2002 Fiscal Year Final Research Report Summary
Chemical Functions of Transition Metal Assembled Complexes
| Project/Area Number |
10149102
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas (A)
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | Tohoku University |
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Principal Investigator |
ITO Tasuku Tohoku University, Graduate School of Science, Department of Chemistry, Professor, 大学院・理学研究科, 教授 (90007328)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIHARA Hiroshi The University of Tokyo, School of Science, Department of Chemistry, Profcssor, 大学院・理学系研究科, 教授 (70156090)
HAGA Masa-aki Chuo University, Department of Applied Chemistry, Professor, 理工学部, 教授 (70115723)
SASAKI Yoichi Hokkaido University, Graduate School of Science, Department of Chemistry, Professor, 大学院・理学研究科, 教授 (30004500)
FUJITA Makoto The University of Tokyo, Graduate School of Engineering, Department of Applied Chemistry, Professor, 大学院・工学系研究科, 教授 (90209065)
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| Project Period (FY) |
1998 – 2001
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| Keywords | redox behavior / mixed valence / multilayered complex / proton coupled electron transfer / multi-step electron transfer / transition metal assembled complexes / 可逆的結晶構造変化 |
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| Research Abstract |
Ito, using infrared spectral lineshape analysis in conjunction with infrared spectroelectrochemistry, determined the rates of intermolecular electron transfer between triruthenium cluster units in mixed valence complexes. The electron transfer rates along a "non symmetric potential energy surface" were elucidated and multiple electron transfer pathways and rates in a bridged cluster trimer were identified. As well as the electronic properties of cluster complexes, methods for assembling extended structures were examined. Using Pt complexes coordinated by high field ligands, strong unsupported Pt->M dative bonds were prepared, and when the Pt complexes were reacted with Ag ion or Rh dimers, linear and large multinuclear complexes were isolated.
Sasaki examined two areas: ligand-metal interactions and the synthesis of large complexes. In the first project, the stability of mixed valence states formed by ligand based redox processes were studied, and it was discovered that, when the metal
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centers and ligands mutually form mixed valence states, a "double mixed valence state" exists. In the second area hexanuclear rhenium complexes with new multidentate units were prepared and the structure of a rhenium hexamer having six large pyridylporphyrin ligands was determined.
Nishihara's research involved induced structural changes in transition metal complexes. Azo-conjugated transition metal complexes undergo a reversible trans-to-cis isomerization upon concomitant irradiation with a single UV light source and oxidation of the metal. Protonation of a ヲミ-conjugated ferrocene-anthraquinone system caused intermolecular electron transfer to occur. This leads to a novel structural change creating an ヲヌ^6-fulvene-cumulene Fe(II) complex. The structure of the proton attached complex and the properties of the unusually fluxional complex were elucidated.
Haga prepared multilayered metal complexes on a solid electrode through layer-by-layer growth. As well, a two-dimensional coordination system was developed at the air-water interface using Langmuir-Blodgett techniques.
Fujita furthered his research involving the construction of 2-D and 3-D complexes using 2,4,6-tris(4-pyridyl)triazine as a bridging ligand. An interesting 3-D network, which undergoes a reversible structural change in the solid state upon absorption/desorption of a guest molecule, was prepared. Less
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