Wang Yong, Li Haoran, Han Shijun
Department of Chemistry, Zhejiang University, Hangzhou 310027, People's Republic of China.
J Chem Phys. 2005 Nov 1;123(17):174501. doi: 10.1063/1.1979478.
The structures and conformational properties of 1-alkyl-3-methylimidazolium halide ionic liquids have been studied with a Becke's 3 Parameter functional method. The interaction mechanisms between the cation and the anion in 1-ethyl-3-methylimidazolium (Emim+) halide and 1-butyl-3-methylimidazolium (Bmim+) halide ionic liquids were investigated using 6-31G*, 6-31++G**, and 6-311++G** basis sets. Forty structures of different ion pairs were optimized and geometrical parameters of them have been discussed in details. Halide ions (Cl- or Br-) have been gradually placed in different regions around imidazolium cation and the interaction energies between the anion and the cation have been calculated. Theoretical results indicate that there are four activity regions in the vicinity of the imidazolium cations, in these regions the imidazolium cations and the halide anions formed stable ion pairs. Imidazolium cations can form hydrogen bond interactions with one, two or three but no more than three nearest halide anions. The halide ions are situated in hydrogen bond positions rather than at random.
采用Becke三参数泛函方法研究了1-烷基-3-甲基咪唑鎓卤化物离子液体的结构和构象性质。使用6-31G*、6-31++G和6-311++G基组研究了1-乙基-3-甲基咪唑鎓（Emim+）卤化物和1-丁基-3-甲基咪唑鎓（Bmim+）卤化物离子液体中阳离子与阴离子之间的相互作用机制。优化了40种不同离子对的结构，并详细讨论了它们的几何参数。卤离子（Cl-或Br-）被逐渐放置在咪唑鎓阳离子周围的不同区域，并计算了阴离子与阳离子之间的相互作用能。理论结果表明，在咪唑鎓阳离子附近存在四个活性区域，在这些区域中咪唑鎓阳离子与卤离子形成稳定的离子对。咪唑鎓阳离子可以与一个、两个或三个但不超过三个最近的卤离子形成氢键相互作用。卤离子位于氢键位置而非随机分布。
