The stabilization of high oxidation states of metals through coordination by poly-aza macrocycles

A review with 42 refs. The tendency to stabilize trivalent cations, which is expressed by the value of the M3+/M2p redox potential (M = Cu, Ni, etc.), is regulated by the structural features of the macrocycle (ring size, no. and type of donor N atm.). Axial coordination of the solvent, equatorial interactions, and ligand field contributions are discussed