Organometallic complexes of transition metals, free of carbon monoxid are produced electrochemically by electrolysis in a cell having two metal electrodes and electrolyte solution comprising an organic solvent, a suitable complexing agent and, optionally, a conducting salt. The transition metal compounds involved comprise those of Groups IVb to VIIb and VIII and they may be used in metallic form as the anode. The cathode is advantageously a metal toward which the electrolyte is inert, e.g. aluminum. The complexing agent preferably comprises a compound of a transition metal of Group IVb, VIb or VIII, e.g. an acetylacetonate, organic acid salt or alkanolate of titanium, chromium, iron, cobalt or nickel. Quaternary ammonium or alkali metal salts may be used as conductors. The products are suited for catalysis of hydrogenation, oligomerization and isomerization.