Oxidative Addition of Haloalkanes to Metal Centers: A Mechanistic Investigation

Photolysis
of CpRe­(CO)3 in the presence of dichloromethane
results in the initial formation of the CpRe­(CO)2(ClCH2Cl) complex followed by insertion of the metal into the C–Cl
bond. The activation enthalpy is determined to be 20.4 kcal/mol, and
with the assistance of DFT calculations, a radical mechanism is proposed
for the oxidative addition reaction. Photolysis of Ni­(CO)2(PPh3)2 with dihalomethanes also results in
oxidative addition, but the intermediacy of a halogen-bound adduct
has not been established.