醛基不饱和卡宾存在寿命的理论研究

Theoretical studies on the exist life of alkanoyl-unsaturated-carbene HCO-CHC∶

采用量子化学中的从头计算方法 ,在B3LYP/ 6 - 31G 水平上研究了醛基不饱和卡宾HCO—CHC∶重排成醛基乙炔的反应机理 .全优化得到了HCO—CHC∶的两种稳定构型以及对应的过渡态和产物的构型 ,并计算得到了各种构型的振动频率 .在振动频率计算结果的基础上 ,采用过渡态理论计算了活化能最小的重排反应的动力学性质 ,然后根据得到的反应速率常数 ,计算了不同温度下HCO—CHC∶的半衰期 .结果表明 ,HCO—CHC∶的半衰期很短 ,室温下只有 10 -13s左右 .

Structures and isomerizations of alkanoyl-unsaturated-carbene HCO-CHC∶have been examined in detail by ab initio method at B3LYP/6-31G** level. HCO-CHC∶ has two structures, one is trans -isomer, the other is cis -isomer. The two isomers rearrange to Alkanoylacetylene very easy. The rates of the reactions of H-isomerizations of HCO-CHC∶ to HCO-C≡CH have been calculated, and the half life of trans -HCO-CHC∶ and cis - HCO-CHC∶ have been obtained using the rates.