分子内结构环境对解离能的影响

为了理解化学键的这一结构效应, 本文对具有相同化学键而分子内结构环境不同的系列分子进行了计算研究, 讨论了化学键结构环境对解离能的影响.

Effect of Intramolecular Structural Environment on Bond Dissociation Energies

The density functional calculations were used to explore the dissociation energies of N(CH3)4]+ and P(CH3)4]+ and their derivatives from substitution of H for CH3. The results show that the dissociation energies of C—N and C—P bonds gradually increase as the number of hydrogen atoms bonded to N or P increases in the derivatives, showing a remarkable effect of the intramolecular structural environment on the dissociation of the bonds. This dependence of bond dissociation energies on the local structural environment can be ascribed to the hyperconjugation interactions between the C—H bond and lone single electron of N or P. On the basis of NBO analyses, the bonding properties of dissociated fragments and their effects on dissociation energies were discussed.