Substitution reactions of dinuclear alkenyl-bridged iron-cobalt complexes with phosphines. Crystal structures of [(CO) 3 Fe-Co(CO) 2(PMe 2Ph)] (μ-C(CO 2Me)C(CO 2Me)H) and [(CO) 2(PMe 2Ph)FeCo(CO) 2(PMe 2Ph)]-(μ-C(CO) 2Me)C(CO 2Me)H)

Abstract

The bridging alkenyl iron-cobalt complexes [(CO) 4FeCo(CO) 3(μ-CR 1CR 2H) (R 1CO 2Me or CO 2Et and R 2  H; R 1  H and R 2  H or Ph react with one equivalent of PMe 2Ph or PPh 3 to give monosubstituted complexes with the phosphine ligand coordinated to the iron atom. When R 1  CO 2Me or CO 2Et and R 2  H, addition of two equivalents of PPh 3 produces complexes with two PPh 3 ligands coordinated to each metal. The complex [(CO) 3FeCo(CO) 3](μ-C(CO 2Me)(CO 2Me)H) also reacts with one equivalent of PMe 2Ph, PMePh 2, PPh 3 or PPh 2H to give monosubstituted complexes with the phosphine ligand bonded to the cobalt atom. The reaction of the complex [(CO) 3FeCo(CO) 3](μ-C(CO 2Me)(CO 2Me)H) with PPh 3 gives a complex with the phosphine coordinated to the iron atom, but addition of two phosphines gives complexes with one phosphine ligand bonded to each metal. The structures of the products [(CO) 3FeCo(CO) 2(PMe 2Ph)](μ-C(CO 2Me)C(CO 2Me)H) and [(CO) 2(PMe 2-Ph)FeCo(CO) 2(PMe 2Ph)]μ-C(CO 2Me)(CO 2Me)H) obtained from the reaction of the [(CO) 3FeCo-(CO) 3](μ-C(CO 2Me)C(CO 2 Me)H) complex with one and two equivalents of PMe 2Ph, respectively, have been determined by X-ray crystallography.