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Photochemical Hydrogen Abstraction and Electron Transfer Reactions of Tetrachlorobenzoquinone with Pyrimidine Nucleobases
Kun-hui Liu,Li-dan Wu,Xiao-ran Zou,Wen Yang,Qian Du,Hong-mei Su*
Author NameAffiliationE-mail
Kun-hui Liu State Key Laboratory of Molecular Reaction Dynamics, Beijing National Laboratory for Molecular Sci-ences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China  
Li-dan Wu State Key Laboratory of Molecular Reaction Dynamics, Beijing National Laboratory for Molecular Sci-ences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China  
Xiao-ran Zou State Key Laboratory of Molecular Reaction Dynamics, Beijing National Laboratory for Molecular Sci-ences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China  
Wen Yang State Key Laboratory of Molecular Reaction Dynamics, Beijing National Laboratory for Molecular Sci-ences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China  
Qian Du State Key Laboratory of Molecular Reaction Dynamics, Beijing National Laboratory for Molecular Sci-ences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China  
Hong-mei Su* State Key Laboratory of Molecular Reaction Dynamics, Beijing National Laboratory for Molecular Sci-ences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China hongmei@iccas.ac.cn 
Abstract:
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 nm) 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.
Key words:  Tetrachlorobenzoquinone, Thymine, Uracil, Triplet state, Hydrogen abstrac-tion, Electron transfer, Laser flash photolysis
FundProject:
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
刘坤辉,吴丽丹,邹笑然,杨文,杜谦,苏红梅*
摘要:
采用纳秒时间分辨的激光闪光光解实验技术,研究了四氯苯醌(TCBQ)分子与两种嘧啶核酸碱基(胸腺嘧啶和尿嘧啶)分子在355nm激发下的光化学反应动力学. 355 nm将TCBQ分子布居到激发三重态3TCBQ*,高反应活性的3TCBQ*与碱基分子发生两个平行的反应,氢抽取反应和电子转移反应,分别对应生成瞬态光谱上观测到的两个光反应产物TCBQH·和TCBQ·-. 这两个反应同时生成的碱基自由基和碱基阳
关键词:  四氯苯醌,胸腺嘧啶和尿嘧啶,三重态,氢抽取和电子转移,激光闪光光解
DOI:10.1088/1674-0068/24/05/580-585
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