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Molecular Design of Asymmetric Metal Dinuclear Complexes towards Molecular Switching of Intramolecular Electron Transfer

Research Project

Project/Area Number 02640474
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field 無機・錯塩・放射化学
Research InstitutionMie University

Principal Investigator

HAGA Masa-aki  Mie University, Faculty of Education, Professor, 教育学部, 教授 (70115723)

Project Period (FY) 1990 – 1991
Project Status Completed (Fiscal Year 1991)
Budget Amount *help
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1991: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1990: ¥1,700,000 (Direct Cost: ¥1,700,000)
KeywordsDinuclear Complexes. / Molecular Switching / Ruthenium / Mixed-Valence Complexes / Proton Transfer / Redox Reaction / ルテニウム錯体 / 金属二核錯体 / 分子内電子移動 / スイッチング素子 / 分子素子
Research Abstract

Supramolecular assemblies composing of oligonuclear metal complexes with bridging ligands can be considered to have a potential as a building block for synthesizing a molecular level chip such as molecular size "wires, " and "rectifiers". We focus our attention on the "molecular switching" by proton transfer in metal complexes, since the proton transfer can be regarded as a trigger signal to change the metal-metal interaction or the structure of the complex. In order to get the basic information for the design of molecular-level devices such as a molecular switch, new mononuclear and hetero-dinuclear complexes, [M(L)_2(bpbimH_2)]^<2+> and [M(L^1)_2(bpbimH_2)M'(L^2)_2]^<4+> (M and M' = Ru, Rh, and/or Os ; L^1 or L^2 = 2, 2'-bipyridine (bpy), 1, 10-phenanthroline (phen), or 4.4'-dimethylbipyridine (dmbpy)), containing dinucleating ligand 2, 2'-bis- (2-pyridyl)-bibenzimidazole (bpbimH_2) have been prepared. Both absorption spectra and oxidation potential are strongly dependent on the solu … More tion pH, which is responsible for the N-H deprotonation on the coordinated bpbimH_2 ligand. The mononuclear Ru and Os complexes act not only as a basic acid but also as a diacidic base, while hetero-dinuclear complexes essentially act as a dibasic acid. The proton-tcoupled electron transfer reaction is proved by E_<1/2> - pH plot (Pourbaix diagram). The number of electron participated in the proton- coupled electron transfer reaction essentially depends on the redox activity on the second metal site. The pK_a values of the complexes reflect on both metal and its oxidation states, M (II) and M (III). The pK_a values of the mixed-valence dinuclear complexes are quite close to those of each M (II) and M (III) component, which suggests that the mixed-valence complexes have a localized valence structure. The mixed-valence complexes bridged by the protonated ligand bpbimH_2 exhibit the intervalence (IT) band at 7300 cm^<-1> for M = Ru, and at 9100 cm^<-1> for M = Os, respectively. When the bridging ligand is deprotonated, this IT band is shifted to the lower energy at 5880 cm^<-1> for M = Ru, and 7700 cm^<-1> for M = Os, and intensified. The degree of metal-metal interaction of the deprotonated dinuclear complexes becomes 4-6 times larger than that of the protonated complexes. This proton-induced change of metal-metal interaction can be rationalized by change of HOMO energy levels on deprotonation or protonation in the bridging ligands. Thus, the proton transfer in the bpbimH_2 bridging dinuclear complexes can be elucidated to serve as a trigger signal for switching the metal-metal minteraction. Less

Report

(3 results)
  • 1991 Annual Research Report   Final Research Report Summary
  • 1990 Annual Research Report
  • Research Products

    (22 results)

All Other

All Publications (22 results)

  • [Publications] Masa-aki Haga,A.M.Bond: "Electrce chemistry of Symmetrical and Asymmetrical Dinuclear Ruthenium,and Mixed-Metal 2,2'-Bipyridine Complexes Bridged by 2,2'-Bibenzimidazolae" Inorg Chem. 30. 475-480 (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Takeshi Ohno,Kouichi Nozaki,Masa-aki Haga: "Electron Transfer,Energy Transfer,and Excited-state Annihilation in Binuclear Compounds of Ruthenium (II)" Advances in Chemistry,"Electron Transfer in Inorganic,Organic, and Biological Systems. 228. 215-228 (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Masa-aki Haga,Tomo-aki Ano,Kenji Kano,Shinichi Yamabe: "Proton-Induced Switching of Metal-Metal Interactions in Dinuclear Ruthemium and Osmium Complexes Bridged by 2,2'-Bis(2-pyridyl)bibenz-imidazole" Inorg Chem. 30. 3843-3849 (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Takeshi Ohno,Kouchi Nozaki,Masa-aki Haga: "Photoexcited States of Bi-Ruthenium(II)Compounds Bridged by Bis-2,2'-(2-Pyridyl)-Bibenzimidazole or Bi-(2-Pyridyl-2'-Benzimidazolyl)ethane" Inorg Clem. 31. 548-555 (1992)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] 芳賀 正明: "機能性を目指したルテニウム二核錯体" 化学と工業. 43. 1288-1289 (1990)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Takeshi Ohno,Kouichi Nozaki,Masaーaki Haga(分担): "“Photochemical Processes in Organized Molecular Systems"Edited by K.Honda" NorthーHolland, 538 (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] M. Haga and A. M. Bond: ""Electrochemistry of Symmetrical and Asymmetrical Dinuclear Ruthenium, Osmium, and Mixed-Metal 2, 2'-Bipyridine Complexes Bridged by 2, 2'-Bibenzimidazolate"" Inorg. Chem.30. 475-480 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] T. Ohno, K. Nozaki, N. Ikeda, and M. Haga: ""Electron Transfer, Energy Transfer, and Excited-State Annihilation in Binuclear Compounds of Ruthenium (II)"" Advances in Chemistry. No. 228, "Electron Transfer in Inorganic, Organic. and Biological Systems". 215-228 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] M. Haga, T. Ano, K. Kano, and S. Yamabe: ""Proton-Induced Switching of Metal-Metal Interactions in Dinuclear Ruthenium and Osmium Complexes Bridged by 2, 2'-Bis 2-pyridyl) bibenzimidazole"" Inorg. Chem.30. 3843-3849 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] T. Ohno, K. Nozaki, and M. Haga: ""Photoexcited States of Bi-Ruthenium (II) Compounds Bridged by Bis-2, 2'- (2-Pyridyl) -Bibenzimidazole or Bi- (2-Pyridyl-2'- Benzimidazole) ethane"" Inorg. Chem.31. 548-555 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] M. Haga: ""Ruthenium Dinuclear Complexes Towards Molecular Functionality"" Kagaku To Kogyou. 43. 1288-1289 (1990)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] T. Ohno, K. Nozaki, and M. Haga: ""Intramolecular Electron Transfer and Energy Transfer in Bimetalated Compounds"" Photochemical Processes in Organized Molecular Systems. Edited by Prof. K. Honda, North-Holland. 151-161 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Masaーaki Haga & A.M.Bond: "Electrochemistry of Symmetrical and Asymmetrical Dinuclear Ruthenium,Osmium,and MixedーMetal 2,2'ーBipyridine Complexes Bridged by 2,2'ーBibenzimidazole" Inorg.Chem. 30. 475-480 (1991)

    • Related Report
      1991 Annual Research Report
  • [Publications] Takeshi Ohno,Kouichi Nozaki,Masaーaki Haga: "Electron Transfer,Energy Transfer,and ExcitedーState Annihilation in Binuclear Compounds of Ruthenium(II)" Advances in Chemistry “Electron Transfer in Inorganic,Organic and Biological Systems. 228. 215-228 (1991)

    • Related Report
      1991 Annual Research Report
  • [Publications] Masaーaki Haga,Tomoーaki Ano,Kenji Kano: "ProtonーInduced Switching of MetalーMetal Interactions in Dinuclear Ruthenium and Osmium Complexes Bridged by 2,2'ーBis(2ーpyridyl)bibenzimidazole" Inorg.Chem.30. 3843-3849 (1991)

    • Related Report
      1991 Annual Research Report
  • [Publications] Takeshi Ohno,Kouichi Nozaki,Masaーaki Haga: "Photo excited States of BiーRuthenium(II) Compounds Bridged by Bisー2,2'ー(2ーPyridyl)ーBibenzimidazole or Bi(2ーPyridylー2'ーBenzimidazole) ethane" Inorg.Chem. 31. 548-555 (1992)

    • Related Report
      1991 Annual Research Report
  • [Publications] K.Honda (Ed.),Takeshi Ohno,Kouichi Nozaki,Masaーaki Haga (分担): "“Photochemical Processes in Organized Molecular Systems"" Elsevier, 538 (1991)

    • Related Report
      1991 Annual Research Report
  • [Publications] 芳賀 正明: "機能性を目指したルテニウム二核錯体" 化学と工業. 43. 1288-1289 (1990)

    • Related Report
      1990 Annual Research Report
  • [Publications] Masaーaki Haga: "Electrochemistry of Symmetrical and Asymmetrical Binuclear Ruthenium,Osmium and Mixed Metal Bipyridine Complexes Bridged by 2,2'ーBibenzimidazolate" Inorg.Chem. 30. 475-480 (1991)

    • Related Report
      1990 Annual Research Report
  • [Publications] Takeshi Ohno: "Intramolecular Electron Transfer and Energy Transfer in Bimetalated Compounds" Photochemical Processes in Organized Molecular Systems. (1991)

    • Related Report
      1990 Annual Research Report
  • [Publications] Masaーaki Haga: "Comparative Studies on Charge Distribution for Ruthenium and Osmium Quinone Complexes" Inorg.Chem. 29. 3795-3799 (1990)

    • Related Report
      1990 Annual Research Report
  • [Publications] Masaーaki Haga: "ProtonーInduced Switching of Metalーmetal Interaction in Dinuclear Ruthenium and Osmium Complexes Bridged By Bis(2ーPyridyl)Bibenzimidazole" Inorg.Chem.

    • Related Report
      1990 Annual Research Report

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Published: 1990-04-01   Modified: 2016-04-21  

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