College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022, China.
J Phys Chem A. 2011 Aug 25;115(33):9294-9. doi: 10.1021/jp204744m. Epub 2011 Aug 1.
The Cambridge Structure Database search shows that there are over seventy crystal structures containing halogen bonds in which hypervalent halogens, not monovalent halogens as usual, behave as acceptors of electron density. The nature of the halogen bond involving hypervalent halogen has been investigated by using several theoretical methods with different basis sets. The HF calculations for the complexes studied cover most of their binding energies, which indicates the electrostatic nature of the halogen bond involving hypervalent halogen. The MP2 methods with medium basis sets fail to predict the relative strength of the halogen bond involving hypervalent halogen and the corresponding halogen bond involving monovalent halogen. Accurate computational results show that the halogen bond involving hypervalent halogen may be weaker than the corresponding halogen bond involving monovalent halogen even in the case that the hypervalent halogen is more positively charged than the monovalent halogen, the reasons of which were discussed in some detail. In comparison with the halogen bond involving monovalent halogen, the bonding characteristic and electron-density transfer of the halogen bond involving hypervalent halogen were also analyzed with the "atoms in molecules" theory and the natural bond orbital theory.
剑桥结构数据库搜索表明，有超过 70 个晶体结构包含卤键，其中高价卤素而不是通常的单价卤素作为电子密度的受体。已经使用几种不同基组的理论方法研究了涉及高价卤素的卤键的性质。对所研究的配合物进行 HF 计算，涵盖了它们大部分的结合能，这表明了涉及高价卤素的卤键的静电性质。中等基组的 MP2 方法无法预测涉及高价卤素的卤键与相应的涉及单价卤素的卤键的相对强度。准确的计算结果表明，即使高价卤素比单价卤素带更多的正电荷，涉及高价卤素的卤键也可能比相应的涉及单价卤素的卤键弱，详细讨论了其中的原因。与涉及单价卤素的卤键相比，还使用“分子中的原子”理论和自然键轨道理论分析了涉及高价卤素的卤键的成键特征和电子密度转移。
