2001 Fiscal Year Final Research Report Summary
Photochemistry of Physiologically Active Substances : Study by Time-Resolved Raman Spectroscopy
| Project/Area Number |
09440205
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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 |
Physical chemistry
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| Research Institution | Waseda University |
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Principal Investigator |
TAKAHASHI Hiroaki Waseda University, School of Science and Engineering, Professor, 理工学部, 教授 (40063622)
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| Co-Investigator(Kenkyū-buntansha) |
TACHIKAWA Tomonori Waseda University, School of Science and Engineering, Assistant Professor, 理工学部, 講師 (00267410)
YUZAWA Tetsuro Waseda University, School of Science and Engineering, Assistant Professor, 理工学部, 講師 (40261200)
ITOH Koichi Waseda University, School of Science and Engineering, Professor, 理工学部, 教授 (40008503)
SAKAI Makoto Waseda University, School of Science and Engineering, research Associate, 理工学部, 助手 (60298172)
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| Project Period (FY) |
1997 – 2000
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| Keywords | Physiologically active substances / Photochemistry / Picosecond time-resolved Raman Spectroscopy |
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| Research Abstract |
Photochemistry of flavin mononucleotide (FMN) : Time-resolved absorption and time-resolved Raman spectra of the T_1 state, anion radical and semiquinone radical of FMN were measured. It was shown that semiquinone radical was generated from the T_1 state via the anion radical.
Photochemistry of psoralen and its derivatives : Time-resolved Raman and absorption spectra of these compounds were measured. It was found that the yield of theT_1 state of 8-MOP is much too low compared to those of PS and 5-MOP. This is most probably related to the fact that the photoallergy and phototoxicity of 8-MOP is much smaller than those of PS and 5-MOP.
Photochemistry of bilirubin : Transient absorption bands were observed at 450 and 415 nm by *adiation of bilirubin with 308 nm light. The transient band at 450 nm having the lifetime of 260 ns can be assigned to the T_1, state, because it is quenched by oxygen. The identity of the transient exhibiting 415 nm band and having the lifetime of 17μs is not clarified as yet.
Photochemistry of nicotinamideadenine dinucleotide (NADH) : The photooxydation reaction of this compound proceeds with the following three steps : (1) generation of cation radical NADH^+ by ejection of an electron. (2) generation of neutral radical NAD by proton transfer. (3) generation of NAD^+ by an electron ejection.
Photochemistry of ortho-nitrobenzyl compounds : This photoreaction is initiated with the abstraction of a hydrogen atom by the ortho-nitro group from the methylene group to generate aci-nitroacid. In polar solvents the acinitro acid dissociates into the acinitro anion and a proton which combines to the 2-pyridyl group or 4-nitro group to yield ortho-quinoid or para-acinitro acid.
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