Ferrocenylated gold nanoparticles self-assemble at carbon surfaces to form stable films

It is well known that thiols, dithiols and other thiolated species adsorb easily on gold surfaces but they do not adsorb on carbon electrodes. Interestingly, when the same ferrocene thiol is bound to a gold nanoparticle, the adsorption at carbon surfaces becomes very strong. Electrochemical behaviour of ferrocenylated nanoparticles adsorbed on carbon electrodes is similar to that of a thiol derivative chemically bound to gold electrode by means of strong covalent gold-sulphur bond. In the presence of 11-(ferrocenyl)undecanethiol-functionalized gold nanoparticles (FUT@AuNPs) in the solution, the adsorptive voltammetric peaks registered at glassy carbon electrode become narrow pointing to the contribution of strong attractive interactions in the adsorbed layer. Atomic force microscopy confirmed the strong adsorption on highly oriented pyrolytic graphite and deformation of the nanoparticle ligands at the hydrophobic carbon surfaces.