SIGMA-BOND METATHESIS REACTIONS INVOLVING PALLADIUM(II) HYDRIDE AND METHYL COMPLEXES - A THEORETICAL ASSESSMENT

sigma-Bond metathesis reactions of water and methanol with palladium h ydride and methyl complexes to yield hydrogen and methane, respectivel y, have been studied using ab-initio molecular orbital methods at the second-order Moller-Plesset (MP2) perturbation level. The calculations show that such reactions are feasible and that they can in some insta nces be competitive with an oxidative addition/reductive elimination s equence. A key factor is the presence of an additional lone pair not e ngaged in the initial bonding of the metal atom with the reacting wate r or alcohol. Another important controlling factor is the respective c harges of the reacting entities. The importance of the choice and of t he disposition of the ancillary ligands in the coordination sphere is emphasized.