CuI/BtH催化苯硫酚与对甲氧基溴苯C–S偶联合成(4-甲氧基)(苯基)硫醚反应机理理论研究  

The mechanism for C–S coupling reaction of benzenethiol and 1-bromo-4-methoxybenzene to synthesize(4-methoxyphenyl)(phenyl)sulfane catalyzed by CuI/BtH

作　　者：王刚[1] 白坤坤 李来才[1] 田安民[2] 

机构地区：[1]四川师范大学化学与材料科学学院,成都610066 [2]四川大学化学学院,成都610064

出　　处：《中国科学：化学》2014年第3期334-344,共11页SCIENTIA SINICA Chimica

基　　金：四川省高校重点实验室开放课题(KFKT201204);四川省教育厅重点项目

摘　　要：采用密度泛函理论(DFT)中的B3LYP方法对CuI/BtH催化苯硫酚与对甲氧基溴苯C–S偶联合成(4-甲氧基)(苯基)硫醚反应机理进行了理论研究.在6-31+G(d)基组水平上,全参数优化了气相条件和N,N-二甲基甲酰胺(DMF)溶剂化条件下反应机理中所有反应物、过渡态、中间体和产物构型,对优化后各化合物的构型在B3LYP/6-311++G(d,p)基组下进行了单点能计算和零点能矫正,通过能量和振动频率分析以及内禀反应坐标(IRC)计算证实了中间体和过渡态的合理性.并且在优化计算相同基组水平上,应用自然键轨道(NBO)理论和分子中的原子(AIM)理论分析了复合物的成键特征和轨道间相互作用.在CuI单独催化此反应的机理中,计算得到一条反应路径,控制步骤所需活化能是180.49 kJ/mol(sol).而当CuI/BtH共同催化反应时,计算得到两条反应通道IA和IB,其中IA为最优反应通道,控制步骤所需活化能为101.77kJ/mol(sol);IB反应通道控制步骤活化能为143.78 kJ/mol(sol).配体苯并三唑(BtH)加入反应有效地降低了反应控制步骤所需活化能,同时有利于产物和催化剂的分离,这与实验所得结论一致.The mechanism of CuI/BtH catalyzed C-S coupling reaction of benzenethiol and 1-bromo-4- methoxybenzene to synthesize （4-methoxyphenyl）（phenyl）sulfane has been investigated by density functional theory （DFT）. The geometries of reactants, intermediates, transition states, and products were optimized in both gaseous phase and solvent N,N-dimethyl formamide （DMF） at the B3LYP/6-31＋G（d） level. The single point energies and zero point energy correction were calculated for the optimized configuration of each compound at B3LYP/6-311＋ ＋G（d,p） level. Vibration analysis, energy calculation and IRC calculation proved the authenticities of the intermediates and the transition states. Atoms in molecules （AIM） and nature bond orbital （NBO） theories were used to discuss the bond nature and orbital interactions at the same of optimization calculation level. In CuI catalytic mechanism, there is one pathway, the rate-determining step activation energy of which is 180.49 kJ/mol in solution. In CuI/BtH catalytic mechanism, there are two possible pathways： IA is the optimal pathway and the activation energy of rate-determining step is 101.77 kJ/mol; the activation energy of rate-determining step in IB is 143.78 kJ/mol （sol）. Since the ligand 1H-benzo[d][1,2,3]triazole （BTH） can reduce the activation energy of rate-determining step and the dissociation energy of catalyst, meanwhile, it is favorable for the separation of products and catalyst, which is in accordance with experimental results.

关 键 词：苯硫酚 对甲氧基溴苯 反应机理 密度泛函理论 活化能 

分 类 号：O643.12[理学—物理化学] O621.251[理学—化学]