Dimerization, redox properties and antioxidant activity of two manganese(III) complexes of difluoro- and dichloro-substituted Schiff-base ligands

[Mn(3,5-F2salpn)]+ and [Mn(3,5-Cl2salpn)(OAc)] catalyze H2O2 disproportionation through a cycle involving MnIII2 and MnIV2 dimers, unlike related complexes with a more rigid and smaller chelate ring that employ MnIII/MnVO monomers. While [Mn(3,5-F2salpn)]+ shows catalase activity higher than the 3,5-Cl2-substituted complex, the phenyl-ring substituent has little effect on superoxide dismutase activity.88