2005 Fiscal Year Final Research Report Summary
In situ observation of unstable intermediates by X-ray crystallography
| Project/Area Number |
16550050
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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 | The University of Tokyo |
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Principal Investigator |
KAWANO Masaki The University of Tokyo, Graduate School of Engineering, Associate Professor, 大学院・工学系研究科, 助教授 (30247217)
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| Co-Investigator(Kenkyū-buntansha) |
FUJITA Makoto The University of Tokyo, Graduate School of Engineering, Professor, 大学院・工学系研究科, 教授 (90209065)
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| Project Period (FY) |
2004 – 2005
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| Keywords | self-assembly / in situ observation / crystallography / crystalline state photoreaction / unsaturated complex / intermediate / host-guest / supramolecule |
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| Research Abstract |
In this project, we aim at investigation of novel properties of a nano-space of a self-assembled coordination cage, (1), via direct observation of photochemical reactions in the coordination space by X-ray crystallography. Reactive intermediates in organic reactions have been intensively studied with spectroscopic methods. However, crystallographic analysis has been hardly applied to direct observation of reactive intermediates. Our principal method is cryo-trapping techniques to freeze photo-induced short-lived intermediates at low temperatures. Here, we propose a supramolecular approach for crystallographic in situ observation to overcome pitfalls of conventional in situ techniques. The salient features of the supramolecular approach are that one can achieve high conversion rates without deterioration of single crystallinity and investigate to even non-crystalline molecules.
In situ crystallographic observation of an extremely labile coordinatively unsaturated transition-metal complex, Cp'Mn(CO)_2 (Cp' = methylcyclopentadienyl), was achieved by generating and trapping it within the confined cavity of a self-assembled cage in crystalline state at a low temperature. The labile target Cp'Mn(CO)_2 was formed by the photo-dissociation of CO ligand from stable Cp'Mn(CO)_3 which was accommodated within the cavity of the coordination cage. Being trapped in the cage at a low temperature, Cp'Mn(CO)_2 showed sufficient stability to be analyzed by X-ray crystallography. The diffraction study revealed that the 16-electron unsaturated Mn complex adopted a pyramidal geometry rather than a planar geometry.
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Research Products
(4 results)
