title: Synthesis of Pyrene-Fused Pyrazaacenes on Metal Surfaces: Toward One-Dimensional Conjugated Nanostructures.
abstract: We investigated the synthesis of one-dimensional nanostructures via Schiff base (imine) formation on three close-packed coinage metal (Au, Ag, and Cu) surfaces under ultrahigh vacuum conditions. We demonstrate the feasibility of forming pyrene-fused pyrazaacene-based oligomers on the Ag(111) surface by thermal annealing of tetraketone and tetraamine molecules, which were designed to afford cyclocondensation products. Direct visualization by scanning tunneling microscopy of reactants, intermediates, and products with submolecular resolution and the analysis of their statistical distribution in dependence of stoichiometry and annealing temperature together with the inspection of complementary X-ray photoelectron spectroscopy signatures provide unique insight in the reaction mechanism, its limitations, and the role of the supporting substrate. In contrast to the reaction on Ag(111), the reactants desorb from the Au(111) surface before reacting, whereas they decompose on the Cu(111) surface during the relevant thermal treatment.
authors.affiliation: Physik-Department E20, Technische Universität München , James-Franck-Str. 1, D-85748 Garching, Germany.
authors.forename: Li
authors.initials: L
authors.lastname: Jiang
authors.affiliation: Physik-Department E20, Technische Universität München , James-Franck-Str. 1, D-85748 Garching, Germany.
authors.forename: Anthoula C
authors.initials: AC
authors.lastname: Papageorgiou
authors.affiliation: Physik-Department E20, Technische Universität München , James-Franck-Str. 1, D-85748 Garching, Germany.
authors.forename: Seung Cheol
authors.initials: SC
authors.lastname: Oh
authors.affiliation: Physik-Department E20, Technische Universität München , James-Franck-Str. 1, D-85748 Garching, Germany.
authors.forename: Özge
authors.initials: Ö
authors.lastname: Sağlam
authors.affiliation: Physik-Department E20, Technische Universität München , James-Franck-Str. 1, D-85748 Garching, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Reichert
authors.affiliation: Physik-Department E20, Technische Universität München , James-Franck-Str. 1, D-85748 Garching, Germany.
authors.forename: David A
authors.initials: DA
authors.lastname: Duncan
authors.affiliation: Physik-Department E20, Technische Universität München , James-Franck-Str. 1, D-85748 Garching, Germany.
authors.forename: Yi-Qi
authors.initials: YQ
authors.lastname: Zhang
authors.affiliation: Physik-Department E20, Technische Universität München , James-Franck-Str. 1, D-85748 Garching, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Klappenberger
authors.affiliation: Physik-Department E20, Technische Universität München , James-Franck-Str. 1, D-85748 Garching, Germany.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Physik-Department E20, Technische Universität München , James-Franck-Str. 1, D-85748 Garching, Germany.
authors.forename: Francesco
authors.initials: F
authors.lastname: Allegretti
authors.affiliation: POLYMAT, University of the Basque Country UPV/EHU , Avenida de Tolosa 72, E-20018 Donostia-San Sebastian, Spain.
authors.forename: Sandeep
authors.initials: S
authors.lastname: More
authors.forename: Rajesh
authors.initials: R
authors.lastname: Bhosale
authors.affiliation: POLYMAT, University of the Basque Country UPV/EHU , Avenida de Tolosa 72, E-20018 Donostia-San Sebastian, Spain.|Ikerbasque, Basque Foundation for Science, Bilbao, Spain.
authors.forename: Aurelio
authors.initials: A
authors.lastname: Mateo-Alonso
authors.affiliation: Physik-Department E20, Technische Universität München , James-Franck-Str. 1, D-85748 Garching, Germany.
authors.forename: Johannes V
authors.initials: JV
authors.lastname: Barth
keywords: STM; Schiff base; XPS; cyclocondensation; imine; ultrahigh vacuum