Grafting of ω-Alkyl Ferrocene Radicals to Carbon Surfaces By Means Of Electrocatalysis with Subnanomolar Transition-Metal (Pd, Pt, or Au) Layers

Abstract

Electroreduction of ω-iodoalkyl ferrocenes (Fc-Cn-I) was achieved in non-aqueous media at carbon electrodes covered with extremely small amounts of transition metals (Γ≤10−9 mol cm−2) galvanostatically deposited onto the surface. Upon such a coverage with metals such as palladium, gold, platinum, and rhodium, the cleavage of the CI bond becomes a one-electron process leading, within the potential range from −1.0 to −1.5 V vs. Ag/AgCl, to the formation of a free alkyl radical. The addition of these radicals onto the carbon surface may occur to a large extent at the graphitized zones (radical attack on C sites) and dense ferrocene layers, attached to the solid support by alkyl linkers, can thus be formed. Other metals such as copper, nickel, and cobalt were successfully used in this process. The residual metal deposits could be eliminated by simple sonication of the resulting carbon interfaces.