(CH3)2S与HOCl分子间的卤键和氢键相互作用

在DFT-B3LYP/6-311++G**水平上分别求得(CH3)2S…ClOH卤键复合物和(CH3)2S…HOCl氢键复合物势能面上的稳定构型. 频率分析表明, 与单体HOCl相比, 在两种复合物中, 10Cl—11O和12H—11O键伸缩振动频率发生显著的红移. 经MP2/6-311++G**水平计算的含基组重叠误差(BSSE)校正的气相中相互作用能分别为-11.69和-24.16 kJ·mol-1. 自然键轨道理论(NBO)分析表明, 在(CH3)2S…ClOH卤键复合物中, 引起10Cl—11O键变长的因素包括两种电荷转移: (i) 孤对电子LP(1S)1→σ*(10Cl—11O); (ii) 孤对电子LP(1S)2→σ*(10Cl—11O), 其中孤对电子LP(1S)2→σ*(10Cl—11O)转移占主要作用, 总的结果是使σ*(10Cl—11O)的自然布居数增加0.14035e, 同时11O原子的再杂化使其与10Cl成键时s成分增加, 即具有与电荷转移作用同样的“拉长效应”; 在(CH3)2S…HOCl氢键复合物中也存在类似的电荷转移, 但是11O原子的再杂化不同于前者. 自然键共振理论(NRT)进行键序分析表明, 在卤键复合物和氢键复合物中, 10Cl—11O和12H—11O键的键序都减小. 通过分子中原子理论(AIM)分析了复合物中卤键和氢键的电子密度拓扑性质.

Halogen Bond and Hydrogen Bond Interactions between (CH3)2S and HOCl

The optimized stable (CH3)2S…ClOH halogen bond and (CH3)2S…HOCl hydrogen bond complexes were found on the potential energy surface by means of DFT-B3LYP/6-311++G**. The obvious red shifts of the 10Cl—11O and 12H—11O stretching vibrational frequencies in the two complexes were obtained via frequency analysis. The halogen bond interaction energy of (CH3)2S…ClOH was -11.69 kJ·mol-1, and the hydrogen bond interaction energy of (CH3)2S…HOCl was -24.16 kJ·mol-1, which were calculated with basis set superposition error (BSSE) correction via counterpoise procedure (CP) method at MP2/6-311G** level. Natural bond orbital (NBO) theory analysis showed that two kinds of charge transfers existed in (CH3)2S…ClOH halogen bond system: (i) lone pair LP(1S)1→σ*(10Cl—11O); (ii) lone pair LP(1S)2→σ*(10Cl—11O), and the natural population of the σ*(10Cl—11O) increased by 0.14035e. Analogous charge transfers existed in (CH3)2S…HOCl hydrogen bond complex. Bond order analysis with natural resonance theory (NRT) showed that bond order of 10Cl—11O in (CH3)2S…ClOH halogen bond complex and bond order of 12H—11Oin (CH3)2S…HOCl hydrogen bond complex both decreased. The topological properties of the halogen bond and hydrogen bond structures were also investigated by the atoms-in-molecules (AIM) theory.