偏二甲基肼亲核性的量子化学研究

The Quantum Chemical Investigation on the Nucleophilicity of UDMH

为了从分子水平上了解偏二甲基肼(UDMH)中-NH2和-N(CH3)2的亲核性差异,采用RHF、DFT/B3LYP、MP2及半经验量子化学方法对UDMH进行了几何构型全优化,并将计算的平衡几何结构参数与实验值进行了对比。在B3LYP/6-311G计算所得的平衡几何构型基础上,分别根据静电势和分子轨道计算研究了分子中-NH2和-N(CH3)2的亲核性,并与偏二甲基肼和卤代烃反应的实验结果进行了对比分析。结果表明,分子轨道计算的亲核性结果与实验结果一致,表明-N(CH)比-NH具有更强的亲核性。

In order to study the nucleophilicity difference between- NH2 and --N （CH3）2 of unsymmetrical dimethylhydrazine, full geometrical optimizations of UDMH have been carried out by RHF, DFT/B3LYP, MP2 and semiempirical methods. The predicted structure parameters are compared to the experimental ones. On the basis of equilibrated geometrical structure obtained by B3LYP/6-311G method, the nucleophilicity of --N （CH3）2 and --NH2 groups are investigated by electrostatic potential and MO calculations. The calculated nucleophilicities are compared to the experimental results of the reaction of UDMH with halohydrocarbon. The calculated results of nucleophilicity by MO are in agreement with the experimental results, showing that the nucleophilicity of --N（CH3）2 is stronger than that of--NH2.