Abstract:We synthesized 1,8-bis(2,2 :6 ,2"-terpyrid-4 -yl)anthraquinone (btpyaq) as a new dimerizing ligand and determined its single crystal structure by X-ray analysis. The dinuclear Ruthenium complex [Ru 2 (µ-Cl)(bpy) 2 (btpyaq)](BF 4 ) 3 ([3](BF 4 ) 3 , bpy = 2,2 -bipyridine) was used as a catalyst for water oxidation to oxygen with (NH 4 ) 2 [Ce(NO 3 ) 6 ] as the oxidant (turnover numbers = 248). The initial reaction rate of oxygen evolution was directly proportional to the concentration of the catalyst and independent of the oxidant concentration. The cyclic voltammogram of [3](BF 4 ) 3 in water at pH 1.3 showed an irreversible catalytic current above +1.6 V (vs. SCE), with two quasi-reversible waves and one irreversible wave at E 1/2 = +0.62, +0.82 V, and E pa = +1.13 V, respectively. UV-vis and Raman spectra of