过渡金属M(M=Cu,Ag,Au)对X…Cl(X=F,Cl,Br)卤键相互作用强度的影响

摘要

采用量子化学方法,通过MCH2X…CIF (M=Cu,Ag,Au;X=F,Cl,Br)和CH3X…CIF两类复合物的对比,探讨了过渡金属对卤键相互作用强度的影响.CH3X…CIF复合物只有卤键相互作用,而优化MCH2X…CIF复合物除了得到一种只含有卤键相互作用的构型外,还得到一种含有过渡金属和CI原子相互作用的稳定构型.含有过渡金属的复合物稳定性明显增加,Ag取代的复合物稳定性增加最为明显,Cu次之,Au最不明显.X原子最负分予表面静电势(MEP)减小是复合物稳定性增加的根本原因.利用自然键轨道(NBO)及分子中原子(AIM)分析进一步对体系的分子间相互作用进行了探讨.二阶稳定化能与键鞍点处拓扑性质的计算结果与相互作用能符合得很好.%Intermolecular complexes of MCHzX-CIF (M=Cu, Ag, Au; X = F, Cl, Br) and CHsX-CIF were investigated using by quantum chemistry method. Only one stable structure containing a halogen bond was obtained for the CH3X-CIF complexes. For the MCH3X...CIF complexes, as well as the halogen-bonded complex, another optimized structure containing both a halogen bond and M...CI interaction was determined. The stability of the MCH2X...CIF complexes was greater than that of the CH3X...CIF complexes. Substitution with M improves the stability of the resulting complex with the order Ag>Cu>Au. The most negative molecular electrostatic potential of X in MCH2X and CHsX was calculated, and the decrease of this value is the main reason for the enhanced stability of these complexes. The characteristics of these complexes were also studied by natural bond orbital and atoms in molecules methods. The second-order perturbation energy and topological properties of the saddle points were calculated and the results were consistent with the interaction energy.