The preparation and characterization
of new Ru(II) polypyridyl-based chromophore–catalyst assemblies,
[(4,4′-PO<sub>3</sub>H<sub>2</sub>-bpy)<sub>2</sub>Ru(4-Mebpy-4′-epic)Ru(bda)(pic)]<sup>2+</sup> (<b>1</b>, bpy = 2,2′-bipyridine; 4-Mebpy-4′-epic
= 4-(4-methylbipyridin-4′-yl-ethyl)-pyridine; bda = 2,2′-bipyridine-6,6′-dicarboxylate;
pic = 4-picoline), and [(bpy)<sub>2</sub>Ru(4-Mebpy-4′-epic)Ru(bda)(pic)]<sup>2+</sup> (<b>1</b>′) are described, as is the application
of <b>1</b> in a dye-sensitized photoelectrosynthesis cell (DSPEC)
for solar water splitting. On SnO<sub>2</sub>/TiO<sub>2</sub> core–shell
electrodes in a DSPEC configuration with a Pt cathode, the chromophore–catalyst
assembly undergoes light-driven water oxidation at pH 5.7 in a 0.1
M acetate buffer, 0.5 M in NaClO<sub>4</sub>. With illumination by
a 100 mW cm<sup>–2</sup> white light source, photocurrents
of ∼0.85 mA cm<sup>–2</sup> were observed after 30 s
under a 0.1 V vs Ag/AgCl applied bias with a faradaic efficiency for
O<sub>2</sub> production of 74% measured over a 5 min illumination
period
