Design of self-assembled monolayers that release attached groups using applied electrical potentials

This Letter describes the design of a self-assembled monolayer of alkanethiolates on gold that can release attached groups when an electrical potential is applied to the gold. The design is based on monolayers that present a catechol orthoformate group that undergoes an irreversible two-electron oxidation with simultaneous release of the orthoformate substituent. Cyclic voltammograms (0.15 M NaCl, pH 7.4, 50 mV/s) of a monolayer presenting catechol orthoformate and hydroxyl groups showed an oxidation wave at 900 mV (versus Ag wire pseudo reference) for the quantitative conversion of the orthoformate group to the corresponding orthoquinone. The second cycle showed an oxidation wave at -75 mV and a reduction wave at -125 mV for the reversible oxidation of the catechol group.