C6H5—H…X分子间氢键的理论计算

利用密度泛函理论B3LYP方法, 在6-311+G(3df,2p)水平上对C6H5—H…X型分子间氢键进行了几何构型优化、氢键相互作用能、电子密度分布等计算. 其中C6H6为质子供体, HCOH、H2O、NH3、CH2NH和HCN为质子受体. 从电荷布居分析、自然键轨道等角度详细地讨论了C6H5—H…X 体系中, 共轭π键、O和N的不同键型结构对氢键形成的影响以及孤电子对与C—H 反键轨道之间的相互作用(n→σ*)等.

Theoretical Calculation on the C6H5-H…X Hydrogen-bonded Complexes

The optimized structures and binding energies of a series of C6H5—H…X hydrogen-bonded complexes involving H2O, HCOH, NH3, CH2NH and HCN as proton acceptors were determined at B3LYP/6-311+G(3df, 2p) level. The calculated results showed that the binding energies of C6H5—H…X complexes were dependent on the nature of the proton-accepting groups. The contributions of π-bond, double-bond, triple-bond to the hydrogen bonds, and the interaction energies between lone-pair electrons and the C—H antibond were discussed in detail by natural population analysis (NPA) and natural bond orbital analysis (NBO).