二氯卡宾与异氰酸反应机理的量子化学研究

Theoretical study of the reaction mechanism for the carbon dichlorine radical with isocyanic acid

采用密度泛函理论B3LYP方法研究了单、三重态CCl_2与HNCO的反应机理,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,并用G3方法计算了各个驻点的单点能.计算结果表明:单重态的CCl_2与HNCO的反应有抽提氧、插入N-H键、抽提亚氨基的路径,三重态的CCl_2与HNCO发生抽提氢的反应,其中单重态反应通道HNCO+CCl_2→IM3→TS2→P2(C_2Cl_2ONH)反应能垒最低,为主反应通道.

The reaction mechanism of singlet and triplet CCl2 with HNCO 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/6-311H＋＋G＊＊ level. Intermediates and transition states were confirmed by the results of vibration analysis and the IRC calculation. The energies of stationary point were calculated at G3 level. The results indicate that the reaction of singlet CCl2 with HNCO have O-atom abstraction channel, insert N--H channel, NH abstraction channel, and triplet CCl2 with HNCO has H-atom abstraction channel, among which singlet reaction HNCO＋CCI2→IM3→TS2→P2 （C2Cl2ONH） was the main pathway with the lowest activation energy.