title: Mechanistic Picture and Kinetic Analysis of Surface-Confined Ullmann Polymerization.
abstract: Surface-confined polymerization via Ullmann coupling is a promising route to create one- and two-dimensional covalent π-conjugated structures, including the bottom-up growth of graphene nanoribbons. Understanding the mechanism of the Ullmann reaction is necessary to provide a platform for rationally controlling the formation of these materials. We use fast X-ray photoelectron spectroscopy (XPS) in kinetic measurements of epitaxial surface polymerization of 1,4-dibromobenzene on Cu(110) and devise a kinetic model based on mean field rate equations, involving a transient state. This state is observed in the energy landscapes calculated by nudged elastic band (NEB) within density functional theory (DFT), which assumes as initial and final geometries of the organometallic and polymeric structures those observed by scanning tunneling microscopy (STM). The kinetic model accounts for all the salient features observed in the experimental curves extracted from the fast-XPS measurements and enables an enhanced understanding of the polymerization process, which is found to follow a nucleation-and-growth behavior preceded by the formation of a transient state.
authors.affiliation: Istituto di Struttura della Materia, CNR , Via Fosso del Cavaliere 100, 00133 Roma, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Di Giovannantonio
authors.affiliation: Istituto di Struttura della Materia, CNR , Via Fosso del Cavaliere 100, 00133 Roma, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Tomellini
authors.affiliation: Institute for Future Environments, Queensland University of Technology (QUT) , 2 George Street, Brisbane, Queensland 4001, Australia.
authors.forename: Josh
authors.initials: J
authors.lastname: Lipton-Duffin
authors.affiliation: Centre Énergie, Matériaux et Télécommunications, Institut National de la Recherche Scientifique , 1650 Boulevard Lionel-Boulet, Varennes, Quebec J3X 1S2, Canada.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Galeotti
authors.affiliation: Centre Énergie, Matériaux et Télécommunications, Institut National de la Recherche Scientifique , 1650 Boulevard Lionel-Boulet, Varennes, Quebec J3X 1S2, Canada.
authors.forename: Maryam
authors.initials: M
authors.lastname: Ebrahimi
authors.affiliation: CNR-IOM , Laboratorio TASC, 34149 Trieste, Italy.
authors.forename: Albano
authors.initials: A
authors.lastname: Cossaro
authors.affiliation: CNR-IOM , Laboratorio TASC, 34149 Trieste, Italy.
authors.forename: Alberto
authors.identifier: 0000-0001-8880-2080
authors.initials: A
authors.lastname: Verdini
authors.affiliation: Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute , 110 Eighth Street, Troy, New York 12180, United States.
authors.forename: Neerav
authors.initials: N
authors.lastname: Kharche
authors.affiliation: Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute , 110 Eighth Street, Troy, New York 12180, United States.
authors.forename: Vincent
authors.initials: V
authors.lastname: Meunier
authors.affiliation: Donostia International Physics Center (DIPC) , Paseo Manuel Lardizabal 4, 20018 San Sebastián, Spain.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Vasseur
authors.affiliation: Institut Jean Lamour, UMR 7198, Université de Lorraine/CNRS , B.P. 70239, Vandoeuvre-Les-Nancy F-54506, France.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Fagot-Revurat
authors.affiliation: Department of Chemistry, McGill University , 801 Sherbrooke Street, West Montreal, Quebec H3A 0B8, Canada.
authors.forename: Dmitrii F
authors.initials: DF
authors.lastname: Perepichka
authors.affiliation: Centre Énergie, Matériaux et Télécommunications, Institut National de la Recherche Scientifique , 1650 Boulevard Lionel-Boulet, Varennes, Quebec J3X 1S2, Canada.|Institute for Fundamental and Frontier Science, University of Electronic Science and Technology of China , Chengdu 610054, PR China.
authors.forename: Federico
authors.initials: F
authors.lastname: Rosei
authors.affiliation: Istituto di Struttura della Materia, CNR , Via Fosso del Cavaliere 100, 00133 Roma, Italy.
authors.forename: Giorgio
authors.identifier: 0000-0002-6248-9716
authors.initials: G
authors.lastname: Contini