Abstract: The optimized stable (CH3)2S…HOO and (CH3)2O…HOO hydrogen bond complexes were found on the potential energy surface at B3LYP/6-311++G** level. The obvious red shifts of the H10-O11 stretch vibration in the two hydrogen bond complexes were obtained by frequency analysis, and the red shift values were 424.21 and 374.22 cm-1, respectively. The hydrogen bond of S1(O1)…H10 interaction energy were -24.68 and 31.01 kJ·mol-1, which was calculated with basis set superposition error (BSSE) and zero point vibrational energy (ZPVE) correction at MP2 level. Natural bond orbit (NBO) theory analysis showed that two kinds of charge transfer exist in (CH3)2S…HOO hydrogen bond complex: (1) LP(S1)1→σ*(H10-O11); (2) LP(S1)2→σ*(H10-O11), and the natural population of the σ*(H10-O11) increased by 37.27 me. Analogous charge transfers existed in (CH3)2O…HOO hydrogen bond complex. Bond order analysis with nature resonance theory (NRT) showed that H10-O11 bond order decreased both in (CH3)2S…HOO and (CH3)2O…HOO hydrogen bond complexes. This agreed with the charge transfer discussion and frequency analysis. The topological properties of the hydrogen bond structures were also investigated by the atom-in-molecules (AIM) theory, and the results showed that there exist bond critical points between S1(O1) and H10.

Key words: (CH3)2S, HOO, Hydrogen bond complexes, NBO theory, AIM theory