The contrasting roles of the various chalcogens in the synthesis of mixed metal complexes (CO)<SUB>6</SUB>Fe<SUB>2</SUB>(μ<SUB>3</SUB>-E)<SUB>2</SUB>M(PPh<SUB>3</SUB>)<SUB>2</SUB> (E = Te, Se, S; M = Ni, Pd, Pt))

Reactions of Fe3E2(CO)9 (E = S, Se) with M(PPh3)4 (M = Ni, Pd, Pt), at room temperature, show a marked contrast with the analogous reaction of Fe3Te2(CO)9. Different mechanisms are suggested for the formation of the mixed-metal complexes, Fe2E2(CO)6M(PPh3)2 (E = S, Se, Te; M = Pd, Pt, and E = Te; M = Ni), depending on the chalcogen atom involved. The size of the chalcogen and that of the heterometal atom play crucial roles in the outcome of the reaction