Binuclear Phthalocyanines as Model Electrocatalysts for the Reduction of Oxygen.

Abstract : Binuclear cobalt phthalocyanines linked by bridges containing 1, 2, 4, or 5 atoms are shown to reduce oxygen catalytically, more efficiently than mononuclear cobalt phthalocyanines. The kinetic efficiency for oxygen reduction is related to the degree of electronic coupling between the two halves of the molecule. The Co(II) species disproportionate in non-coordinating solvents, in the presence of hydroxide ion, forming the potentially two-electron redox reagents Co(I) ;and Co(III)Pc. (Author)