Organized self‐assembled lipoyl‐β‐cyclodextrin derivative monolayer on a gold electrode

An organized self‐assembled monolayer of β‐cyclodextrin (β‐CD) derivatives on a gold surface has been prepared using two lipoyl‐β‐cyclodextrin derivatives with different chain lengths, which are more flexible than heptakis (dodecyl sulfide) β‐cyclodextrin. The surface coverage of the monolayers were found to be in agreement with the surface coverage of a highly organized monolayer of β‐CD. It has been revealed by cyclic voltammetry that the β‐CD derivative monolayers have the characteristics of: (a) selective barriers blocking the permeability for those molecules, such as ferricyanide, and p ‐aminophenol, which are incapable of complexing with β‐CD; and (b) have selective transport for electroactive organic species, such as ferrocene carboxylic acid and hydroxyquinone, which can form host‐guest inclusion complexes with β‐CD receptors. The selective transport can be controlled by blocking the β‐CD cavities with some guest molecules such as cyclohexanol borneol and ursodeoxycholic acid, and the controlling mode can be expected for detection of organic compounds.