“Clicking” Functionality onto Electrode Surfaces

We demonstrate the applicability of Sharpless “click” chemistry, specifically Huisgen 1,3-dipolar cycloadditions, as a general methodology for functionalizing surfaces coated with self-assembled monolayers. Ferrocene immobilization was used as our model, and the resulting monolayers were analyzed using traditional surface analytical techniques. Our preliminary results indicate that this reaction proceeds to completion at room temperature in aqueous solvent. The triazole group is a thermally and hydrolytically stable, conjugated linkage. The reactants, acetylenes and azides, are independently stable; they do not react with common organic reagents or with themselves. Thus the potential for this reaction to immobilize a wide range of functionally complex substances on metal surfaces is significant. To our knowledge this is the first report of the use of “click” chemistry to modify a well-defined electrode surface.