Electrochemically induced transformations of bi- and trinuclear heterometallic vinylidene complexes containing Re, Pd and Fe

Redox-induced transformations of bi-Cp(CO)(2)RePd(mu-C=CHPh)(PPh3)(2) (2), Cp(CO)(2)RePd(mu-C=CHPh)(P-P) [P-P = n(2)-Ph2P(CH2)(2)PPh2 (dppe) (3), n(2)-Ph2P(CH2)(3)PPh2 (dppp) (4)], Cp(CO)(2)ReFe(mu-C=CHPh)(CO)(4) (5) and trinuclear cp(CO)(2)ReFe2(mu(3)-C=CHPh)(CO)(6) (6), CpReFePd(mu(3)-C=CHPh)(CO)(5)(P-P) [P-P = dppe (7), dppp (8)] heterometallic vinylidene complexes derived from Cp(CO)(2)Re=C=CHPh (1) were investigated by electrochemical methods. The oxidation processes of clusters 7 and 8 were studied by EPR spectroscopy. The electrochemical properties of clusters 7 and 8 were shown to depend on the nature of the chelate diphosphine ligand at the palladium center in contrast to complexes 3 and 4. The oxidation of complexes 2-4 was found to result in the Re-Pd, Pd-C bond cleavage and formation of rhenium complex 1 and Pd-containing fragments. The oxidation of 7 and 8 resulted in the formation of the radical cations 7(+.) and 8(+.), which sequentially transformed into a number of intermediate products: Cp(CO)(2)RePd(mu-C=CHPh)(P-P), [Fe(CO)(3)](+.), [CpReFe2(mu(3)-C=CHPh)(CO)(6])(+.) and others. The final products of their oxidation in both cases were triangular clusters (CO)(8)Fe2Pd(P-P) [P-P = dppe (9), dppp (10)] and rhenium complex 1. The molecular structure of cluster 7 was established by X-ray diffraction analysis. (C) 2017 Elsevier B.V. All rights reserved.