Intermolecular electron transfer from photogenerated Ru(bpy)3+ to [2Fe2S] model complexes of the iron-only hydrogenase active site.

Visible light-driven intermolecular electron transfer was observed from a reduced species Ru(bpy)3+, photogenerated via a reductive quenching of the ruthenium photosensitizer by a diethyldithiocarbamate anion, to bioinspired [2Fe2S] model complexes of the iron-only hydrogenase active site. The results indicate that Ru(bpy)32+ can act as a photoactive functional model of the [4Fe4S] cluster, playing the role of an electron-transfer relay. The photogenerated FeIFe0 species, which is proposed to be a crucial intermediate for proton reduction catalyzed electrochemically by the [2Fe2S] complexes, gives promise in the light-driven dihydrogen evolution using diiron complexes as surrogates of noble platinum catalysts.