2000 Fiscal Year Final Research Report Summary
Partially Oxidized Transition-Metal Clusters with High Electrical Conductance
| Project/Area Number |
10554038
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Inorganic chemistry
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| Research Institution | Gifu University |
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Principal Investigator |
KAWAMURA Takashi Gifu University, Faculty of Engineering, Professor, 工学部, 教授 (40026125)
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| Co-Investigator(Kenkyū-buntansha) |
EBIHARA Masahiro Gifu University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (80201961)
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| Project Period (FY) |
1998 – 2000
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| Keywords | cluster complex / ionic radical salt / magnetism / crystal structure / π-stack / electrical conductance / doping / δ-π interaction |
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| Research Abstract |
This project aims to develop partially oxidized material by utilizing easily polarizable and delocalizable electronic characteristics of MM bonds in transition-metal cluster complexes. The shifts of the geometries induced by one-electron oxidation of dirhodium complexes were examined experimentally and theoretically to show that the shifts can be utilized to assign the molecular orbital involved in the ionization. The intramolecular δ-π electronic interaction between MM bond and bridging aromatic ligands in paddlewheel-type dirhodium cationic radical salts has been estimated to induce around 10% of the odd-electron density on the MM bond is delocalized onto the π system of each of the bridging ligands based on the ^1H NMR paramagnetic shifts. Intermolecular electronic interaction in π stack arrangement of such type of cationic radical molecules in crystals of their salts was evaluated based on their magnetism. Only short intermolecular contacts between high-spin-density carbon atoms induce detectable magnetic interaction. Mechanic mixture of such radical salts with the corresponding neutral complexes induced 10^4 increase of their electrical conductance. The mixing was shown to induce doping of electron from the neutral complex to the cationic radical salt, and all the odd-electrons in the mixture hop not only over each of molecules in a crystalline particle but also over particles in the mixture as shown by ESR.X-ray powder diffraction data showed that no new phase was developed by the mixing. Tetrarhodium complexes with new cage-type core structure have been synthesized and their reactivity has been examined to develop a new synthetic method for mixed-ligand dirhodium complexes. Some catalytic cyanation reactions of olefinic compounds have been also developed.
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