Reactivity of cyanogen with monocarbonylnickel(0) complexes. Examples of combined oxidative substitution and internal ligand substitution

Abstract

The complex [Ni(CO)(dppb)₂](dppb = Ph₂P[CH₂]₄PPh₂) undergoes a two-stage reaction with C₂N₂ in CH₂Cl₂, at room temperature. The first stage gives almost equivalent quantities of [{Ni(CN)₂(dppb)}₂] and [Ni(CO)₂(dppb)], whereas quantitative conversion of [Ni(CO)₂(dppb)] into [{Ni(CN)₂(dppb)}₂] and CO is obtained in the second stage. The complexes [Ni(CO)(dppb){P(OR)₃}](R = Et or Ph) react in a similar way under particular conditions. A kinetic investigation has been carried out on the first system and a reaction mechanism is proposed for its first stage.