Visible region photooxidation on TiO2 with a chromophore-catalyst molecular assembly

The fabrication of a photoelectrosynthetic cell is described. The cell is b ased on the adsorption of a chromophore-catalyst molecular assembly onto a transparent ITO-on-glass semiconducting electrode derivatized with high-sur face-area TiO2. The adsorbed assembly, [(4,4'-(CO2H)(2)bpy)(4,4'-Me(2)bpy)R u-II(dpp)-Ru-II(tpy)(H2O)](4+) (4,4'-Me(2)bpy = 4,4'-dimethyl-2,2'-bipyridi ne; 4, 4'-(CO2H)(2)bpy = 2,2'-bipyridine-4,4'-carboxylic acid; dpp = 2,3-bi s(2-pyridyl)pyrazine; tpy = 2,2':6',2 "-terpyridine) (see illustration), wa s 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 i nitial oxidation of Ru-II-OH2 to RUIV=O.