| Project/Area Number |
14350449
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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 | 一般 |
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| Research Field |
工業物理化学
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| Research Institution | Tohoku University |
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Principal Investigator |
ITO Osamu Tohoku University, Institute of Multidisciplinary Research for Advanced Materials, Professor, 多元物質科学研究所, 教授 (30006332)
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| Co-Investigator(Kenkyū-buntansha) |
ARAKI Yasuyuki Tohoku University, Institute of Multidisciplinary Research for Advanced Materials, Research Associate, 多元物質科学研究所, 助手 (80361179)
藤塚 守 大阪大学, 産業科学研究所, 助教授 (40282040)
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| Project Period (FY) |
2002 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥14,600,000 (Direct Cost: ¥14,600,000)
Fiscal Year 2003: ¥4,700,000 (Direct Cost: ¥4,700,000)
Fiscal Year 2002: ¥9,900,000 (Direct Cost: ¥9,900,000)
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| Keywords | Fullerene / Porphyrin / Supramolecule / Charge Separation / Electron Transfer / Rotaxane / 光誘起電荷分離 / フェトム秒過渡吸収 / ナノ秒過渡吸収 / 時間分解蛍光スペクトル |
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| Research Abstract |
Self-Assembled electron donor-acceptor linked systems play a very important role in the artificial photosynthetic system because of the easy way to keep the short distance between the electron donor and acceptor. The various researches for the artificial photosynthesis with covalently linked donor-acceptor systems exist. In this work we established the self-assembled zinc porphyrin and fullerence[C60]system to build up the supramolecules containing them and to achieve the photoinduced electron transfer reactions with high efficiency and the long-lived charge separated state like a photosynthetic reaction center. In these supramolecular systems, efficient charge separation was confirmed by the time-resolved fluorescence measurements and by the fs-ps transient absorption methods. The lifetimes of charge-separated states were determined by the ns transient spectra in near IR region.
The pyridine and imodazole moieties were introduced on C_<60> to construct the supramolecular systems via coordination bonds between zinc porphyrin. In the case of imodazole, we obtained the higher equilibrium constant in the formation of the supramolecule and the high efficiency of the charge separation. The higher equilibrium constant for axial coordination was obtained at low temperature. This means that the more efficient charge separation occurred at the low temperature.
On the other hand, we found that the supramolecular systems in rotaxanes containing C_<60> and porphyrin. In these systems, C_<60> has a ring to catch the axel, which has porphyrin as a stopper. By the time-resolved fluorescence and transient absorption measurements, we found the efficient intra-rotaxane charge separation and long-lived charge separated state in these rotaxane. Interestingly, we found the size dependency of the charge separation type ; the change separation starts from the excited singlet state in the small rotaxane, however, it starts from the excited triplet state in the large one.
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