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对金属元素Au采用LanL2DZ基组,对非金属元素C,H,O,Cl采用6-31G*和6-311++G**基组,用密度泛函理论的B3LYP、B3PW91、UB3LYP方法和二阶微扰理论MP2方法研究了不同氧化态的金催化剂催化2-炔丙基苯酮与苯炔环化反应的机理.结果表明:在AuCl和AuCl3的作用下,反应均能通过[4+2]和[3+2]途径生成产物.但在AuCl催化下,[4+2]反应途径比[3+2]反应途径具有更低的活化自由能,反应主要通过[4+2]途径进行;而在AuCl3催化下,[4+2]反应途径与[3+2]反应途径的活化自由能相近,反应通过两条途径竞争生成产物.比较AuCl和AuCl3的催化效果发现,不同氧化态的金催化剂改变了反应的机理,该反应的活化自由能在AuCl作用下比在AuCl3作用下低11.18kJ·mol-1.对于该反应,AuCl表现出了更好的催化活性.这些计算结果和实验现象相吻合.
The LanL2DZ basis set is adopted for the metal element Au and the 6-31G * and 6-311 ++ G ** basis sets are used for the non-metal elements C, H, O and Cl. The density functional theory B3LYP, B3PW91 and UB3LYP methods are used The second-order perturbation theory (MP2) method was used to study the cyclization reaction of 2-propargylbenzophenone and benzyne with gold catalysts of different oxidation states. The results showed that the reaction can be catalyzed by AuCl and AuCl3, 2] and [3 + 2], but the [4 + 2] reaction pathway has a lower activation free energy than the [3 + 2] pathway under AuCl catalysis. , While the activation energy of [4 + 2] and [3 + 2] reaction pathways are similar under the AuCl3 catalysis, and the products compete with each other through two routes of production. Comparing the catalytic effects of AuCl and AuCl3, The gold catalyst changed the reaction mechanism, and the activation free energy of the reaction was 11.18 kJ · mol-1 lower than that of AuCl3 under the action of AuCl. For these reactions, AuCl showed better catalytic activity The experimental phenomenon is consistent.