2001 Fiscal Year Final Research Report Summary
Studies on photo-driven logic molecular devices with fast response
| Project/Area Number |
12640556
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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 |
機能・物性・材料
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| Research Institution | Osaka University |
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Principal Investigator |
NOZAKI Koichi Osaka Univ., Graduate School of Science, Chemistry Department, Assistant Professor, 大学院・理学研究科, 助手 (20212128)
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| Project Period (FY) |
2000 – 2001
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| Keywords | electron transfer / mixed-valence complex / ruthenium complex / Osmium complex / DNA probe / light switching / charge transfer memory |
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| Research Abstract |
1. Charge-transfer type logic devices based on mixed-valence complexes
When Ru(II)-Os(III) mixed-valence complex bridged with tetrapyridophenazine was photoirradiated, it was observed that electron transfer from MLCT state of Ru(II) moiety to Os(III) moiety occurs with time constant of 20 ps and with high efficiency (Ф〜1). The lifetime of the resultant product state, Ru(III)-Os(II) mixed-valence isomer state, was longer than 100 ns. Since two pseudo-stable states, Ru(II)-Os(III) and Ru(III)-Os(II), observed in this complex can be regarded as logical state, '0' and '1', respectively, we thought that this complex would work as photo-driving flip-flop molecule with very fast response (〜100GHz). However, the irradiation of '1' state, i.e., Ru(III)-Os(II), did not give '0' state, efficiently. The quantum mechanical calculation of this molecule indicated that two MLCT states, i.e., (^3CT)Ru(II)-Os(III) and Ru(III)-(^3CT)Os(II), so strongly interact each other that the barrier between the two MLCT states was not high enough to allow them to be localized.
2. The mechanism of light-switching of DNA molecular probe
To clarify the mechanism of light-switching in Ru(II) dppz (dppz=dipyridophenazine) which is known to be an excellent DNA probe, the emission properties were measured for Ru(II) of various dppz derivatives. It is found out that only 100meV difference in solvation energy for between two MLCT states can switch the emission peak energy. Such sharp switching is mainly responsible for the unusually weak electronic interaction between two MLCT states (〜65 meV).
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Research Products
(8 results)
