Water Oxidation Catalyzed by a New Tetracobalt-Substituted Polyoxometalate Complex: [{Co4(µ-OH)(H2O)3}(Si2W19O70)]11

A new polyoxometalate of earth adundant elements [{Co(4)(μ-OH)(H(2)O)(3)}(Si(2)W(19)O(70))](11-) has been synthesized, characterized and shown to be a water oxidation catalyst. The initial catalytic complex is unstable and slowly undergoes hydrolysis. The hydrolysis products have been isolated and characterized, and their catalytic water oxidation activity is assessed