硝酰氯和顺/反亚硝酸氯及其互变异构反应的理论研究

Theoretical studies on nitryl chloride, cis-and trans-chlorine nitrite and their tautomerisms

用密度泛函理论 (DFT)的B3LYP方法和 6-3 1 1 +G( 3df)基组 ,计算了气态下硝酰氯和顺 /反亚硝酸氯的几何构型、电子结构、红外光谱以及热力学性质 ,并讨论了它们的互变异构反应 ,分析了过渡态的结构 .结果表明 ,B3LYP/6-3 1 1 +G( 3df)计算得到的结果与实验值及CCSD(T)方法计算结果吻合 ,且更适应于研究反应机理 .ClNO2 转变为cis-ClONO的过渡态 (TS1 )偏离平面构型 ;cis-ClONO和trans-ClONO互变反应的过渡态 (TS2 )属于内旋转位垒 ;高水平计算表明不存在由ClNO2 直接转变为trans-ClONO的过渡态 ,而是得到了一个十分接近异裂产物的二级马鞍点 ( 2SP) .根据得到的热力学函数计算了气态时各温度下互变异构反应的平衡常数 .

The geometries, electronic structures, infrared spectras and thermodynamic properties of nitryl chloride, cis - and trans -chlorine nitrite were investigated by density functional theory at B3LYP/6-311+G(3 df ) level. The results were in good agreement with experimental values and CCSD(T) results. The tautomerisms among the three isomers were discussed. It has shown that the transition state TS1 is not a planar structure, and cis -ClONO undergoes an intramolecular rotation barrier(TS2) to form trans -ClONO. High level calculations indicate ClNO2 can not transform to trans -ClONO directly, but a planar second-order saddle point (2SP) with a structure very close to isolated NO 2 + and Cl - has been obtained. The balance constants of tautomerism reactions with the temperature ranging from 100 K to 1 000 K have been calculated.