胺(或氨)一CHCI3系CT复合物密度泛函法研究

报道对氨(NH3,母体)、甲胺(CH3NH2)、二甲胺[(CH3)2NH]、三甲胺[(CH3)3N]与三氯甲烷(CHCL3)形成的系列复合物的理论研究结果．把复合物看作一个超分子,在B3LYP/6-311G(d,p)的水平上进行密度泛函法计算,并运用完全均衡校正法进行基组超位误差校正(BSSE).探讨该系列复合物的电子结构与相关性质,如稳定性、电荷转移及主要几何参数的变化规律等.结果表明,形成复合物的稳定性次序为NH3-CHCl3(Ⅰ)>CH3NH2-CHCL3(Ⅱ)>(CH3)2NH-CHCl3(Ⅲ)>(CH3)3N-CHCl3(Ⅳ).形成复合物的过程包含着电荷转移.该系列复合物的稳定性与电荷转移量、前线轨道能量差ΔεL-H及广义H键距离有良好的线性关系,与结合点的电荷布居也有密切的关系.复合物的稳定性是分子间共价作用和静电作用两方面因素综合的结果.计算结果能较好地解释有关的实验现象和规律.

Study on a Series of CT Complexes of Amine(or NHs) -CHCls with DFT Method

The theoretical study on a series of complexes forming from amine [ CH3NH2, (CH3)2NH and (CH3)3N]or ammonia (NH3), and CHCl3 via weak chemical interaction was carried out. The complexes were considered as supermolecules and calculated with DFr method at B3LYP/6 - 311G(d,p) level, and the basis set superposition error (BSSE) was corrected by the counterpoise method. The electronic structure and its related properties, e. g., regularities of the stability, the charge transfer between the donor and acceptor, and the change of geometric parameters of the complexes were investigated. The results show that the stability of the complexes is in the order: NH3-CHCl3 (Ⅰ)>CH3NH2-CHCl3 (Ⅱ) > (CH3)2NH - CHCl3 (Ⅲ)> (CH3)3N-CHCl3(Ⅳ). There is an obvious charge-transfer in the process of forming the complexes. The stability of the series of complexes keeps a good linear relation to the CT amount, the energy gap ΔεL- H between LUMO and HOMO, and the distance of extended H-bond. In addition, it is also related to the atomic net charges of the donor center and acceptor center, etc. The analysis of the stability regularity of the complexes must be considered synthetically both of the covalent interaction and static charge interaction between the molecules. The calculation results can be better used to explain some experimental phenomena and regularities.