FORMATION AND DISSOCIATION EQUILIBRIA OF INTERMEDIATE SPECIES IN THE OXIDATION OF COBALT(II)-DIPEPTIDE COMPLEXES

The oxidation of various cobalt(II)-dipeptide complexes in the presence of both molecular oxygen and hydrogen peroxide is examined. The nature of the oxidant exercises a marked influence on the reaction path. The oxointermediate species formed apparently possesses different structures, depending on the oxidant. Moreover, when molecular oxygen is employed, the inertness of the resulting cobalt(III)-dipeptide complexes is much higher, suggesting a different degree of protonation. The effect of the ligand structure on the oxidative process is considered; the reaction rate is found to be strongly influenced by the hydrophobicity of the substituent group and by the presence of amidic hydrogen.