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

Two beta -cyclodextrin (beta -CyD) derivatives, having both ferrocene and e thylmethylsulfide moieties, were synthesized. They spontaneously adsorbed o nto a gold surface, which was characterized by linear relationship between the anodic peak current and potential sweep rate in the cyclic voltammogram s obtained with the modified gold electrodes. The anodic and cathodic peak positions of the surface-confined ferrocene species were not identical, whi ch indicates that the electrode reactions of the ferrocene species were dep ressed, probably due to the intramolecular complexation with their CyD cavi ties. Cyclic voltammometric studies with soluble electroactive probes (Fe(C N6)(3-) and ferrocenecarboxylic acid) revealed that the two beta -CyD deriv atives formed CyD monolayers with different permeability to each other. (C) 2001 Elsevier Science B.V. All rights reserved.