氯代乙炔HCCCl与卤代乙炔HCCR(R=Cl,Br)分子间相互作用的理论研究

Theoretical study on intermolecular interactions between HCCCl and HCCR (R=Cl,Br)

在MP2/6-311++G(d,p)水平上,对氯代乙炔HCCCl与卤代乙炔HCCR(R=Cl,Br)分子间所有可能存在的复合物进行了全自由度能量梯度优化,通过相同水平上的频率验证分析发现了3类稳定的分子间相互作用模式:卤键型(I)、π-卤键型(II)和π-氢键型(III).其中,π-氢键是最强的分子间相互作用模式.SAPT(Symmetry Adapted Perturbation Theory)能量分解结果表明:在构型I复合物的分子间的相互作用中,色散能占主导地位;在构型II复合物中,诱导作用是最重要的吸引作用;而在构型III复合物中,静电能和色散能大小相当,两者一起决定了复合物相互作用能的大小.

Ab initio molecular orbital calculations including MP2 correlation energy was employed to optimize the geometries of the intermolecular interactions formed by HCCCl with HCCR （R= Cl, Br） at 6-311 ＋＋G （d, p） level. Three types of stable intermolecular interactions were observed ： halogen bonded, π-halogen bonded and π-hydrogen bonded, the w-hydrogen bonded structure is the most stable one for a given HCCR. An SAPT （the symmetry adapted perturbation theory） interaction energy decomposition analysis reveals that the dispersion force is found to be the main origin of the halogen bonded interactions, and the π-halogen bonded interactions are dominantly inductive in nature; while both the electrostatic and dispersion energy governs the π-hydrogen bonded interactions.