H2O, H2S与双卤分子间相互作用的电子密度拓扑研究

运用量子化学微扰理论MP2和密度泛函B3LYP方法, 采用6-311＋＋G(d,p)基组, 对H₂O, H₂S与双卤分子XY (XY＝F₂, Cl₂, Br₂, ClF, BrF, BrCl)形成的卤键复合物进行构型全优化, 并计算得到了这些体系的分子间相互作用能. 利用电子密度拓扑分析方法对卤键复合物的拓扑性质进行了分析研究, 探讨了该类分子间卤键的作用本质. 结果表明, 形成卤键后, 作为电子受体的双卤分子X—Y键长增长, 振动频率减小. 复合物体系中的卤键介于共价键与离子键之间, 偏于静电作用成分为主.

Topological Studies of Electron Density on the Interaction between H2O or H2S and Dihalogen Molecules

The full geometry optimizations for the halogen-bonded systems, H₂O(H₂S)…XY (XY＝F₂, Cl₂, Br₂, ClF, BrF, BrCl), were carried out using MP2 and B3LYP methods at 6-311＋＋G(d,p) levels. The interaction energies of the halogen-bonded complexes were calculated. The topological properties of chemical bonds were investigated by the topological analysis of electron density. The nature of halogen bond was investigated. The outcome indicated that the formation of halogen bond resulted in an elongation of X—Y bond, which was accompanied by red-shift of vibrational frequencies of the bond. This kind of halogen bond is between covalent and ionic interactions, with the static interaction being dominant.