REACTION OF PI-ALLYL COMPOUNDS OF NICKEL PALLADIUM AND PLATINUM WITH IRON NONACARBONYL

The reaction of iron carbonyls with the π-allyl compounds of nickel, palladium and platinum has been studied. Bis(π-allylpalladium chloride), for example, has been shown to react first with fission of the μ-halide bridges in the dimeric molecule of (π-C3H5PdCl)2. In the intermediate formed there is an intermolecular π-π-migration of the allyl ligand from palladium to the iron atom. The NMR study of the reaction mixture indicates that this migration is preceded by π-σ-perturbation in the π-allyl ligand. Thus, the migration of the C3H5-ligand takes place in three stages: coordination with the Fe(CO)4-fragment, transformation of the ligand from the π- into the σ-bonded form, and finally the ligand migration itself, i.e., the main stages responsible for the homogeneous catalysis by the transition-metal complexes. © 1969.