PdCl2催化芳基硼酸与溴代芳烃Suzuki-Miyaura偶联反应的机理研究

:采用密度泛函理论(DFT)中的M06方法, 以二甲基甲酰胺(DMF)溶剂, 研究了无催化剂、PdCl2为催化剂催化芳基硼酸与溴代芳烃的交叉偶联反应的反应机理. 使用6-311+G*基组 (Pd采用赝势基组LanL2DZ) 对芳基硼酸与溴代芳烃Suzuki-Miyaura偶联反应过程中所有反应物、中间体、过渡态和产物的几何构型进行了优化, 同时进行了频率计算, 各过渡态都有唯一虚频, 确认了中间体和过渡态的合理性; 通过自然键轨道(NBO)理论和AIM理论分析了分子轨道间的相互作用. 结果发现: 在没有催化剂的条件下, Suzuki-Miyaura偶联反应形成的反应速控步骤活化能为49.70 kcal/mol, 在PdCl2催化作用下, 反应速控步骤活化能为31.08 kcal/mol, 比较研究结果, PdCl2能有效催化该反应的进行, 我们的研究结果与实验结果相吻合.

Research on the mechanism of Suzuki-Miyaura coupling reaction of aryl boric acid with aryl bromide Catalyzed by PdCl2

Using the density functional theory (DFT) M06 method, we studied the reaction mechanism of the cross coupling reaction of aryl boric acid with aryl bromide catalyzed by PdCl2 and no catalyst. Under the basis set level of 6-311+G(d,p) (Pd using the pseudo potential basis set of LanL2DZ), we optimized the configuration of all the reactants, transition state, intermediates and products of Suzuki-Miyaura coupling reaction with aryl boronic acid and aryl bromide. Meanwhile, we calculated the frequency and found out that all the transient state had the only imaginary frequency; moreover, we confirmed the rationality of intermediates and transient state. We analyzed the interaction among molecular orbits via NBO and AIM. The results showed that the Suzuki Miyaura coupling reaction rate-determing energy of no catalyst is 49.70 kcal/mol the rate-determing energy is 31.08 kcal/mol with PdCl2. Comparing the results, PdCl2 can effectively catalyze the reaction. Our results are in accordance with the experimental results.