2006 Fiscal Year Final Research Report Summary
Preparation and Properties of Network Complexes with Meta-Metal Bond Redox Sites in Mixed Oxidation State
| Project/Area Number |
17550057
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Inorganic chemistry
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| Research Institution | Kyoto University |
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Principal Investigator |
KAWAMURA Takashi Kyoto University, Graduate School of Engineering, Parttime Researcher, 工学研究科, 非常勤研究員 (40026125)
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| Project Period (FY) |
2005 – 2006
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| Keywords | Supramolecular Chemistry / Mixed valent complex / Porous coordination polymer / Conducting complex / Adsorption / Rhodium / Ruthenium / Metal-metal bond |
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| Research Abstract |
Conductive porous coordination polymer is an interesting material because its conductivity may shift depending on adsorbate molecules. This is an electrical transformation of molecular recognition. An important key for conductive material is presence of redox sites in mixed oxidation state. We adopted a paddlewheel type dirhodium complex as the redox active site. Its neutral and monocationic complexes are reacted with sodium iodide to give a diamondoid network material in a mixed oxidation state and it was a semiconductor with σ = 3.8 x 10^<-4> S cm^<-1> and Arrhenius activation energy of 160 meV. Electronic spectra of this and related complexes suggested that the conductance is well modeled by a small polaron mechanism with a quite small transfer interaction (β = 33 meV). When pressure increases to 2 GPa, the conductivity increased monotonically to a three times larger value than observed at the atmospheric pressure without any indication of phase-transition. Upon dehydration of the current semiconductor, the conductivity decreased orders of magnitudes. The dehydrated semiconductor adsorbs some small molecules such as CO_2, C_2H_2, CH_3OH, and CH_3CN. When the dehydrated semiconductor adsorbed CH_3OH or CH_3CN, its conductivity increased. The geometrical structure of the current complex is not very strong to execute detailed study on the adsorbate dependence of its conductivity. We also synthesized a series halide-bridged terakis(acetamidato)diruthenium chain complexes. Characteristics of these complexes are large zero-field splitting constant and small exchange interactions between neighboring diruthenium sites
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