Visible Region Photooxidation on TiO₂ with a Chromophore−Catalyst Molecular Assembly

Abstract

The fabrication of a photoelectrosynthetic cell is described. The cell is based on the adsorption of a chromophore−catalyst molecular assembly onto a transparent ITO-on-glass semiconducting electrode derivatized with high-surface-area TiO2. The adsorbed assembly, [(4,4‘-(CO2H)2bpy)(4,4‘-Me2bpy)RuII(dpp)RuII(tpy)(H2O)]4+ (4,4‘-Me2bpy = 4,4‘-dimethyl-2,2‘-bipyridine; 4,4‘-(CO2H)2bpy = 2,2‘-bipyridine-4,4‘-carboxylic acid; dpp = 2,3-bis(2-pyridyl)pyrazine; tpy = 2,2‘:6‘,2‘ ‘-terpyridine) (see illustration), was irradiated with white light to carry out the oxidative dehydrogenation of 2-propanol (an uphill process by 0.64 eV) by using 2 photoredox equiv by initial oxidation of RuII−OH2 to RuIVO.