New Catalysts for the Electrochemical Reduction of Proton

Iron acetylide Ср(СО)(Ph3P)Fe–C≡CPh (Fe1), rhenium vinylidene Cp*(CO)2Re=С=С(H)Ph (Re1), and manganese isonitrile complexes Cp(CO)2Mn=С=NR (Mn3, R = Me; Mn4 R = tBu) were tested for activity in the electrochemical reduction of proton (ERP). Complexes Fe1 and Re1 were found to be catalytically active in the ERP. Their protonated forms [Ср(СО)(Ph3P)Fe=C=C(H)Ph]BF4 (Fe1H+) and [Cp*(CO)2Re≡С‒СH2Ph]BF4 (Re1H+) were reduced to corresponding 19e radicals (Fe1H▪) and (Re1H▪) followed by homolysis of Cβ–H bonds to regenerate starting complexes Fe1 and Re1.