Properties and antioxidant activity of water-soluble iron catalysts with Schiff base ligands. Comparison with their manganese counterparts

Abstract

O), where 5-SO 3 -salpn = 1,3-bis(5-SO 3 -salicylidenamino)propane, 5-SO 3 -salpnOH = 1,3-bis(5-SO 3 -salicylidenamino)propan-2-ol and 5-SO 3 -sapentOH = 1,5-bis(5-SO 3 -salicylidenamino)pentan-3-ol, have been obtained and characterized. The ligands tune the redox potential of 1 and 2 within the range required for superoxide dismutase activity, with 2 being less reactive as a result of the formation of an inactive dimer. Complex 3 looses acetate and converts into a µ-oxo-Fe 2 species responsible for its catalase activity. The more negative reduction potentials of 1 -3 and their lower stability result in rates of superoxide and peroxide disproportionation 10-to 100-times slower than those of the Mn counterparts.