Unexpected adduct formation in the reaction of peroxomonosulfate ion with the tris-(2,2′-bipyridine)iron(II) and tris-(1,10-phenanthroline)iron(II) complexes

Abstract

Formation of 1 : 1 adduct intermediates was detected between peroxomonosulfate ion and tris-(2,2′-bipyridine)iron(II) or tris-(1,10-phenanthroline)iron(II) complexes. The formation equilibrium constants were determined (27 ± 3 and 63 ± 18 (mol L−1)−1) on the basis of kinetic measurements. The adduct was also detected by ESI mass spectrometry with the phenanthroline complex. A mechanism for the oxidation of tris-(2,2′-bipyridine)iron(II) or tris-(1,10-phenanthroline)iron(II) by peroxomonosulfate ion is proposed.