| Project/Area Number |
08404045
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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 |
Inorganic chemistry
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
MATSUDA Yoshihisa Kyushu univ., Graduate School of Science, Prof., 大学院・理学研究科, 教授 (10037757)
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| Co-Investigator(Kenkyū-buntansha) |
OKAUE Yoshihiro Kyushu univ., Graduate School of Science, Research Asoociate, 大学院・理学研究科, 助手 (10194333)
ISOBE Toshiyuki Kyushu univ., Graduate School of Social and Cultural Studies, Prof., 大学院・比較社会文化研究科, 教授 (90037242)
YOKOYAMA Takushi Kyushu univ., Graduate School of Science, As. Prof., 大学院・理学研究科, 助教授 (20136419)
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| Project Period (FY) |
1996 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥36,400,000 (Direct Cost: ¥36,400,000)
Fiscal Year 1999: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1998: ¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 1997: ¥11,800,000 (Direct Cost: ¥11,800,000)
Fiscal Year 1996: ¥19,200,000 (Direct Cost: ¥19,200,000)
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| Keywords | Atomic hydrogen / Encapsulation / Silsesquioxane / ESR / Relaxation time / Electron spin echo / シロキサン |
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| Research Abstract |
1. A mixture of silsesquioxanes, HィイD2nィエD2(SioィイD21.5ィエD2)ィイD2nィエD2 was synthesized by controlled hydrolysis of trichlorosilane. Separation and purification of sphero-octamer, -decamer, and -dodecamer which have cage structure were achieved by using HPLC. Lipophilic or hydrophilic substituent groups of several sizes were introduced to afford cage silsesquioxanes of different structure and physicochemical properties.
2. Cage molecules in solid, solution in organic solvent, or adsorbed phase were irradiated with γ-ray to encapsulate the hydrogen atom. It is essential for the efficient encapsulation of hydrogen that the encapsulating cage has bulky terminal substituent groups and that the cage has open space around them in the solid state. An alternative way to encapsulate hydrogen efficiently is to disperse the cages on an adsorbing medium.
3. The larger cages than octamer do not encapsulate hydrogen at room temperature. The hydrogen encapsulated in the expanded cages at liquid nitrogen temperature eliminates at low temperature through pentameric ring.
4. The lipophilic octameric cage eliminates the encapsulated hydrogen hardly in organic solvents compared to solid state.
5. Spin Hamiltonian parameters of hydrogen atoms in several cages indicate that the extent of the 1s orbital varied by the size of the cage and that mixing of 2p electron into the 1s is little affected by the size of the cage.
6. Molecular oxygen outside of the cage reduces the relaxation time of the spin of the encapsulated hydrogen. TィイD21ィエD2 is affected more efficiently than TィイD22ィエD2 indicating that rapid molecular motion of triplet oxygen is responsible for the reduction of the relaxation times.
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