Study on a series of CT complexes of amine(or NH3)-CHCl3 with DFT method

The theoretical study on a series of complexes forming from amine [CH3NH2, (CH3)(2)NH and (CH3)(3)N]or ammonia (NH3), and CHCL3 via weak chemical inte raction was carried out. The complexes were considered as supermolecules an d calculated with DFT method at B3LYP/6 - 311G(d,p) level, and the basis se t 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 chan ge 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)(2)NH - CHCl3(III) > (CH3)(3)N - CHC4(N). There is an obvious charge - transfer in the process of forming the complexes. T he stability of the series of complexes keeps a good linear relation to the CT amount, the energy gap Delta epsilon (L-H) between LUMO and HOMO, and t he distance of extended H - bond. In addition, it is also related to the at omic net charges of the donor center and acceptor center, etc. The analysis of the stability regularity of the complexes must be considered synthetica lly both of the covalent interaction and static charge interaction between the molecules. The calculation results can be better used to explain some e xperimental phenomena and regularities.