BeH2与HX(X=F,Cl, Br,I)形成的二氢键复合物的结构特征与本质

对BeH2与HX(X=F, Cl, Br, I)形成的二氢键复合物的结构特征及本质进行了探讨. 在MP2/6-311++G(3d,3p)水平优化、频率验证, 得到复合物的分子结构, 用分子间距离及电子密度拓扑理论确认BeH2与卤化氢已形成了二氢键型复合物. 在MP2/6-311++G(3d, 3p)水平下进行基函数重叠误差(BSSE)校正后的结合能在-14.468 kJ·mol-1到-5.464 kJ·mol-1之间.用对称匹配微扰理论(SAPT)对复合物的结合能进行分解, 结果表明, BeH2…HX二氢键复合物中静电能对总吸引能的贡献都是最主要的, 但交换排斥能、诱导能、色散能对总结合能的贡献也很重要. 从BeH2…HF到BeH2…HI, 诱导能对总吸引能的贡献从37.8%逐渐减小到24.0%. 而色散能对总吸引能的贡献从BeH2…HF体系中的16.0%逐渐增加到BeH2…HI体系中的33.8%.

Nature and Structural Property of Dihydrogen-bond Complexes of BeH2 with Hydrogen Halides

The intermolecular complexes of BeH2 with hydrogen halides (HX(X=F, Cl, Br, I)) were examined using ab initio calculations performed at the second-order Moller-Plesset perturbation approximation with the 6-311++G(3d,3p) basis set. Dihydrogen-bonds were formed in complexes of BeH2 with hydrogen halides based on the judgement from the geometrical criteria. The characteristics of the bond critical points, the electron densities and their Laplacians, also confirmed this conclusion. The calculated binding energies of complexes of BeH2 with hydrogen halides usingMP2/6-311++G(3d, 3p) methods, corrected by the basis-set superposition error (BSSE) were -14.468 kJ·mol-1 to -5.464 kJ·mol-1. In an effort to comprehend the underlying basis of this interaction, we have also carried out a rigorous decomposition of the interaction energies using the symmetry adapted perturbational theory (SAPT) method. The results indicated that electro-static energies, induction energies, dispersion energies, and exchange-repulsion energies were all important to the total binding energies. The contribution of the induction energy to total attractive energy decreased from 37.8% in BeH2…HF complex to 24.0% in BeH2…HI complex. The dispersion energy dramatically increased from 16.0%in BeH2…HF complex to 33.8% in BeH2…HI complex.