Theoretical study on the addition reactions of silylenoids H2SiLiX (XÂ =Â F, Cl) to formaldehyde

The addition reactions of silylenoids H2SiLiX (X = F, Cl) to formaldehyde were studied using ab initio and DFT methods. The three-membered ring structures and the p-complex structures of H2SiLiX were adopted. The structures of reactants, transition states and products were fully optimized at the B3LYP/6-311+G(d,p) and MP2 (full)/6-31G(d) levels. G3(MP2) theory was used for calculations of molecular energies. The reaction paths were investigated and confirmed by intrinsic reaction coordinate calculations. The difference between the asymmetric addition reactions of H2SiLiX to formaldehyde and the symmetric addition reactions of H2SiLiX to ethylene and acetylene was also discussed. At the B3LYP/6-31G(d) level, calculations about solvent effects on the addition reactions of H2SiLiX to formaldehyde show that the additions are easier to occur in the polar solvent, and the higher the solvent polarity is, the lower the barriers of the addition reactions are.