1. Mechanistic Picture and Kinetic Analysis of Surface-Confined Ullmann Polymerization
- Author
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Di Giovannantonio, Tomellini, Lipton-Duffin, Galeotti, Ebrahimi, Cossaro, Verdini, Kharche, Meunier, Vasseur, Fagot-Revurat, Perepichka, D.F., Rosei, Contini, Di Giovannantonio, M., Tomellini, M., Lipton-Duffin, J., Galeotti, G., Ebrahimi, M., Cossaro, A., Verdini, A., Kharche, N., Meunier, V., Vasseur, G., Fagot-Revurat, Y., Perepichka, D. F., Rosei, F., and Contini, G.
- Subjects
polymer ,X ray photoelectron spectroscopy ,02 engineering and technology ,010402 general chemistry ,Kinetic energy ,01 natural sciences ,Biochemistry ,DFT ,Catalysis ,Ullmann reaction ,law.invention ,Ullmann coupling ,Colloid and Surface Chemistry ,X-ray photoelectron spectroscopy ,law ,behavior ,density functional theory ,geometry ,kinetics ,landscape ,polymerization ,scanning tunneling microscopy ,XPS ,ullmann ,Settore CHIM/03 - Chimica Generale e Inorganica ,Chemistry ,4-Dibromobenzene ,Conjugated structures ,Graphene nanoribbons ,Kinetic measurement ,Nucleation and growth ,Polymeric structures ,Polymerization process ,Surface polymerization ,General Chemistry ,Rate equation ,Kinetic parameters ,Kinetic theory ,Kinetics ,Nanoribbons ,Organometallics ,Polymerization ,Scanning tunneling microscopy ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Chemical physics ,Density functional theory ,Physical chemistry ,Scanning tunneling microscope ,0210 nano-technology - Abstract
Surface-confined polymerization via Ullmann coupling is a promising route to create one- and two-dimensional covalent ?-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. ? 2016 American Chemical Society.
- Published
- 2016
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