A study of the electron-transfer reaction between Fe(CN)2(bpy)2 and S2O82- in solvent mixtures: the translational component of solvent reorganization

Abstract

The kinetics of the oxidation of dicyanobis(2,2′-bipyridine) iron(II) [Fe(CN)₂(bpy)₂] by peroxodisulfate (S₂O₈^2-) has been studied in different water–cosolvent mixtures. The cosolvents used were methanol, tert-butyl alcohol, ethylene glycol and glycerol. The results are explained assuming an additional component of the reorganization free energy of the solvent in the mixtures, caused by a translation of the solvent molecules, as a consequence of the changes in the composition of the (at least) innermost solvation shell. A quantitative estimation of this component is attempted.