Spectroscopic evidence for non-planarity in nickel(III) complexes of macrocyclic ligands. Pulse radiolysis and electron spin resonance studies in aqueous solution

Abstract

The spectral and e.s.r. data obtained from the reaction of Ni^II macrocyclic with OH˙ radicals in aqueous solution show that oxidation takes place at the metal centre to form momentarily stable Ni^III species, and, depending on the degree of unsaturation in the ligand employed, strong absorption bands in the region associated with d–d transitions can occur which may be best explained by departures from planarity in the complex.