Density functional theory study on the reactions of X- with CH3SY (X, Y=F, Cl, Br, I)

摘要

Gas-phase anionic reactions X- + CH3SY (X, Y = F, Cl, Br, I) have been investigated at the level of B3LYP/6-311+G (2df,p). Results show that the potential energy surface (PES) of gas-phase reactions X- + CH3SY (X, Y = Cl, Br, I) has a quadruple-well structure, indicating an addition-elimination (A-E) pathway. The fluorine behaves differently in many respects from the other halogens and the reactions F- + CH3SY (Y = F, Cl, Br, I) correspond to deprotonation instead of substitution. The gas-phase reactions X- + CH,SF (X = Cl, Br, I), however, follow an A-E pathway other than the last two out going steps (COM2 and PR) that proceeds via a deprotonation. The polarizable continuum model (PCM) has been used to evaluate the solvent effects on the energetics of the reactions X- + CH3SY (X, Y = Cl, Br, I). The PES is predicted to be unimodal in the solvents of high polarity. (C) 2006 Wiley Periodicals, Inc.