Mixed-valence, tetranuclear cobalt(III, IV) complexes: preparation and properties of [Co4O4(O2CR)(2)(bpy) (4)](3+) salts

Cyclic voltammetric examination of [Co4O4(O2CR)(2)(bpy)(4)](ClO4)(2) cubane complexes 1 (R = various; bpy = 2,2'-bipyridine) in MeCN reveals a one-electron reversible oxidation in the range 0.68-0.86 V vs. ferrocene; the one-electron oxidized clusters can be obtained in analytical purity by either controlled potential electrolysis to give [Co4O4(O2CR)(2)(bpy)(4)](ClO4)(3) 2 or oxidation with (NH4)(2)Ce(NO3)(6) to give [Co4O4(O2CR)(2)(bpy)(4)][Ce(NO3)(6)] 3.