Zinc(II)-phenoxyl radical complexes: Dependence on complexation properties of Zn-phenolate species

Zn(II) complexes of three N3O-donor tripodal ligands with a phenol moiety were synthesized and characterized. The stability constants of the Zn(II)-ligand complexes decreased with the number of the 2-methylpyridine moieties replacing the unsubstituted pyridine rings as N donors. Upon one-electron oxidation the complexes gave the corresponding Zn(II)-phenoxyl radical species, whose half-life increased with the increase of the N-donor ability of the ligands in line with the stability relationship.