Photochemical Hydrogen Abstraction and Electron Transfer Reactions of Tetrachlorobenzoquinone with Pyrimidine Nucleobases  

四氯苯醌与嘧啶类核酸碱基的光化学氢抽取和电子转移反应

作　　者：刘坤辉[1] 吴丽丹[1] 邹笑然[1] 杨文[1] 杜谦[1] 苏红梅[1] 

机构地区：[1]中国科学院化学研究所分子反应动力学国家重点实验室、北京分子科学国家实验室,北京100190

出　　处：《Chinese Journal of Chemical Physics》2011年第5期580-585,I0004,共7页化学物理学报（英文）

基　　金：This work was supported by the National Natural Science Foundation of China （No.20903104, No.2107320L and No.20733005） and the Chinese Academy of Sciences.

摘　　要：Pentachlorophenol, a widespread environmental pollutant that is possibly carcinogenic to humans, is metabolically oxidized to tetrachloroquinone （TCBQ） which can result in DNA damage. We have investigated the photochemical reaction dynamics of TCBQ with two pyrimidine type nucleobases （thymine and uracil） upon UVA （355 ran） excitation using the technique of nanosecond time-resolved laser flash photolysis. It has been found that 355 nm excitation populates TCBQ molecules to their triplet state 3TCBQ＊, which are highly reactive towards thymine or uracil and undergo two parallel reactions, the hydrogen abstraction and electron transfer, leading to the observed photoproducts of TCBQH. and TCBQ.- in transient absorption spectra. The concomitantly produced nucleobase radicals and radical cations are expected to induce a series of oxidative or strand cleavage damage to DNA afterwards. By characterizing the photochemical hydrogen abstraction and electron transfer reactions, our results provide potentially important molecular reaction mechanisms for understanding the carcinogenic effects of pentachlorophenol and its metabolites TCBQ.

关 键 词：Tetrachlorobenzoquinone THYMINE URACIL Triplet state Hydrogen abstraction Electron transfer Laser flash photolysis 

分 类 号：O[理学]