中文摘要：

采用B3LYP／6—311＋＋G（d，p）和MP2／6—311＋＋G（d，p）理论方法研究了CH3＋Br—YfY=H，CcH，CN，NC）缺电子体系中Br参与的反向卤键（IXB）结构．四个IXB复合物中，MP2／6—311＋＋G（d，p）水平上考虑了基组叠加误差的分子间相互作用能分别为218．87，219．48，159．18和143．05kJ／mol，相对稳定性的递增顺序CH3＋．．BrCN〈CH3＋．．BrNC〈CH3＋．．BrH≈CH3＋．．BrCCH．自然键轨道分析和相关原子化学位移计算表明形成IXB结构时，电子的流向是从Br—Y到CH3＋，采用分了中原予理论方法计算九xBs键鞍点处的电了密度拓扑性质，结果表明CH3＋…Br—Y（Y=H，CCH，CN，NC）缺电子体系中的IxBs结构具有较多的供价成分．

英文摘要：

Inverse halogen bonds interactions involving Br in the electronic deficiency systems of CH3＋...Br-Y （Y=H, CCH, CN, NC） have been investigated by B3LYP/6- 311＋＋G（d, p） and MP2/6-311＋＋G（d, p） methods. The calculated interaction energies with basis set super-position error correction of the four IXBs complexes are 218.87, 219.48, 159.18, and 143.05kJ/mol （MP2/6-311＋＋G（d, p））, respectively. The relative stabilities of the four complexes increased in the order： CH3＋ … BrCN〈CH3＋…- BrNC〈CH3＋… BrH≈CH3＋ …BrCCH. Natural bond orbital theory analysis and the chemical shifts calculation of the related atoms revealed that the charges flow from Br-Y to CH3e. Here, the Br of Br-Y acts as both a halogen bond donor and an electron donor. Therefore, compared with conventional halogen bonds, the IXBs complexes formed between Br-Y and CH3＋. Atoms-in-molecules theory has been used to investigate the topological properties of the critical points of the four IXBs structures which have more covalent content.