Charge transfer processes in bilayers and co-polymers composed of C60Pd and 2′-ferrocenylpyrrolidino-[3′,4′;1,2]C60Pd two-component polymers

Abstract

Bilayers composed of fullerene based polymers, C60Pd (n-doped system) and 2′-ferrocenylpyrrolidino-[3′,4′;1,2]C60Pd, Fc-C60Pd, (n- and p-doped system) were prepared by sequential electro-deposition of the parent monomers. The bilayer electrode processes depend upon the polymerization sequence. For the electrode–Fc-C60Pd–C60Pd system, where Fc-C60Pd is initially deposited on the surface and then a layer of C60Pd is deposited, the processes of both fullerene reduction and ferrocene oxidation are observed. The high permeability of the C60Pd film to the ions of the supporting electrolyte allows the oxidation of the inner Fc-C60Pd layer. In the case of the bilayer electrode–C60Pd–Fc-C60Pd, the C60Pd layer is not conductive in the potential range of ferrocene group oxidation. Consequently, the inner C60Pd film inhibits the process of outer layer oxidation. Incorporation of metallic palladium particles into the inner C60Pd layer results in an increase in that film's conductivity. With a C60Pd layer containing metallic palladium particles, the outer Fc-C60Pd layer of the bilayer electrode–C60Pd–Fc-C60Pd can be oxidized at positive potentials. In acetonitrile–toluene containing Pd(ac)2 and both C60 and Fc-C60, a C60Pd-co-Fc-C60Pd co-polymer is formed during electro-reduction at the electrode surface. This film exhibits redox activity both in the negative and positive potential ranges.