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Photochemistry of Physiologically Active Substances : Study by Time-Resolved Raman Spectroscopy

生理活性物质的光化学：时间分辨拉曼光谱研究

基本信息

批准号：
09440205
负责人：
TAKAHASHI Hiroaki
金额：
$ 8.26万
依托单位：
Waseda University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 2000
项目状态：
已结题

项目摘要

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.

黄素单甘肽（FMN）的光化学：测定了FMN的T_1态、阴离子自由基和半醌自由基的时间分辨吸收光谱和时间分辨拉曼光谱。结果表明，半醌自由基是从T_1态经阴离子自由基生成的。测量了卟啉及其衍生物的光化学：时间分辨拉曼光谱和吸收光谱。发现8-MOP的T_1态产率比PS和5-MOP低得多。这很可能与8-MOP的光过敏和光毒性远小于PS和5-MOP有关。胆红素的光化学：用308 nm光照射胆红素，在450和415 nm处观察到瞬态吸收带。在450 nm处的瞬态带具有260 ns的寿命，可以被指定为T_1态，因为它被氧猝灭。烟酰胺腺嘌呤二核苷酸（nicotinamideadenine dinucleotide，NADH）的光化学反应：该化合物的光氧化反应分为三个步骤：（1）通过发射电子产生阳离子自由基NADH^+;（2）通过质子转移产生中性自由基NAD ^+。(3)邻硝基苄基化合物的光化学反应：这种光反应是由邻硝基从亚甲基上夺取一个氢原子而引发的，从而生成酸-硝酸。在极性溶剂中，醋硝酸解离成醋硝阴离子和质子，质子与2-吡啶基或4-硝基结合产生邻醌或对醋硝酸。