Ab Initio Electronic Structure Calculations on Chlorocarbene−Ethylene and Chlorocarbene−Benzene Complexes

Interaction energies for carbene−solvent complex formation have been computed at the MP2/6-311+G**//MP2/6-31G* level, including full counterpoise corrections. Our results indicate that chlorocarbenes do not form stable complexes with ethylene at ambient temperatures and react with tetramethylethylene to form cyclopropanes without an activation energy barrier. Chlorocarbenes and benzene form weakly interacting but thermally stable 1:1 and 1:2 π-type complexes. Two π-type complexes and a hydrogen-bonded ylidic structure were obtained for the 1:1 methylchlorocarbene−anisole system. The formation of carbene−solvent complexes might modulate carbenic reactivity in aromatic solvents.