| Project/Area Number |
16205008
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Organic chemistry
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| Research Institution | University of Tsukuba |
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Principal Investigator |
SEKIGUCHI Akira University of Tsukuba, Graduate School of Pure and Applied Sciences, Professor, 大学院数理物質科学研究科, 教授 (90143164)
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| Co-Investigator(Kenkyū-buntansha) |
ICHINOHE Masaski University of Tsukuba, Graduate School of Pure and Applied Sciences, Associate Professor, 大学院数理物質科学研究科, 助教授 (90271858)
NAKAMOTO Masaski University of Tsukuba, Graduate School of Pure and Applied Sciences, Assistant Professor, 大学院数理物質科学研究科, 講師 (90334044)
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥50,960,000 (Direct Cost: ¥39,200,000、Indirect Cost: ¥11,760,000)
Fiscal Year 2006: ¥5,330,000 (Direct Cost: ¥4,100,000、Indirect Cost: ¥1,230,000)
Fiscal Year 2005: ¥5,200,000 (Direct Cost: ¥4,000,000、Indirect Cost: ¥1,200,000)
Fiscal Year 2004: ¥40,430,000 (Direct Cost: ¥31,100,000、Indirect Cost: ¥9,330,000)
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| Keywords | Element Chemistry / Heavier Group 14 Element / Main Group Element / Free Radical / Spin Chemistry / Cation / Anion / Oxidation and Reduction / 電子移動反応 / 電子状態 / 高周期元素 / ジシレン / ジシレンジアニオン / 金属置換シリルラジカル / シリレンアニオンラジカル / 高周期14族元素 / 高周期14族元素多重結合 / 高周期14族元素ラジカル種 / 高周期14族元素カチオン種 / 高周期14族元素アニオン種 |
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| Research Abstract |
The chemistry of the stable free radicals of heavier group 14 elements has been studied, including both neutral and charged radical species. The electronic and crystal structural features of these radicals, both in the solid state and in solution, are compared with each other. The most important parameters affecting the stability, geometry and electronic configuration of the radicals are investigated, based upon the experimental and computational data.
1. Upon one-electron reduction with ^tBuLi, tetrakis(di-tert-butylmethylsilyl)disilene produced a disilene anion radical, which was isolated in the form of its lithium salt. The molecular structure was established by X-ray crystallography, which showed a nearly orthogonal structure with the central Si-Si bond length of 2.341(5) Å. One of the central Si atoms has radical character, whereas the other Si atom has silyl anion character. The EPR study indicates that rapid spin exchange occurs between these central Si atoms on the EPR time scale.
2. The one-electron oxidation reaction of tris[di-tert-butyl(methyl)silyl]silyl and germyl anions with dichlorogermylene dioxane complex resulted in the formation of stable tris[di-tert-butyl(methyl)silyl]silyl and germyl radicals. The crystal structures of both silyl and germyl radicals showed a completely planar geometry around the radical centers. The EPR spectra indicate the p-character of both radicals, corresponding to a planar geometry and sp^2 hybridization of the radical centers.
3. The one-electron reduction of tris[di-tert-butyl(methyl)silyl]aluminum and-gallium with alkali metals (Li, Na, K) resulted in the formation of the corresponding radical anions [(tBu_2MeSi)_3Al]^-・and [(^tBu_2MeSi)_3Ga]・^-. Their molecular structures were established by X-ray crystallography, which showed a nearly planar geometry around the radical centers.
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