Reactions of a water soluble Cobalt Porphyrin with thiocyanate

Abstract

Rate and equilibrium constants have been determined for the reactions of Cobalt(III)Tetra(N-methyltetrapyridyl)Porphine with thiocyanate as a function of pH. The porphyrin ligand increases the substitution rates at the Co(III) center by several orders of magnitude relative to many other Co(III) complexes. The rates of formation and dissociation of the thiocyanate complexes are also dependent on the nature of the axial ligand trans to the water molecule being removed.