Oligourea molecular lifter triggered by electric field

Abstract

We have synthesized an oligourea foldamer containing seven urea residues, with a Cys-like residue introduced near the N-terminus of the helix. This enabled the immobilization of the molecules on gold electrode using gold-sulfur chemistry. Molecular layer was characterized by electrochemical and spectroelectrochemical methods. Electrochemical measurements confirmed the formation of a dielectric layer on the electrode surface and the determined potential of zero free charge proved that the molecules are adsorbed with the positive pole of the dipole pointing to the electrode surface. The measurements with the use of in situ surface-enhanced infrared absorption spectroscopy provided insight into the dynamics of molecules under the influence of the electric field. Namely, helical oligourea molecules undergo reversible potential-induced changes in the orientation of the molecules. Our results show that molecular layers of oligourea helical foldamers can be used as building blocks for assembly of stimuli-responsive molecular layers serving as molecular lifters triggered by electric field.