Coordination chemistry in electrocatalysis

Superior electrocatalysts for the reduction of O_2 by four-electrons in one step have been prepared by coordinating ammine complexes of Ru(II) to the pyridine ligand sites in cobalt tetrakis(4-pyridyl) porphyrin. At least three coordinated Ru(II) centers appear to be required to obtain the four-electron reduction. When fac-Ru(NH_3)_3(OH_2)_3^(2+) was used to ruthenate the porphyrin, a network structure was obtained in which both terminal and bridging ruthenium centers were present