Fabrication of surface-confined ferrocene-appended cyclodextrins on gold electrode

Two β-cyclodextrin (β-CyD) derivatives, having both ferrocene and ethylmethylsulfide moieties, were synthesized. They spontaneously adsorbed onto a gold surface, which was characterized by linear relationship between the anodic peak current and potential sweep rate in the cyclic voltammograms obtained with the modified gold electrodes. The anodic and cathodic peak positions of the surface-confined ferrocene species were not identical, which indicates that the electrode reactions of the ferrocene species were depressed, probably due to the intramolecular complexation with their CyD cavities. Cyclic voltammometric studies with soluble electroactive probes (Fe(CN6)3− and ferrocenecarboxylic acid) revealed that the two β-CyD derivatives formed CyD monolayers with different permeability to each other.