Nickel Complexes as Antioxidants. Inhibition of Aldehyde Autoxidation by Nickel(II) Tetraazamacrocycles

Abstract

Nickel(II) cyclam and several other NiII complexes of tetraazamacrocyclic ligands were found to inhibit autoxidation of aldehydes. The NiII complexes that were effective had relatively low NiIII/NiII reduction potentials. Nickel(III) cyclam was found not to be an inhibitor. We propose that these NiII complexes terminate the free-radical chain reaction by trapping the intermediate acylperoxy radical.