Self-exchange reactions of cobalt complexes and implications concerning redox reactivity of vitamin B12
Abstract
The self-exchange rates of Co(N4)(OH2)23+,2+ complexes, where (N4) is a tetradentate macrocyclic ligand, have been found to vary by a factor of 1010; the large reactivity range cannot be related to “spin effects”, but is likely a reflection of ligand reorganizational barriers; the vitamin B12a–B12r couple is at the high end of this range—a feature which has significance in the redox mechanisms of B12 and related systems.