Roles of H₂O to hydrogen bonds, structure and strength of complexes of CH₃CHS and H₂O

Abstract

Six stable geometrical structures of the interaction between CH₃CHS and H₂O were observed on potential energy surface at the MP2/ aug-cc-pVDZ level of theory. Interaction energies corrected by both ZPE and BSSE for all the complexes at the MP2/aug-cc-pVTZ//MP2/aug-cc-pVDZ high level of theory range from -12.0 to -61.4 k.J.mol⁻¹ . When adding water molecule to CH₃CHS, stabilily of interacting system and cooperative capacity of complexes are increased. In general, the strength of complexes is contributed by O-H...O/S and C-H...O hydrogen bonds, and their stability decreases in the order of O-H...O > O-H...S > C-H...O. Interestingly, a larger contraction and a stronger increase of stretching frequency of Csp₂> H bond as compared to Csp₃-H bond are observed following complexation although the Csp₂-H...O H-bonds are stronger than the Csp₃ H...O counterparts. This detective result is mainly dctermined by a decrease in the electron density of the σ*(C-H) orbital.