Reactions of dioxygen with benzylnickel complexes

Abstract

The benzyl complexes Ni(X)(CH2C6H5)(PCy3) (X = Cl, CN; Cy = cyclohexyl) react with molecular oxygen to give benzaldehyde and benzyl alcohol as main oxidation products. The ratio of the two products is strongly dependent on the nature of X and is also influenced by the solvent and the temperature. Isotopic labelling and mass spectra show that the hydrogen atoms necessary for the formation of the benzyl alcohol are supplied by the phosphine ligands. Isolation and characterization of the chloride complex by conventional spectroscopic techniques (IR, 1H 31P NMR, visible spectra) provide evidence in favour of a η3-τ-benzyl structure for the compound. © 1986.