Theoretical study on insertion of silylenoid H2SiLiF into X-H bonds (X=CH3, SiH3, NH2, PH2, OH, SH and F)

The insertion reactions of silylenoid H2SiLiF into X-H bonds (X=CH3, SiH3, NH2, PH2, OH, SH and F), H2SiLiF+XH→H3SiX+LiF, have been theoretically studied using quantum chemistry methods. The structures of reactants, transition states, intermediates, and products were fully optimized at the MP2(full)/6-31G(d) level. The final energies were obtained by the G3(MP2) method. The reaction pathways were identified by intrinsic reaction coordinate (IRC) calculations. The results indicate that when X=CH3, SiH3, PH2, and SH the insertion reactions of silylenoid H2SiLiF into X-H bonds proceed via two reaction pathways, I and II, forming the substituted silanes H3SiX, with dissociation of LiF. When X=NH2, OH, and F the reaction proceed via only pathway I. It is found that all insertion reactions are exothermic. The barriers of pathway II are higher than those of pathway I with the exception of X=SiH3. The reaction mechanism of each pathway was revealed.