The reaction of anhydrous FeCl3 and 1,4,7,10-tetraazacyclododecane (L) affords an iron(III) complex, [LFeCl2]Cl (1), a new molecular electrocatalyst, which has been determined by X-ray crystallography. Electrochemical studies indicate that the catalyst is the first water-soluble molecular species, that is among the most rapid homogeneous water oxidation catalysts, with a turnover frequency of similar to 65 s(-1). Sustained water oxidation catalysis occurs at ITO electrode to give O-2 over a 36 h electrolysis period with 91.5% Faradaic yield and no observable decomposition of the catalyst. (C) 2014 Elsevier B.V. All rights reserved.