Surface-Confined Polymerization of Halogenated Polyacenes: The Case of Dibromotetracene on Ag(110)
Surface-Confined Polymerization of Halogenated Polyacenes: The Case of Dibromotetracene on Ag(110)
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DOI：
10.1021/acs.jpcc.5b12047
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发表时间：
2016-03-10
影响因子：
3.7
通讯作者：
Bondino, Federica
中科院分区：
文献类型：
--
作者：
Pis, Igor;Ferrighi, Lara;Bondino, Federica
以自下而上的方式在表面合成有机和有机金属薄膜已成为开发新纳米技术的一种有前途的方法。在这项工作中，我们研究了 5,11-二溴四苯 (C18H10Br2)，作为侧面用两个溴原子官能化的棒状聚芳烃分子的典型案例。通过结合同步辐射X射线光电子能谱（XPS）、近边X射线吸收光谱（NEXAFS）、扫描隧道显微镜（STM）和密度泛函理论（DFT）计算，研究了Ag（110）上二溴四苯组件的吸附和温度刺激转变。当与Ag基底接触时，Br-C键在室温下迅速断裂，并沿[001]基底方向形成Ag配位原聚物。在高达 523 K 的温度下，有机金属二聚体和三聚体仍保留在表面。原聚物的稳定性是由基底的各向异性以及与附近 Br 原子的弱相互作用驱动的。在高温下形成的短低聚物与基材的结合较弱，并在形成共价结构之前解吸。
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 diners 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.