Photochemical Hydrogen Generation Initiated by Oxidative Quenching of the Excited Ru(bpy)3 (2+) * by a Bio-Inspired [2Fe2S] Complex.

A diiron dithiolate complex 1 containing 1,8-naphthalic anhydride bridge was prepared, which possessed the lowest reduction potential for the synthetic diiron complexes modeled on the active site of [FeFe] hydrogenase reported so far. For the first time, oxidative quenching of the excited Ru(bpy)32+* through electron transfer to a bio-inspired [2Fe2S] complex was corroborated. Hydrogen evolution, driven by visible light, was successfully observed for a three-component system, consisting of Ru(bpy)32+, complex 1, and EDTA as electron donor in aqueous/organic media. These results provide a basis and also opportunity to develop a photo water splitting system employing Fe-based catalysts without sacrificial electron donors.