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采用HF方法和6-31G(d,p)基组,对C_4H_4N_2…2ClF复合物中的卤键作用进行研究,并讨论随着卤离子的加入,形成X~-…C_4H_4N_2…2ClF(X~-=F~-,Cl~-,Br~-)复合物之后,卤离子对该类卤键的加强作用。通过分析分子表面静电势,搭建复合物构型,优化得到了复合物的稳定构型并进行了频率分析。用电子密度拓扑分析方法研究复合物中卤键的性质,探讨了该类卤键的作用本质。研究结果表明:(1)C_4H_4N_2可以通过氮原子外的负静电势区域与ClF分子中Cl原子外的正静电势区域结合形成2个N…Cl卤键,卤离子F~-、Cl~-和Br~-与C_4H_4N_2中的2个H原子可以形成氢键,这个氢键对N…Cl卤键有明显的加强作用,且按照Br~-、Cl~-和F~-的顺序,加强作用越来越明显。(2)电子密度拓扑分析表明,复合物C_4H_4N_2…2ClF、Br~-…C_4H_4N_2…2ClF、Cl~-…C_4H_4N_2…2ClF、F…C_4H_4N_2…2ClF的N…Cl卤键强度依次增加;N…Cl卤键属于闭壳层相互作用。
The halogen bond in C_4H_4N_2 ... 2ClF complex was studied by HF method and 6-31G (d, p) basis set. The formation of X ~ - ... C_4H_4N_2 ... 2ClF (X ~ = F ~ -, Cl ~ -, Br ~ -) complex, halogen ions on the halogen bond to strengthen the role. By analyzing the electrostatic potential on the surface of the molecule, the complex configuration was established, the stable configuration of the complex was optimized and the frequency was analyzed. The electron-density topological analysis method was used to study the properties of halogen bond in the complex, and the nature of the halogen bond was discussed. The results show that: (1) C_4H_4N_2 can form two N ... Cl halogen bonds, halogen ions F ~ -, Cl ~ -, and Cl ~ - by combining the negative electrostatic potential region outside the nitrogen atom with the positive electrostatic potential region outside the Cl atom in the ClF molecule Br ~ - and C_4H_4N_2 H atoms can form two hydrogen bonds, the hydrogen bond on the N ... Cl halogen bond has a significant role in strengthening, and in accordance with Br ~ -, Cl ~ - and F ~ - the order of strengthening the role of The more obvious. (2) The topological analysis of electron density shows that the intensity of N-Cl halogen bonds of C_4H_4N_2 ... 2ClF, Br ~ - ... C_4H_4N_2 ... 2ClF, Cl ~ - ... C_4H_4N_2 ... 2ClF, F ... C_4H_4N_2 ... 2ClF increase in turn; The bond belongs to the closed shell interaction.