The effect of non-ionic micelles on the kinetics of the electron-transfer reactions of iron(III) with substituted ferrocenes

Abstract

The effect of five non-ionic surfactants of the type n-alkylpoly(oxyethylene glycol) monoether on the kinetics of the electron-transfer reactions of the iron(III) ion with ferrocene and its n-butyl, 1,1′-dimethyl and 1,1′-di-n-butyl derivatives has been studied at 20.0 °C and ionic strength 0.02 mol dm^–3. All the non-ionic micelles retard the electron-transfer reaction; the inhibiting micellar effects are markedly dependent on the hydrophobicity of the reducing species and, to a lesser extent, on the type of the micelle-forming surfactant. The reactivity data, the estimated binding constants and the standard transfer free energies of the ferrocenes from water to the micelle suggest that binding of the solubilizates occurs in the hydrocarbon interior of the micelle.