru3+ species, (Ph4P)(2)[Ru-2(Cl(4)Cat)(4)(mu -OEt)(2)Na-2(EtOH)(2)(H2O2)(2)] (6), is found in the presence of pyrazine or 2,5-dimethylpyrazine. The crystal structures of these compounds, except 2 and 7, have been determined by X-ray crystallography, and all compounds have been characterized by several spectroscopic and magnetic investigations. The longer Ru-Ru bonds are found in the Ru3+(mu -OR)(2)Ru3+ species (2.606(1) and 2.628(2) Angstrom for 3 and 6, respectively) compared with those of Ru3.5+(mu -OMe)(2)Ru3.5+ species (2.5260(6) Angstrom and 2.514(2) Angstrom for 4 and 5, respectively.
    These structural features and magnetic and ESR data revealed the electronic configurations of sigma (2)pi (2)delta (*2)delta (2)pi (*2) and sigma (2)pi (2)delta (*2)delta (2)pi (*1) for Ru3+(mu -OR)(2)Ru3.5+(mu -OR)(2)Ru3.5+, respectively, in which the former is diamagnetic and the latter is paramagnetic with S = 1/2 ground state. Compound 5 forms a one-dimensional chain with alternating arrangement of a Ru3.5+(mu -OMe)(2)Ru3.5+ unit and a free benzo-15-crown-5-ether molecule by intermolecular hydrogen bonds (O(H2O). . .O(crown-ether) = 2.91-3.04 Angstrom).
    The cyclic voltammetry in DMF affords characteristic metal-origin voltammograms; two quasi-reversible redox waves were observed. The feature of cyclic voltammograms for the Ru3+(mu -OR)(2)Ru3+ species (2,3, and 6) and the Ru3.5+(mu -OR)(2)Ru3.5+ species (4 and 7) are similar to each other, indicating that both species are electrochemically stable. The isolation of the pyrazine-trans-coordinated species, [Ph4P][Ru(Cl(4)Cat)(2)(L)(2)] (L = pyrazine (8), 2,5-dimethylpyrazine (9)), revealed the selective isolation of 6 from pyrazine-containing solution. UV-vis spectral variation by ethanolysis for 9 demonstrated the selective conversion from the pyrazine-trans-coordinated species to the Ru3+(mu -OEt)(2)Ru3+ species without an oxidation to the Ru3.5+(mu -OEt)(2)Ru3.5+ species. This result suggests the presence of equilibrium between [Ru(Cl(4)Cat)(2)(L)(2)](-) and Ru3+(mu -OEt)(2)Ru3+ species in the synthetic condition for 6.

    DOI: 10.1021/ic0010252

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  • New molecular assemblies of redox isomers, [Cr-III(X(4)SQ)(3-n)(X(4)Cat)(n)](-n) (X = Cl and Br; n=0, 1, and 2), with metallocenium cations, [(MCp2)-Cp-III](+) (M = Co and Fe): X-ray crystal structures and physical properties Reviewed

    HC Chang, H Miyasaka, S Kitagawa

    INORGANIC CHEMISTRY   40 ( 1 )   146 - 156   2001.1

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    A series of redox isomers of [Cr-III(X(4)SQ)(X(4)Cat)(2)](2-) , [Cr-III(X(4)SQ)(2)(X(4)Cat)](-), and [Cr-III(X(4)SQ)(3)](0) (X = Cl and Sr, SQ = semiquinonate, and Cat = catecholate) have been synthesized and characterized as charge-transfer (CT) compounds with metallocenium cations: ((CoCP2)-C-III)(2)[Cr-III(Cl(4)SQ)(Cl(4)Cat)(2)] (1), ((CoCp2)-Cp-III)(2)[Cr-III(Br(4)SQ)(Br(4)Cat)(2)] (2), ((FeCp2)-Cp-III) [Cr-III(Cl(4)SQ)(2)(Cl(4)Cat)].C6H6 (4), ((FeCp2)-Cp-III) [Cr-III(Br(4)SQ)(2)(Br(4)Cat)]. CS2 (5), and ((FeCp2)-Cp-III)[Cr-III(Cl(4)SQ)(2)(Cl(4)Cat)][Cr-III(Cl(4)SQ)(3)] (6). First, the oxidation states of the chromium complexes are strongly dependent on the redox potentials of the metallocenes used. The (CoCp2)-Cp-II, exhibiting stronger reduction power than (FeCp2)-Cp-II, is useful for two-electron reduction of the [Cr-III(X(4)SQ)(3)](0), affording [Cr-III(X4SQ) (X(4)Cat)(2)](2-) (1 and 2), which are first isolated and crystallographically characterized in the solid state. In contrast the reaction with (FeCp2)-Cp-II affords only [Cr-III(X(4)SQ)(2)(X(4)Cat)](-) (4 and 5). Second, solvents influence crystal structures of these compounds. The solvent set of C6H6/CS2 gives 1:1:C6H6 compound 4 with unique charged anions, [Cr-III(C(4)SQ)(2)(Cl(4)Cat)](-), while the other set, n-C6H12/CS2, affords 1:2 compound 6 including the two redox isomers, [Cr-III(Cl(4)SQ)(2)(Cl(4)Cat)](-) and [Cr-III(Cl(4)SQ)(3)](0). The [Cr-III(X(4)SQ)(X(4)Cat)(2)](2-) anions in 1 and 2 show no significant interconnection between them (discrete type), while the [Cr-III(X(4)SQ)(2)(X(4)Cat)](-) anions in 4-6 show one- dimensional column-type structures with the aid of intermolecular stacking interactions of the ligand moieties. The anions in 4 show additional stacking interaction with the [(FeCp2)-Cp-III](+) to form one-dimensional ...[D][A][S][D][A]...(D = [(FeCp2)-Cp-III](+), A = [Cr-III(Cl(4)SQ)(2)(Cl(4)Cat)](-), and S = C6H6) type mixed-stack arrangements similar to that of previously reported ((CoCp2)-Cp-III)[Cr-III(Cl(4)SQ)(2)(Cl(4)Cat)].C6H6 (3) Compound 6 forms a two-dimensional sheet structure where the two redox isomers, [Cr-III(Cl(4)SQ)(2)(Cl(4)Cat)](-) and [Cr-III(Cl(4)SQ)(3)](0), are included. The sheet is regarded as a mixed-valence molecular assembly.
    Two types of the anions, [Cr-III(X(4)SQ)(X(4)Cat)(2)](2-) (1 and 2) and [Cr-III(X(4)SQ)(2)(X(4)Cat)](-) (4-6), exhibiting an intramolecular mixed-valence state, show intramolecular intervalence CT transition (IVCT) from the Cat to the SQ at near 5800 and 4300 cm(-1), respectively, both in the solution and in the solid states. The intermolecular mixed- valence state of 6 was characterized by absorption spectroscopy, electric conductivity, and SQUID magnetometry. Interestingly, this mixed-valence state of the chromium module is dependent on the redox active nature of the coordinated ligands.

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  • A New Class of Cyclic Hexamer: [Co6L6](24-) (H6L = hexaazatriphenylene hexacarboxylic acid) Reviewed

    S Masaoka, S Furukawa, HC Chang, T Mizutani, S Kitagawa

    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION   40 ( 20 )   3817 - +   2001

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  • Hydrogen-bond network of dimeric copper complex of vanillic acid (HVA), [Cu(VA)(2)(H2O)](2) Reviewed

    LG Zhu, S Kitagawa, HC Chang, H Miyasaka

    MOLECULAR CRYSTALS AND LIQUID CRYSTALS   342 ( 97-102 )   97 - 102   2000

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    The crystal structure of the title complex was first determined, showing a dimeric copper form with the four carboxylate groups. The Cu ... Cu distance is short, associated with the hydrogen bond link of the apically coordinated water molecules with the nearest neighbor vanillic hydroxyl group. The hydrogen bond links afford an infinite 3-D network.

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  • Synthesis, X-ray crystal structures and properties of chromium complexes with semiquinonate and catecholate Reviewed

    HC Chang, T Ishii, M Kondo, S Kitagawa

    JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS   ( 15 )   2467 - 2476   1999.8

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    The reaction of tris-tetrahalogeno-o-benzosemiquinonate chromium(III) complexes, [Cr-III(X(4)SQ)(3)] (X=Cl 1a or Br 1b), with bis(cyclopentadienyl) cobalt [(CoCp2)-Cp-II], tetramethyltetraselenafulvalene (TMTSF) and tetrakis(methylsulfanyl)tetrathiafulvalene (TMT-TTF) afforded four charge-transfer compounds, [(CoCp2)-Cp-III][Cr-III(X(4)SQ)(2)(X(4)Cat)] (X=Cl 2a or Br 2b), [TMT-TTF][Cr-III(Br(4)SQ)(2)(Br(4)Cat)] 3b and [TMTSF][Cr-III(Br(4)SQ)(2)(Br(4)Cat)] 4b, where Cat is catecholate. The paramagnetic [Cr-III(X(4)SQ)(2)(X(4)Cat)](-) complexes are commonly formed by cocrystallization with a diamagnetic [(CoCp2)-Cp-III](+) cation for 2a . C6H6 and 2b, and paramagnetic TMT-TTF.+ and TMTSF.+ cations for 3b . C6H5CH3 and 4b . 2CH(2)Cl(2), respectively. The one-electron reduced complexes, [Cr-III(X(4)SQ)(2)(X(4)Cat)](-), with two semiquinonate and one catecholate ligands were isolated and crystallographically characterized. The crystal structures of 2a . C6H6 and 3b . C6H5CH3 consist of alternating stacks of cations and anionic complexes, which form one-dimensional column structures. On the other hand, the anionic complexes in 4b . 2CH(2)Cl(2) form a hexagonal honeycomb network, whose cavities are occupied by the dimerized cation molecules. The temperature dependence of the magnetic susceptibilities reveals that all the [Cr-III(X(4)SQ)(2)(X(4)Cat)](-) complexes are in a ground state of S=1/2, which results from the intramolecular antiferromagnetic interaction between Cr-III(d(3)) and two semiquinonates. In addition, 3b and 4b have a contribution of the paramagnetic TMT-TTF.+ (3b) and TMTSF.+ (4b) cations. In all compounds weak intermolecular magnetic interactions were recognized from the decrease of the chi(m)T values at low temperature.

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  • New Coordination Networks Constructed from N-(4-pyridyl)isonicotinamide Reviewed

    M. Kondo, A. Asami, H.-C. Chang, S. Kitagawa

    Cryst. Eng.   2 ( 2 )   115 - 122   1999.6

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Elsevier  

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  • Structural, spectroscopic and magnetic properties of charge-transfercomplex, (TMTSF) [Cr(Cl(4)SQ)(2)(Cl(4)Cat)]center dot 0.5CH(2)Cl(2) Reviewed

    HC Chang, S Kitagawa, M Kondo, T Ishii

    MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS   335   895 - 904   1999

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    A complex (TMTSF)[Cr(Cl(4)SQ)(2)(Cl(4)Cat)](1). 0.5CH(2)Cl(2) (SQ = semiquinonate; Cat = cate-cholate, TMTSF = tetramethyltetraselenafulvalene) has been synthesized and characterized. 1 . 0.5CH(2)Cl(2) crystallizes in the monoclinic, space group P2(1)/n with a = 12.472(3) A, b = 17.451(4) Angstrom, c = 18.815(5) Angstrom, beta = 101.80(2)degrees and V=4008(1) Angstrom(3). 1 . 0.5CH(2)Cl(2) contains a paramagnetic TMTSF+ cation and an unprecedented anion [Cr(Cl(4)SQ)(2)(ClCat)](-) as a result of one-electron redox reaction between TMTSF and Cr(Cl(4)SQ)(3). Structure of 1 . 0.5CH(2)Cl(2) consists of dimerized TMTSF+ cation, (TMTSF+)(2) and one dimensionally stacked [Cr(Cl(4)SQ)(2)(Cl(4)Cat)(-) anions. 1 behaves as a semiconductor, and its magnetic susceptibility obeys a Curie-Weiss law in the region of 150-300 K.

    Web of Science

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  • Structural, Spectroscopic and Magnetic Properties of Charge-Transfer Complex, (TMTSF)[Cr(Cl4SQ)2 (Cl4Cat)]•0.5CH2Cl2 Reviewed

    H.-C. Chang, S. Kitagawa, M. Kondo, T. Ishii

    Mol. Cryst. Liq. Cryst.   335   183 - 192   1999

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Books

  • Inorganic Chromotropism-Basic Concepts and Applications of Colored Materials

    S. Kitagawa, H.-C. Chang( Role: Joint authorChapter 8, 8.1, 337-354|rn|Ligand-based Redox-active Complexes for Electrochromic Materials)

    SPRINGER,講談社/福田豊・編  2007.5 

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  • 丸善株式会社実験化学講座第5版

    張 浩徹, 北川 進( Role: Joint author22巻, 4章,4-3|rn|原子価揺動錯体(バレンストートメリズム))

    丸善株式会社/日本化学会 編  2004.7 

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  • Synthesis, Structures, and Physico-Chemical Properties of Diruthenium Compounds of Tetrachloro-o-catecholate with Ru3+(m-OR)2Ru3+ and Ru3.5+(m-OR)2Ru3.5+ Cores (R = CH3, and C2H5)

    2001 

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  • A New Class of Cyclic Hexamer: [Co6L6]24- (H6L = hexaazatriphenylene hexacarboxylic acid)

    Angew. Chem. Int. Ed. Engl  2001 

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  • New Molecular Assemblies of Redox Isomers, [CrIII(X4SQ)3–n(X4Cat)n]–n (X = Cl, Br, n = 0, 1, and 2) with Metallocenium Cations, [MIIICp2]+ (M = Co and Fe), X-ray Crystal Structures and Physical Properties

    2001 

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  • Hydrogen-Bond Network of Dimeric Copper Complex of Vanillic Acid (HVA), [Cu(VA)2(H2O)]2

    2000 

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  • Synthesis, X-ray Crystallographic Structures and Properties of Chromium Complexes with Semiquinonate and Catecholate

    J. Chem. Soc. Dalton Trans  1999 

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  • New Coordination Networks Constructed from N-(4-pyridyl)isonicotinamide

    Cryst. Eng.  1999 

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  • Structural, Spectroscopic, and Magnetic Properties of Charge-transfer complex (TMTSF)[Cr(Cl4SQ)2(Cl4Cat)]0.5CH2Cl2 H.Chang, S.Kitagawa, M.Kondo, and T.Ishii

    Mol. Cryst. Liq. Cryst.  1999 

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MISC

  • o‐フェニレンジアミン3d金属錯体が示す光水素発生反応

    張浩徹, 松本剛, 上野導, 中山哲, 武次徹也, 小林厚志, 加藤昌子

    配位化合物の光化学討論会講演要旨集   24th   41 - 42   2012.8

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    J-GLOBAL

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  • PB33 Flexible Electronic Structures and Assembled Structures of Redox-active Metal Complexes

    CHANG Ho-Chol, KIRIYA Daisuke, SHIOZAKI Tomoki, OHMORI Takashi, KITAGAWA Susumu

    ( 2005 )   355 - 356   2005.9

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    Language:Japanese   Publisher:Japanese Liquid Crystal Society  

    CiNii Books

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  • PB08 Structural Control and Properties of Metal Complexes with Redox-active Polycatecholates

    CHANG Ho-Chol, SHIOZAKI Tomoki, FURUKAWA Hirotaka, YAMAUCHI Takae, KIRIYA Daisuke, KAMATA Akiko, KITAGAWA Susumu

    日本液晶学会討論会講演予稿集   ( 2004 )   344 - 345   2004.9

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    Novel mono/trinuclear palladium/platinum complexes and valence tautomeric Co complexes with alkyl chains have been characterized by X-ray diffraction, electrochemical, and thermogravimetric analyses. All the complexes possess catecholate derivatives, which have been known to show rich redox activity or bistability derived from the intramolecular electron transfer process. The results obtained in this study clearly suggest that the complexes would be candidates for redox-active metallomesogens.

    DOI: 10.11538/ekitou.2004.0.171.0

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  • Cover Picture: Angewandte Chemie International Edition 43(25) 2004年 Invited

    Tapas Kumar Maji, Kazuhiro Uemura, Ho-Chol Chang, Ryotaro Matsuda, Susumu Kitagawa

    Angewandte Chemie International Edition   43 ( 25 )   3205 - 3205   2004.6

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    Publisher:Wiley  

    DOI: 10.1002/anie.200490079

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  • 配位結合がつくる自己集合、自己組織化の世界

    北川進, 張 浩徹

    現代化学   24 - 30   2003.3

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Presentations

  • Molecular and Macroscopic Transformation of Assembled Metal Complexes by Electron Transfers

    Ho-Chol Chang

    International Conference on Coordination Chemistry 40  2012.9 

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  • σ-フェニレンジアミン3d金属錯体が示す光水素発生反応

    第24回配位化合物の光化学討論会  2012.8 

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  • Chemical Melting by Electron Transfer

    Ho-Chol Chang

    9th Japan-China Joint Symposium on Metal Cluster Compounds  2012.8 

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  • Chemical Melting by Electron Transfers

    Ho-Chol Chang

    8th International Workshop on Supramolecular Nanoscience of Chemically Programmed Pigments  2012.6 

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  • Molecular and Macroscopic Transformation Triggered by Electron Transfer

    Ho-Chol Chang

    Canada-Japan Joint Symposium on Supramolecular Nanomaterials Science  2012.5 

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  • Molecular and Macroscopic Transformation Triggered by Electron Transfer

    Ho-Chol Chang

    12th Eurasia Conference on Chemical Sciences  2012.4 

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  • ノンイノセント型配位子を含む錯体集合体の外場応答性

    Innovationを目指す若手錯体科学者シンポジウム  2012.3 

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  • 外場誘起電子移動による分子とマクロ相の動的変換

    光応答性分子による機能性材料および界面構築に関する講演会  2011.12 

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  • Non-Innocentな錯体化学

    錯体化学若手の会夏の学校2012  2011.7 

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  • Synchronicity in Molecular and Macroscopic Bistability

    Ho-Chol Chang

    France-Japan Coordination Chemistry Symposium 2011  2011.6 

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  • Synchronic transformation of molecular states and macroscopic phases

    分子研研究会「金属錯体の機能化の現状と将来展望」  2011.1 

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  • Redox-active Metallomesogens: Fluctuated structures and electrochemical bistability

    Ho-Chol Chang

    PACIFICHEM 2010  2010.12 

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  • Synchronicity in Molecular and Macroscopic Bistability

    Ho-Chol Chang

    PACIFICHEM 2010  2010.12 

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  • Synchronicity in Molecular and Macroscopic Bistability

    Ho-Chol Chang

    The 1st International Symposium on Advanced Soft Materials  2010.11 

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  • Redox-active Metallomesogens

    Ho-Chol Chang

    Mini-symposium on Metallomesogens  2010.10 

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  • Synchronicity in Valence Tautomeric Bistability and Macroscopic Phase Transitions

    Ho-Chol Chang

    11th Eurasia Conference on Chemical Sciences  2010.10 

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  • Synchronicity in Valence Tautomeric Bistability and Macroscopic Phase Transitions

    Ho-Chol Chang

    8th China-Japan Joint Symposium on Metal Cluster Compounds  2010.8 

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  • 金属錯体液晶が示す揺動構造とレドックス双安定性

    日本化学会春季年会シンポジウム動的金属錯体の機能制御-価数制御と電子移動-  2010.3 

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  • レドックス活性双安定液晶の創成

    新学術領域研究—配位プログラミング第一回公開シンポジウム  2010.1 

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  • 電子が操るミクロ分子とマクロ世界のシンクロニシティー

    第59回錯体化学討論会シンポジウム「ソフトマターとしての金属錯体」Symposium  2009.9 

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  • Synchronic Transformation of Molecular States and Macroscopic Phases Triggered by Electron Transfer Processes

    Ho-Chol Chang

    The 3rd GCOE International Symposium, Hokkaido University Global COE Program  2009.9 

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  • Molecular Bistability Synchronized with Macroscopic Transition

    Ho-Chol Chang

    JSPS Asian CORE Program China-Japan Joint Symposium on Functional Supramolecular Architectures  2009.8 

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  • Synchronicity in Macroscopic Transformation and Electron Transfer Processes at Molecular Scale

    Ho-Chol Chang

    Asian International Symposium-Coordination and Organometallic Chemistry  2009.3 

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  • Macroscopic Phase Transformation Synchronized with Electron Transfers at Molecule

    Ho-Chol Chang

    Second Japan-Russia Joint Symposium on Chiral Porous Coordination Polymers for Separation and Catalysis  2009.2 

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  • 電子で繋ぐ分子とマクロ世界

    第2回研究会「金属錯体の固体物性科学最前線—錯体化学と固体物性物理の新奇融合領域創成をめざして」  2008.12 

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  • Stimuli-sensitive Dinuclear Ruthenium Complex with Redox-active Catecholates

    Ho-Chol Chang

    7th China-Japan Joint Symposium on Metal Cluster Compounds  2008.10 

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  • 液晶場におけるレドックス化学

    第58回錯体化学討論会シンポジウム「レドックス金属錯体が拓く未来科学」  2008.9 

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  • Synchronicity in Macroscopic Transformation and Electron Transfer Processes at Molecular Scale

    Ho-Chol Chang

    Asian International Symposium-Coordination and Organometallic Chemistry  2008.3 

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  • Redox-active Metallomesogens

    Ho-Chol Chang

    Mini-symposium on Metallomesogens  2007.10 

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  • Redox-active Molecular Assemblies in Solid, Liquid, and Liquid Crystals

    Ho-Chol Chang

    The 1st Brain Korea 21 International Symposium and Workshop on Material Chemistry-2006  2006.11 

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  • Redox-active Molecular Assembly within Solid, Liquid, and Liquid Crystal

    Ho-Chol Chang

    First International Symposium on Chemistry of Coordination Space -ISCCS 2005-  2005.11 

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  • レドックス活性金属錯体を用いた分子集団の動的制御と機能

    研究会「光エネルギーと物質変換:光合成・光触媒・太陽電池および関連化学の革新」  2004.11 

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  • Structural and Physicochemical Controls of Ligand-unsupported Diruthenium Complexes |rn|with Catecholates

    Ho-Chol Chang

    5th China-Japan Joint Symposium on Metal Cluster Compounds  2004.7 

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  • レドックス活性配位子を利用した機能性錯体集合体の構築

    分子研研究会「錯体分子でなにができるか」  2004.3 

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  • Ligand-Base Mixed-Valence Supramolecular Assemblies

    Ho-Chol Chang

    Gordon Research Conferences, Organic Structures & Properties  2002.7 

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  • 酸化還元活性オルトキノン型配位子を用いた双安定性錯体素子の創製

    特定領域「集積型金属錯体」若手講演会  2002.2 

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  • Synthesis and Characterization of Direct Ru–Ru Bond Systems by use of Catecholate Derivatives

    4th China-Japan Joint Symposium on Metal Cluster Compounds  2001.10 

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  • セミキノネート(SQ)/カテコラート(Cat)混合原子価型配位子を有する分子性金属錯体集合体の合成とその性質

    錯体化学若手の会近畿支部勉強会  2000.12 

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Awards

  • 日本化学会北海道支部奨励賞

    2013.1   日本化学会北海道支部   ノンイノセント型分子の外場応答性に基づく化学機能の創出

  • 平成20年度錯体化学会研究奨励賞

    2008.9   錯体化学会   Assembled Functional Chemistry of Redox-active Complexes

  • 日本化学会第86春季年会優秀講演賞

    2006.5   日本化学会   レドックス活性金属錯体の液晶化と構造化学的相制御

  • 財団法人金萬有科学振興会第24回科学技術奨励賞

    2001.5   財団法人金萬有科学振興会   双安定性を有する錯体集合体の合成と新規物性

Research Projects

  • Emergent Functional Chemistry Based on External-Field-Adaptive Molecular Lattices

    Grant number:23H01978  2023.4 - 2026.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)  Chuo University

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    Grant amount: \18980000 ( Direct Cost: \14600000 、 Indirect Cost: \4380000 )

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  • 光駆動型ハイドライドの精密設計

    Grant number:19H02736  2019.4 - 2023.3

    日本学術振興会  科学研究費助成事業  基盤研究(B)  中央大学

    張 浩徹, 中田 明伸

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    Grant amount: \17420000 ( Direct Cost: \13400000 、 Indirect Cost: \4020000 )

    本研究では、申請者らが見出した非貴金属とH+及びe-を貯蔵できるπ系ジアミン配位子を含む錯体分子(Metal-binding π-diamine (MπA))を用いた光駆動型水素吸蔵・放出システムの学理を確立し、室温で光により駆動する光駆動型ハイドライドの確立を目指している。これまでの研究により本光駆動型ハイドライドの実現に向けた鍵反応である溶液中での励起状態水素脱離(ESHD)に基づいた光水素分子発生やアルコールの脱水素、また二酸化炭素の固定化や効率的な光ジスルフィド反応等の独創的な成果を見いだしてきた。一方これまでの反応系は溶液系であるために、溶媒との反応や副反応の抑制に課題を残している。さらに、水素重量密度を向上させる観点からも本材料の固体化が望まれる。そこで昨年度は、光水素貯蔵材料の固体化を目的とし、1,2,4,5-Benzenetetramine (BTA)を水素貯蔵部位及びESHD活性部位として用いた配位高分子において興味深い光電気化学挙動を見いだした。既報を参考に(Ni-BTA)nを修飾したITO電極は、モデル錯体であるNi(s-bqdi)2錯体と類似した890 nmに極大を有する吸収帯およびNH振動に特徴的なIR吸収を3300 cm-1に示した。また、この修飾電極は固体状態において配位子ベースの酸化及び還元に由来する電気化学応答を固体状態で示し、電気化学的に活性な物質であることが確認された。更に興味深い事に、-1 Vの定電位印加下において可視光を照射したところ、光カソード電流が増大し照射のON/OFFによりその応答が変調することも確認した。以上の結果は、電気化学的に電極上に形成した還元型高分子が光化学的に水素種・電子を放出することを期待させる。以上の知見は、高分子化した光水素脱離活性ユニットからの光水素脱離の可能性を示す興味深い結果である。

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  • Creation of novel reaction processes by precise control of highly active hydrogen

    Grant number:18H05517  2018.6 - 2023.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)  Kyushu University

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    Grant amount: \202540000 ( Direct Cost: \155800000 、 Indirect Cost: \46740000 )

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  • レドックス活性キラル錯体集合体の電気化学的異方性変換

    2019.4 - 2021.3

    日本学術振興会  新学術領域研究(研究領域提案型) 

    張 浩徹

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    Grant amount: \4940000 ( Direct Cost: \3800000 、 Indirect Cost: \1140000 )

    本研究「レドックス活性キラル錯体集合体の電気化学的異方性変換」では、レドックス活性な有機配位子を含むキラル錯体分子が集積化した結晶・液晶・液体を構築する。その目的は、凝集相に対する直接電気化学的レドックスを誘発することで、分子機能(電荷・スピン・不斉等)と集合相が階層的に連動する分子系を構築することにある。分子レベルにおける不斉種・不斉の強度・不斉の有無を集合相の異方性・次元性と結合させると共に、それをレドックスにより精密に変換・制御することで、自然界の対称性の破れを検証しうる配位アシンメトリーの学理を確立し、電気化学駆動制御型の光-電気-機能変換プラットホームを構築する。

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  • Photochemical dehydration of methanol by single-site-catalyst derived from redox-active metal complex

    Grant number:18K19101  2018.6 - 2020.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Challenging Research (Exploratory)  Chuo University

    Chand Ho-Chol

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    Grant amount: \6240000 ( Direct Cost: \4800000 、 Indirect Cost: \1440000 )

    In this work, we quantitatively revealed the relation between photochemical dehydration activity of MeOH via aminophenolato metal complexes and their co-ligands. We found that the complexation of M/apH unit with co-ligand depend on the nature of M and co-ligand. In particular, the activity increases up to 3.9 times when M = Fe with tBuCN as co-ligand with strong sigma-donation ability. These results would contribute towards the construction of single-site dehydration catalysis based on transition metal complexes with ligands with electron/proton pooling properties. In addition to these results, we also succeed in developing new synthesis method of aluminosilicate )zeolite which would be useful as host for molecular catalyst. We found that a molecular cluster with six Si and a Al atom afforded zeolite L and W at around 160 degreeC under hydrothermal condition. It is noteworthy that this processes do not need any pretreatment of precursors which is needed in the conventional methods.

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  • Fablication of chemical energy carrier system by fusion of non-precious metals

    Grant number:16H04123  2016.4 - 2019.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)  Chuo University

    Chang Ho-Chol

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    Grant amount: \17160000 ( Direct Cost: \13200000 、 Indirect Cost: \3960000 )

    (1) We demonstrated that the photochemical hydrogen evolution reaction of our system can be driven by purely ligand-based processes that have been proved by the isolation of intermediates with ligand-based proton-coupled mixed valent ligands. We also experimentally proved that our system can be modulated by changing metal ions (such as from Fe(II) with d6 electrons to Mn(II) with d5 electrons, substituents (such as t-butyl and Cl groups) on the ligands. (2) To develop photodehydrogenation catalyst, we demonstrated the effects of metal ions (such as Mg(II), Mn(II), Co(II), Zn(II)), substituents (such as t-butyl and Cl groups), and spin states of metal center. As results, the catalytic activity has significantly increased by these chemical factors.

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  • Catalytic reduction of CO2 in polarized reaction field made by non-innocent-type non-precious metal complexes

    Grant number:16K13967  2016.4 - 2018.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Challenging Exploratory Research  Chuo University

    CHANG HO-CHOL

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    Grant amount: \3640000 ( Direct Cost: \2800000 、 Indirect Cost: \840000 )

    In this project, we found that (a) the direct photochemical carboxylation of C-H bonds in aromatic diamines with CO2 by o-phenylenediamine Fe(II) complex in the absence of electron donor and base, (b) the promotion effect of the Fe(II) ion in photochemical carboxylation,
    (c) and the mechanistic studies on photochemical hydrogen generation by using 2-methylpropane-2-thiol as a radical trapping reagent. Although the carboxylation reaction presented in this work is a stoichiometric reaction, it is nevertheless the first example of atom- and step-economic direct carboxylation of the C-H bonds in benzene rings and that does not require potentially reactive electron donors or strong bases.

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  • 非平衡反応場における金属錯体の自励双安定化

    2012.4 - 2014.3

    文部科学省  科学研究費補助金(日本学術振興会・文部科学省)-挑戦的萌芽研究 

    張 浩徹

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    Authorship:Principal investigator  Grant type:Competitive

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  • Construction of Luminescent Chromic Metal Complexes with Dynamic Ordering

    Grant number:23350025  2011.4 - 2014.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)  Hokkaido University

    KATO Masako, KOBAYASHI Atsushi, CHANG Ho-chol

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    Grant amount: \20410000 ( Direct Cost: \15700000 、 Indirect Cost: \4710000 )

    The purpose of this project is to construct novel assembled metal complex systems with dynamical ordering by using various intermolecular interactions such as metal-metal, pai-pai, hydrophobic, and hydrogen bonding interactions. In this concept, we have developed luminescent metal complexes which exhibit unique chromic behaviors in response to the various environmental stimuli such as vapor, light, and heat: 1) Vapochromic coordination polymers and suplamolecular restorable systems based on luminescent platinum(II) or ruthenium(II) complexes; 2) Luminescent dinuclear copper(I) complexes which exhibit luminescence changes induced by light and vapor; 3) Vapor and mechanically induced chromic behavior of platinum(II) complexes with a dimer-of-dimer motif and the effect of hetero metal ions.

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  • レドックス活性配位子の導入による非貴金属型水分解触媒の創成

    2012.4 - 2013.10

    日揮財団  奨学寄付金 

    張 浩徹

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    Authorship:Principal investigator  Grant type:Competitive

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  • レドックス活性配位子を導入した3d金属水分解触媒の創成

    2012.4 - 2013.3

    松籟科学技術振興財団  奨学寄付金 

    張 浩徹

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    Authorship:Principal investigator  Grant type:Competitive

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  • 光分子集積を指向した金属錯体の光融解と光結晶化

    2010.4 - 2011.10

    文部科学省  科学研究費補助金(日本学術振興会・文部科学省)-基盤研究(C) 

    張 浩徹

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  • An innovative platform for non-thermal, synchronic control of macroscopic phase and molecular properties in micro scale.

    Grant number:18685006  2006 - 2008

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Young Scientists (A)  Kyoto University

    CHANG Ho-chol

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    Grant amount: \30290000 ( Direct Cost: \23300000 、 Indirect Cost: \6990000 )

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  • 結晶融解法を用いたレドックス活性金属錯体の配向及び電界効果トランジスタ能制御

    Grant number:18655056  2006 - 2007

    日本学術振興会  科学研究費助成事業  萌芽研究  京都大学

    張 浩徹

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    Grant amount: \3600000 ( Direct Cost: \3600000 )

    本研究は、課題(A)「モジュール化学の展開とバルク物性制御」(平成18年度)、課題(B)「基盤環境と結晶化プロセスによる薄膜結晶相制御」(平成18-19年度)、課題(C)「アンバイポーラFET能の最適化条件の探索」(平成19年度)から構成される。初年度における1)[M(Cat)(Cnbpy)](M=Pt,Pd);Cat=catecholate,n=9-17)群や[M(Bdt)(Cnbpy)](M=Pt,Pd);Bdt=benezenedithiolato,n=9-17]群が等方性液体から結晶化する際にシリコン基盤上にて一軸配向すること、2)[Pt(Bdt)(Mebpy)]が新規p型FET活性物質である、最後に3)これらの分子が示す一軸配向性に長鎖に含まれる炭素数依存性があることを基にH19年度の研究を進めた。その結果、1)PMMA処理を施したシリコン基板上にて真空蒸着法で作成した薄膜Ni錯体がCa電極を用いることで4.3*10_3及び1.6*10_2 cm2/Vsのホール及び電子移動度を示すことを明らかにした。このようにp,n型バランスのとれた高い移動度を示す物質は非常に限られている。またこの錯体の類似骨格に長鎖を付与することで融解法により同様の性質が得られることを強く示す結果である。2)また我々は結晶及び液晶を示す錯体を用いて融解法によりITO|[Pt(R-Cat)(C8,10bpy)]|ITO型デバイスを作成し、I-V特性を測定したとこ特にポリイミド処理を施したITO基盤上で良好な照射光強度とI値の相関を見いだした。またITO|錯体|AIのデバイスにおいて僅かであるが光電変換特性を見いだした。以上の結果により融解法がFETデバイスのみならず太陽電池などの光電変換デバイスへの応用が過当となることを示す結果を得た。

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  • Syntheses of Innovative Porous Metal Complexes and Their Functional Chemistry

    Grant number:16074209  2004 - 2007

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research on Priority Areas  Kyoto University

    KITAGAWA Susumu, OHBA Masaaki, CHANG Ho-Chol, UEMURA Takashi, INAGAKI Shinji

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    Grant amount: \127000000 ( Direct Cost: \127000000 )

    In this project, we aim to develop functions with the characteristics of porous coordination polymers (PCPs)such as designable surface functionality, high regularity, and framework flexibility Highly controlled acetylene accommodation in a microporous coordination polymer has been accomplished by preparing a pore surface specific for acetylenic hydrogen atoms. The acetylene can be packed 200 times as densely as the limitation value without explosion. The adsorbed acetylene molecules are highly stabilized by the double hydrogen bonded supports in nanosized pores, which mere revealed by direct observation of the adsorbed molecules using the results of in-situ synchrotron XRD measurements and by first principles calculations.
    We have designed and synthesized a bimodal microporous twofold interpenetrating PCP with two types of channel for anionic N(CN)2- and neutral water molecules, respectively. The dehydrated framework provides a dual function of specific anion exchange of free N(CN)2- for the smaller N3- anions and selective gas sorption. The N3--exchanged framework leads to a dislocation of the mutual positions of the two interpenetrating frameworks, resulting in an increase in the effective pore size in one of the counterparts of the channels and a higher accommodation of adsorbate than in the as-synthesized framework.
    A few substituted acetylenes spontaneously polymerized in one-dimensional nanochannels of PCPs with pillared layer structure. In this polymerization system, only mono-substituted acetylenes with electron-withdrawing group could be polymerized in the channels. suggesting that strong hydrogen bonding interaction between the monomers and surface carboxylate moiety in the frameworks is a key factor to initiate the polymerization.

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  • 酸化還元活性金属錯体の薄膜構造精密制御とバイポーラトランジスタへの応用

    Grant number:16750118  2005    

    日本学術振興会  科学研究費助成事業  若手研究(B)  京都大学

    張 浩徹

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    Grant amount: \3300000 ( Direct Cost: \3300000 )

    本研究では、(1)酸化及び還元に対し活性な分子性金属錯体の薄膜相における精密構造解析を行い、薄膜相における高均一性分子配列制御及びバルク結晶相とは異なる"薄膜結晶相"の探索を第一目的とした。また本研究では、(2)酸化還元活性オルトキノン金属錯体を用いて、配位子上で混合原子価状態をつくりだし、ドナー性配位子部位とアクセプター性配位子部位の直接的な分子間相互作用により、有効な重なり積分とバンドの広がりを促し、バンド伝導に基づいた高速の移動度を達成することを目的とした。最後に(3)バイポーラTFT活性能を評価することで作成した薄層相の構造均一性を評価し、「薄膜相構造-電子物性相関」を総合的に明らかにする。具体的課題としては、より均一性の高い(単結晶性の高い)薄膜相を得るために、薄膜成長条件(錯体分子構造、蒸着速度、基盤温度、蒸着速度、キャリアガス種、基盤種等)の最適化を行う。またより高い移動度を達成することを目的に、薄膜の単結晶性の向上や酸化還元電位(HOMO-LUMO準位、ギャップ)の最適化を遂行すると共に、バンド伝導に必要な錯体分子間相互作用の増強に基づくデバイス能の向上を試み、世界に先駆的に錯体分子バイポーラTFTを開発することを目的とする。昨年度は酸化及び還元活性なビスジイミノセミキノネート錯体を用いて電界効果トランジスタ能の発現に初めて成功した。分子性金属錯体のFET活性能に関する報告例は皆無に近い。得られた薄膜性錯体は理想的に駆動するp型デバイスであり、移動度は0.0138cm2/Vs(飽和領域)である。また、デバイス特性は真空中及び大気中でも変化なく、薄膜の安定性も示された。以上の知見をもとに、同様の錯体である[Pt(diiminosemiquinonate)2],[Pd(diiminosemiquinonate)2]を用いたFETを開発し、金属種依存性を明らかにした。Ni,Pt,Pdのうち、Ni錯体が最も高い移動度を示した。本年度は更に、目的であるアンバイポーラ能を発現することを目的に、Ni錯体を用い、基盤にPMMAを処理し、電極にはCaを用いることでn型FET能の発現に成功した。またアニーリングにより、n型特性が発現することも成功した。これは加熱処理による電子トラップサイトの減少が原因と考えられる。以上得られた成果により世界にさきがけて金属錯体を用いたアンバイポーラ型FETの創成に成功したと言える。

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  • 混合原子価金属錯体を用いた単一分子素子とそのナノ集合体の機能創製

    Grant number:14740362  2002 - 2003

    日本学術振興会  科学研究費助成事業  若手研究(B)  京都大学

    張 浩徹

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    Grant amount: \3800000 ( Direct Cost: \3800000 )

    近年、化学的及び物理的手法を駆使した単分子レベルにおける状態変換や、ナノスケール特有の量子効果に基づいた単分子電子素子の開発が注目を集めている。本研究ではそのための最重要課題として、(1)物理的及び化学的摂動に対し応答し、分子内電子状態を変換しうる双安定性分子の構築と(2)引き起こされる分子内状態変換を隣接分子へ伝達しうる超分子システムを合理的に構築することに注目し研究を遂行している。特に、「混合原子価状態」という非対称的な電子構造を「分子が持つ情報」として活用する事で、金属錯体ならではの性質を示す電子素子を開発することを目的としている。
    本研究では、2年間の研究過程に、長鎖アルキル基を有する新規平面性Pd,Pt錯体の合成に成功し、その結晶構造解析により構造を明らかにすると同時に、ナノサイズの混合原子価金属錯体を合成することを目的に、原子価互変異性に基づく双安定性を示すCoキノン錯体をモジュールとした新規クラスターの合成方法を見出した。得られた新規5,6,10核クラスター錯体は、金属及び配位子ともに電子スピンを有し、かつ配位子が混合原子価状態である、これまでにない類を見ないナノサイズクラスターである。本研究ではこれらの分子構造を明らかにすると共に、その生成機構並びに磁性について検討を行い、錯体が外場により、金属-配位子間又は配位子間の電荷および電子移動が誘起される可能性を確認した。また本クラスター錯体は、反応活性なセミキノネートとフェニレンジアミン間の脱水縮合反応がその形成の引き金となり生成することを明らかとし、他種金属イオンにも応用可能であり、且つ多様なナノサイズ金属錯体クラスターの創成に有用な反応であることを示した。

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  • 水溶性レセプターの合理的合成法の開発

    Grant number:14044045  2002 - 2003

    日本学術振興会  科学研究費助成事業  特定領域研究 

    水谷 義, 張 浩徹

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    Grant amount: \4100000 ( Direct Cost: \4100000 )

    水溶性レセプターの合成は、タンパク質やDNAなどの生体高分子の分子認識機構の解明や生理活性分子の分離・検出などを行うための基本となるものであるが、これまでに、合成方法の立場から詳細な検討は行われてきていない。特に、疎水性と親水性の二面性をもつ分子を合成する必要があり、親水基の導入のタイミングなどが、合成の成否を分けるものと考えられる。われわれは、これまでの研究で、疎水性のポルフィリンを骨格に用いて分子認識サイトを構築し、これに親水性部位を導入する方法についていろいろと検討してきた。
    水溶性を付与するための官能基としてアニオン性のカルボキシレートを多数導入したポルフィリンについては、以前に報告したが、この分子は、不十分な疎水空間を有することが分かった。そこで、中性の親水性官能基としてポリエチレンオキシドを導入したポルフィリンの合成方法を検討した。
    合成方法としては、末端にカルボン酸基をもつポルフィリンをまず、合成し、これを、末端がアミノ基のポリエチレンオキシドと縮合剤でカップリングさせた。このようにして合成した水溶性ポルフィリンレセプターは、いろいろなアミンを水中で取り込み、特に効果的に疎水相互作用が働くことが分かった。特に、いろいろなアルキル鎖の長さをもつ4-アルキルピリジンとの結合定数を吸収スペクトルで測定すると、アルキル基の炭素が1つ増えるごとに3.5kJ/mol分の結合自由エネルギーの増加が見られた。これは、水とオクタノールなどの分配係数から見積もったメチレン基1つあたりの自由エネルギーとほぼ同じであり、水中に理想的な疎水空間が構築されていることが分かった。
    水溶性高分子と疎水性人工レセプターの組み合わせで、いろいろなレセプターの合成が可能であると期待でき、将来のいろいろな展望を示すことができた。

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  • Functional Chemistry of Guest-responsive Nano Space Created by Coordination Polymers

    Grant number:13440195  2001 - 2002

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)  KYOTO UNIVERSITY

    KITAGAWA Susumu, CHANG Ho-Chol

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    Grant amount: \12900000 ( Direct Cost: \12900000 )

    The advent of robust coordination polymer frameworks demonstrated that solid coordination compounds were acquiring an important position in porous materials and expanding materials-directed coordination chemistry.
    However, this sort of compounds are considered to be static materials.
    If we take advantages of coordination polymers, we could provide dynamic materials with flexible frameworks, which are so-called 3rd generation compound. In this manuscript we focus on a pillared-layer motif relevant for this sort of frameworks, which create not only a channel size and shape but also a chemical functionality simply by modifying the pillar module.
    In this manuscript, we succeeded in designing and realizing a new pillared-layer type coordination polymer.
    1) The obtained compound is rationally synthesized by using a pillared layer framework. By taking advantages of the framework, we succeeded in creating a hydrogen bonding channel with 1,2-dipyridylglycoI (dpyg), whose interaction is used only for guests having hydrogen bonding capability.
    This type of framework is very few
    Coordination polymers with two-dimensional frameworks with a double-edged axe-shaped motif have also been synthesized from reactions of cobalt(II) thiocyanate with N-(3-pyridy) isonicotinamide (3-pia) or N-(3-pyridyl)nicotinamide (3-pna). Crystal-to-crystal transformation accompanying inclusion of guest molecules by dynamically switching amide groups in the structure has been found.
    2) This novel network exhibits a crystal to crystal transformation under guest vapor/reduced atmosphere.
    3) What is most interesting is "finding of hysteretic sorption properties" for water or methanol vapor. The framework conversion from the apohost to adsorbed one is driven by hydrogen bonding interaction with the guests, indicating that the framework responds to a specific guest molecule and changes its microcavities into those well-suited for the shape and/or affinity of the guest molecule. This unique properties opened up a new dimension to materials-directed coordination chemistry.

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  • 多元素環状化合物を用いた分子認識素子の開発

    Grant number:13029054  2001    

    日本学術振興会  科学研究費助成事業  特定領域研究(A)  京都大学

    水谷 義, 張 浩徹

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    Grant amount: \2200000 ( Direct Cost: \2200000 )

    タンパク質ではない人工分子で生理活性物質を特異的に認識し捕捉するような人工レセプターの研究は、環境問題、エネルギー問題などとの関係から興味深く、また、遺伝子情報からの新しい創薬の可能性とも関連して重要な研究テーマである。
    われわれは、水酸基をもつ多くの生理活性物質が知られているにもかかわらず、そのようなアルコール・フェノールに対して特異的に結合するような人工レセプター、あるいは、認識モチーフがほとんど知られていないことに着目し、アルコール・フェノールを水中で捕捉する人工レセプターの設計と合成について検討している。
    ポルフィリンの剛直な骨格と、疎水的な相互作用面、ポルフィリンの中心金属による酸素原子に対する親和性を協同的に利用することで、アルコール・フェノールを認識するモチーフとなるのではないかと考え、種々のポルフィリン誘導体の金属錯体を合成した。ポルフィリンの骨格としては、金属のルイス酸点の近傍に基、水酸基の認識において協同的に働くと期待できるルイス塩基点を導入するために、meso-位にキノリル基、o-エステル置換フェニル基をもつポルフィリン誘導体を新しく合成した。また、中心の金属としては、アルミニウム、マグネシウム、亜鉛などをポルフィリンに挿入し、金属イオンの違いによる酸素親和性の相違を検討した。
    その結果、アルミニウムポルフィリンを用いて、有機溶媒中でフェノールの結合定数を評価すると、亜鉛、マグネシウムポルフィリンよりも大きな結合定数が得られ、酸素原子をもつゲストに対する親和性が大きな分子を合成することが可能であった。しかし、同様の実験を水中で行うと、アルミニウムポルフィリンよりも、むしろ、亜鉛ポルフィリンの方が大きな親和性が見られ、アルミニウムポルフィリンは溶媒効果をより強く受けることが明らかとなった。

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  • Preparation of Electric Field-Applicable Solid State NMR Probe

    Grant number:12554031  2000 - 2001

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)  KYOTO UNIVERSITY

    KITAGAWA Susumu, MIZUTANI Tadashi, ENDO Kazuo, FUJITO Teruaki, CHANG Ho-chol

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    Grant amount: \10300000 ( Direct Cost: \10300000 )

    We have constructed a new NMR probe for the measurement of solid state NMR spectra under the electric field. The high-power amplifier was used for the observation of the spectra. The sample in the dyfron plate vessel. The sample stage was mounted in the goniohead so that the stage can be rotated. Consequently, the electric field can be applied to the sample in the region of -90 - +90°against the magnetic field. To avoid an evolution of heat, cooled air was supplied to the stage by the tube. High-voltage rapid electric amplifier was installed, which can apply direct voltage of 0-500 V to the sample. Using the probe, we have measured ^<13>C NMR spectra of 4-cyano-4'-n-pentylbiphenyl (5CB), which shows a nematic liquid crystal phase at room temperature, by stepwise increase of a electric field. The obtained spectra are found to be in good agreement with previous reports on a local motion and an electronic structures of 5CB. In addition we have used the probe to characterize microporous coordination polymers with guest inclusion ability.

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  • 酸化還元活性金属錯体液晶における動的構造と物性制御

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    Grant type:Competitive

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