Water oxidation catalyzed by a dinuclear cobalt-polypyridine complex.

The dinuclear Co complex [(TPA)Co(μ-OH)(μ-O2 )Co(TPA)](ClO4 )3 (1, TPA=tris(2-pyridylmethyl)amine) catalyzes the oxidation of water. In the presence of [Ru(bpy)3 ](2+) and S2 O8 (2-) , photoinduced oxygen evolution can be observed with a turnover frequency (TOF) of 1.4±0.1 mol(O2 ) mol(1)(-1)  s(-1) and a maximal turnover number (TON) of 58±5 mol(O2 ) mol(1)(-1) . The complex is shown to act as a molecular and homogeneous catalyst and a mechanism is proposed based on the combination of EPR data and light-driven O2 evolution kinetics.