Voltammetric study of electron transfer across the 1,6-dichlorohexane|water interface with the bis(pentamethylcyclopentadienyl)iron(II/III) redox couple

The electron transfer reaction across the 1,6-dichlorohexane (1,6-DCH)|water (W) interface where bis(pentamethylcyclopentadienyl)iron(II/III) ([FeII/III(C5Me5)2]0/+) as the organic redox couple in 1,6-DCH is present in excess has been studied by cyclic voltammetry. The 1,6-DCH|W interface gave a potential window where the transfer of [FeIII(C5Me5)2]+ ion as well as that of [FeII(C5Me5)2]0 across the interface can be neglected. When hexaammineruthenium(III) and cyano complexes of iron protoporphyrin IX and microperoxidase-11, which do not transfer across the 1,6-DCH|W interface in the potential range tested, are present in W as the aqueous reactant, well-defined voltammetric waves due to the heterogeneous electron transfer have been observed within the potential window. The voltammetric waves can be assigned to reversible one-electron transfer controlled by diffusion of the aqueous redox couple in W. The reversible half-wave potentials are consistent with those predicted from simple voltammetric experiments with a Pt electrode.