复合物C_2H_6·(H_2O)_2中分子间相互作用的理论研究

Theoretica study on the intermolecular interaction of the C_2H_6·(H_2O)_2 complex

在B3LYP/6-311++G**水平上得到C2H6.(H2O)2复合物势能面上四种稳定构型。在相同基组下经MP2电子相关能和基组叠加误差(BSSE)进行单点能量校正,求得单体间相互作用能的大小。结果发现:四种稳定构型都通过CH…O氢键而形成,相应σ(CH)键都出现了较小的收缩,导致伸缩振动发生蓝移,在最稳定的复合物Comp lex2和Comp lex3中,H2O(A)分子的一个H原子与C2H6的两个H原子相对距离较短,并且具有最大的总相互作用能和两个单体AC分子间相互作用能,这说明三个氢原子间存在着较强的相互作用,并对分子的稳定性起着重要作用.

The four optimized geometries of C2H6·（H2O）2 are obtained in B3LYP/6 - 311 ＋ G^＋＋ level. And the intermolecular interaction energy is calculated using the MP2 electron correlation correction and the basis set superposition error correction by the Boys - Bernardi ＂counterpoise＂ protocol. Four stable structures exist on the potential energy surface of the C2H6·（H2O）2 complex formed via a CH…O Hydrogen bond. Under its formation, the corresponding CH bond undergoes a small contraction, resulting in a blue shift of the corresponding v（CH） vibration, in the stable structures Complex 2 and Complex 3, there are relatively short distances between two hydrogen atoms of C2H6 and the hydrogen atom of H2O（A）, the largest total and the largest two - body interaction energies. These suggests the existence of a strong interaction between the three hydrogen atoms, it plays an important role in determining stable molecular conformations.