| Co-Investigator(Kenkyū-buntansha) |
UNNO Masashi Tohoku University, Institute for Chemical Reaction Science, Research Associate, 反応化学研究所, 助手 (50255428)
OHBA Yasunori Tohoku University, Institute for Chemical Reaction Science, Associate Professor, 反応化学研究所, 助教授 (10176985)
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| Research Abstract |
Collaborative studies were made by use of two techniques, electron paramagnetic resonance(EPR) and vibrational (Raman) spectroscopy, giving the following results.
For EPR, we collaborated with four laboratories, Prof.Moebius's at Free University of Berlin, Prof.Corvaja's at Padova University in Italy, Prof.Levanon's at Hebrew University of Jerusalem, and Prof.Kothe's at Freiburg University in Germany, where we made the experiments and discussion. For Raman, Dr.Unno visited Prof.Champion's lab. at Northeastern University of Boston and ran experiments for two weeks.
1. In a system of metallo(Zn and Mg) porphyrin-nitroxide radical, we observed excited doublet and quartet states for the first time by EPR techniques, which are separated nicely by means of high frequency (95 GHz) EPR.
2. EPR signals of the excited triplet states were observed for the first time in solution using metallo-porphyrins and -phthalocyanines up to +90℃. From the spectral simulation, averaging over the Jahn-Teller split states and molecular motions were analyzed , which indicates that this method is very useful for analyses of excited triplet properties in solution.
3. Two dimensional (2D) pulsed EPR techniques were developed to determine spin multiplicity of the excited multiplet states and applied to studies in systems of bisradical linked fullerene. On excitation the excited quintet states were observed and definitely assigned for the first time and the electronic structures were analyzed.
4. The resonance Raman investigation was made for oxygenated cytochrome P450 and a structural marker band was successfully assigned at the active site. The observation of the Fe-O-O bending mode reveals structural specificity of the enzyme.
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