Molybdenum—sulfur chelates as catalysts in the reductive cleavage of azobenzene by electron donors in protic media

Abstract

A variety of molybdenum complexes ranging in their formal oxidation states from II to VI have been examined as catalysts in the electron transfer reduction (by NaBH 4 or Na 2S 2O 4) and reductive cleavage of azobenzene. Among many sulfur-chelated binuclear molybdenum complexes, the sulfur-double bridged ones, Mo 2O 2S 2(LL) 2 (LL = S 2CNR 2, S 2COR, R = Et, i-Pr, neo-Pent), were found to be effective at room temperature for aniline formation. The catalysis and co-catalysis of tetra-iron sulfur clusters [Fe 4S 4(S-R) 4] 2− were also examined for the reductive cleavage of azobenzene.