title: Coexistence of one- and two-dimensional supramolecular assemblies of terephthalic acid on Pd(111) due to self-limiting deprotonation.
abstract: The adsorption of terephthalic acid [C(6)H(4)(COOH)(2), TPA] on a Pd(111) surface has been investigated by means of scanning tunneling microscopy (STM), x-ray photoelectron spectroscopy, and near-edge x-ray absorption fine structure spectroscopy under ultrahigh vacuum conditions at room temperature. We find the coexistence of one- (1D) and two-dimensional (2D) molecular ordering. Our analysis indicates that the 1D phase consists of intact TPA chains stabilized by a dimerization of the self-complementary carboxyl groups, whereas in the 2D phase, consisting of deprotonated entities, the molecules form lateral ionic hydrogen bonds. The supramolecular growth dynamics and the resulting structures are explained by a self-limiting deprotonation process mediated by the catalytic activity of the Pd surface. Our models for the molecular ordering are supported by molecular mechanics calculations and a simulation of high resolution STM images.
authors.affiliation: Institut de Physique des Nanostructures, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland. marta.canasventura@empa.ch
authors.forename: M E
authors.initials: ME
authors.lastname: Cañas-Ventura
authors.forename: F
authors.initials: F
authors.lastname: Klappenberger
authors.forename: S
authors.initials: S
authors.lastname: Clair
authors.forename: S
authors.initials: S
authors.lastname: Pons
authors.forename: K
authors.initials: K
authors.lastname: Kern
authors.forename: H
authors.initials: H
authors.lastname: Brune
authors.forename: T
authors.initials: T
authors.lastname: Strunskus
authors.forename: Ch
authors.initials: Ch
authors.lastname: Wöll
authors.forename: R
authors.initials: R
authors.lastname: Fasel
authors.forename: J V
authors.initials: JV
authors.lastname: Barth