title: Potential-induced structure changes of oligopyridine adlayers on Au(111) electrodes.
abstract: The structure of a bisterpyridine-like oligopyridine (abbreviated as 2,4'-BTP) monolayer on Au(111), adsorbed from an acetone solution, was studied by in situ scanning tunneling microscopy and cyclic voltammetry in aqueous 0.1 M H2SO4. Short-range ordered adsorption with an average distance between the individual molecules of about 2 nm was observed only at electrode potentials positive of +0.4 V vs SCE, whereas at more negative potentials, no order could be found. With the help of Cu underpotential deposition, a potential-induced, fast, and fully reversible structure transition within the organic monolayer was identified at about +0.4 V vs SCE. At negative potentials the molecules apparently cluster together and consequently current-potential curves resemble those for a bare gold surface, whereas for E>+0.4 V vs SCE the molecules are spread over the entire surface in a hexagonal, close-packed fashion. This may have interesting consequences for switching between different template structures.
authors: Institute of Organic Chemistry III, University of Ulm, 89069 Ulm, Germany.
authors: Yangguang
authors: Y
authors: Dai
authors: Christoph
authors: C
authors: Meier
authors: Ulrich
authors: U
authors: Ziener
authors: Katharina
authors: K
authors: Landfester
authors: Corina
authors: C
authors: Täubert
authors: Dieter M
authors: DM
authors: Kolb