Surface-Confined Polymerization of Halogenated Polyacenes: The Case of Dibromotetracene on Ag(110)

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• 作者：Igor Píš ; Lara Ferrighi ; Thanh Hai Nguyen ; Silvia Nappini ; Luca Vaghi ; Andrea Basagni ; Elena Magnano ; Antonio Papagni ; Francesco Sedona ; Cristiana Di Valentin ; Stefano Agnoli ; Federica Bondino
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：March 10, 2016
• 年：2016
• 卷：120
• 期：9
• 页码：4909-4918
• 全文大小：613K
• ISSN：1932-7455

文摘

On-surface synthesis of thin organic and organometallic films in a bottom-up fashion has become a promising approach for the development of new nanotechnologies. In this work we studied 5,11-dibromotetracene (C₁₈H₁₀Br₂) as a prototypical case of rodlike polyaromatic molecules functionalized with two bromine atoms on the sides. The adsorption and temperature-stimulated transformations of dibromotetracene assemblies on Ag(110) have been investigated by a combination of synchrotron radiation X-ray photoemission spectroscopy (XPS), near-edge X-ray absorption spectroscopy (NEXAFS), scanning tunneling microscopy (STM), and density functional theory (DFT) calculations. Upon the contact with the Ag substrate, the Br–C bonds are promptly cleaved at room temperature, and Ag-coordinated protopolymers are formed along the [001] substrate direction. The organometallic dimers and trimers remain on the surface up to 523 K. The stabilization of the protopolymers is driven by the substrate anisotropy and weak interactions with nearby Br atoms. The short oligomers formed at elevated temperatures are weakly bounded to the substrate and desorb before covalent structures can be formed.