噻吩光解反应机理的理论研究  

Theoretical Investigations on the Photolysis of Thiophene

作　　者：张文雨[1] 丁万见[1] 刘若庄[1] 

机构地区：[1]北京师范大学化学学院,北京100875

出　　处：《化学学报》2008年第5期497-504,共8页Acta Chimica Sinica

基　　金：国家自然科学基金(Nos.20403003;20472011;20233020);国家重点基础研究发展计划(No.2004CB719903)资助项目

摘　　要：使用密度泛函理论(DFT)中的B3LYP方法,采用6-31G**和6-31++G**基组,对噻吩的光解反应进行了理论研究.对照实验结果,我们研究了五个光解通道,包括生成C4H4+S,C2H2+C2H2S和CS+C3H4的三个闭壳层分子解离通道与生成HCS+C3H3和HS+C4H3的自由基解离通道.各个可能的反应通道的产物碎片的具体形式得到了确认.研究发现在基态生成C2H2+C2H2S和在最低三态生成C4H4+S的反应从能量上考虑最为有利,而实验上观测到的主要产物C2H2+C2H2S主要是在基态上产生的.通过对比实验结果与计算结果,我们认为噻吩光解反应机理与所用激发光波长有关.Density functional theory （B3LYP） along with 6-31G＊＊ and 6-31＋＋G＊＊ basis sets was employed to investigate the photodissociation reactions of thiophene. According to the experiment results, five photolysis channels have been examined, including three closed-shell molecular channels yielding C4H4＋S, C2H2＋C2H2S, and CS＋C3H4, and two radical channels yielding HCS＋-C3H3 and HS＋C4H3. The most probable isomers of the product fragments were determined. It was found that the reaction yielding C4H4＋S was the most energetically favorable in the triplet state and c-CnH4S→C2H2＋C2H2S was preferential in the ground state. The calculation results show that C2H2q-C2H2S, which were found to be the major products, were formed mainly in the ground state. By comparison of the computational results with the experimental findings, it can be concluded that the photodissociation mechanism of thiophene is dependent on the wave length.

关 键 词：噻吩 光解 反应机理 B3LYP 

分 类 号：O643.12[理学—物理化学] O621.2[理学—化学]