Kinetics of peroxodisulphate oxidation of low-spin iron(II) complexes in binary aqueous mixtures

Abstract

The kinetics of oxidation of two low-spin iron(II) complexes by peroxodisulphate in binary aqueous mixtures have been investigated. Rate constants for the oxidation of the [Fe(phen)₃]²⁺ cation (phen = 1,10-phenanthroline) are reported in mixtures containing up to 60% acetone or 40% dimethyl sulphoxide. Rate constants for the oxidation of the [Fe(bqdo)]²⁺ cation (bqdo = the sexidentate Schiff base derived from quinoline-2-carbaldehyde and triethylenetetramine) are reported in mixtures containing up to 40% acetone or dimethyl sulphoxide. Reactivity trends are discussed in terms of the variation of the chemical potentials of the reactants and of the transition state with solvent composition.