Activation of hydrogen by rhodium complexes containing sulphide ligands. Part II. The trichlorotris(diethyl sulphide)rhodium(III)-catalysed hydrogenation of maleic acid

Abstract

RhCl₃(Et₂S)₃ has been found to catalyse the homogeneous hydrogenation of olefinic substrates in NN′-dimethylacetamide solution at ca. 70° and 1 atm. pressure. The kinetics have been interpreted in terms of an initial reduction to a rhodium(I) species, which with co-ordinated olefin then activates molecular hydrogen. The basic solvent plays an important role in initially promoting dissociation of a sulphide ligand from the rhodium(III) complex, and probably in enhancing an overall heterolytic splitting of the H₂ molecule in production of a rhodium(III) hydride intermediate.