Abstract: 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.

Key words: (CH3)2S, HOCl, Halogen bond complex, NBO, AIM