Cobalt analogs of Ru-based water oxidation catalysts: overcoming thermodynamic instability and kinetic lability to achieve electrocatalytic O2 evolutionElectronic supplementary information (ESI) available: Experimental procedures, compound characterization data. CCDC 885442 and 885443. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c2sc20755a

Several binuclear cobalt( iii ) complexes that mimic Ru-based water oxidation catalysts have been prepared. The initial complexes exhibited thermodynamic instability and kinetic lability that complicated efforts to use these cobalt complexes as electrocatalysts for water oxidation. Binuclear cobalt( iii ) complexes supported by a bridging bispyridylpyrazolate (bpp) ligand overcome these limitations. Two bpp-ligated dicobalt( iii )-peroxo complexes were prepared and structurally characterized, and electrochemical investigation of these complexes supports their ability to serve as molecular electrocatalysts for water oxidation under acidic conditions (pH 2.1). The first binuclear Co( iii ) complex capable of mediating electrocatalytic water oxidation has been prepared and characterized via crystallography, spectroscopy and voltammetry.