Résumé
The ability of [(
η
5-C
5Me
5)M
III(L)Cl]
+ complexes (M = Rh and Ir. L = 2,2′-bipyridine and 1, 10-phenanthroline) to act as electrocatalysts for the hydrogenation of unsaturated organic substrates has been examined in homogeneous acetonitrile solution, using formic acid as a proton source, as well as in aqueous electrolytes with electrodes modified by oxidative electropolymerization of pyrrole-substituted Rh(III) and Ir(III) complexes. The hydrogenation process involves the formation of an electrogenerated hydrido complex, followed by the insertion of the substrate in the metal-hydride bond. It appears that rhodium complexes are better catalysts than the iridium ones, and that their immobilization onto an electrode surface decreases their catalytic activity.