锗烯与异硫氰酸反应机理的量子化学研究

采用密度泛函理论B3LYP方法研究了GeH2自由基与HNCS的反应机理,并在B3LYP/6-311++G**水平上对反应物,中间体,过渡态进行了全几何参数优化,通过频率分析和IRC确定中间体和过渡态。为了得到更精确的能量值,用QCISD(T)/6-311++G**方法计算了各个驻点的单点能,计算结果表明单重态的锗烯与异硫氰酸的反应有抽提硫、插入N-H键、抽提亚氨基的路径,而经由三元环中间体的抽提硫反应GeH2+HNCS→IM3→TS2→IM4→TS3→IM5→GeH2S+HNC(P1),反应能垒最低,为主反应通道,甲锗硫醛和异氰氢酸为主产物。锗烯经由四元环中间体抽提硫的反应为竞争反应通道。

Theoretical study of the reaction mechanism for the germene radical with isothiocyanic acid

The reaction mechanism of germene radical with isothiocyanic acid has been investigated by B3LYP method of density function theory:The geometries and harmonic of reactants,intermediates,transition states and products have been calculated at the B3LYP/6-311++G**level.To obtain more precise energy result,stationary point energies were calculated at QCISD(T)/6-311++G**//B3LYP/6-311++G**level.Intermediates and transition states were confirmed by the results of vibration analysis and the IRC calculation.The results indicate that the reaction of singlet state germene radical with isothiocyanic acid has S-atom abstraction channel,insert N-H channel,NH abstraction channel,respectively.The pathway GeH2+HNCS→IM3 →TS2→IM4→TS3→IM5→GeH2S+HNC(P1)was the main one with the lowest activation energy,and the main products were GeH2S and HNC.The pathways of S-atom abstraction with the four-membered ring intermediate were the competitive channel.