金属碳、卡宾阳离子[M—X]^+(M=Au,Ag,Cu;X=C,CH2)与甲烷反应机制研究

Mechanism Research of Reactions of Metal Carbides and Carbenes Cation[M—X]^+( M=Au,Ag,Cu;X=C,CH_2) with Methane

在CCSD(T)-REL//B2GP-PLYP水平下构建[Au(CH_2)]^+与甲烷反应的可靠反应势能面,分析了C—H键活化过程中的几何结构变化情况;对反应IRC路径上关键点进行自然键轨道(NBO)电荷和分子轨道分析,从理论上推定该氢转移过程属于氢负离子(H^-)转移.对[M—X]+(M=Au,Ag,Cu;X=C,CH_2)与甲烷反应进行对比,分析了甲烷作为氢供体反应过程的内在影响因素.M—X键能和反应活性中心C上直接参与反应的低能轨道对反应活性均起重要作用,两者协同调控微观反应机制.

In this article, the reaction mechanism of the cation [ Au（ C H2 ） ]＋ and methane was investigated at the CCSD（T）-REL//B2GP-PLYP level of theory initially. A detailed analysis of geometric structure changes during the C--H bond activation was1 given. As a major result, based on natural bond orbital（NBO） charge and molecular orbital analysis, a hydride transfer mechanistic scenario from methane to [ Au （ CH2 ） ] ＋ was identified unambiguously. Methane activation has been identified among its reaction with [ M--X ] ＋（ M--Au, Ag, Cu ; X = C, CH2 ）. Analysis for the inherent factors during the reaction of methane as a hydrogen donor is given. The M--X bond energy and the low-lying vacant orbital directly involved in the reaction of the active center C play an important role on the reaction activity, and both mediated microscopic mechanism. This study may provide important guidance for the rational design of catalysts.