Ab-inito Calculations in Reductive Bond-breaking Reaction of C-X Bond in CH3X and CH2X2 with X = F and CI

MP4/6-31+G* level calculations are performed to study the reductive bond-breaking reaction of the C-X bond in halomethanes, CH₃X and CH₂X₂ where X is a fluorine atom or chlorine atom. This type of reaction involves a radical anion, after attaching an extra electron to the halomethane molecule, in which a C-X bond-breaking takes place. Products are a radical and a halogen anion. The equilibrium geometry and bond dissociation energy of the C-X bond thus found are in good agreement with previous theoretical and experimental results. The anomeric effect, electrostatic effect, and radical re-stabilization effect, are investigated to find their influences on bond length and bond dissociation energy in CH₃X and CH₂X₂. Potential energy curves are calculated for the reductive bond-cleavage process, and trends in activation energy for various cases are discussed.