芳基氯在Ag(111)上的脱氯乌尔曼偶联反应：扫描隧道显微镜与X射线光电子能谱的联合研究
Dechlorinated Ullmann Coupling Reaction of Aryl Chlorides on Ag(111): A Combined STM and XPS Study.
作者信息
Dai Jingxin, Zhao Wenhui, Xing Lingbo, Shang Jian, Ju Huanxin, Zhou Xiong, Liu Jing, Chen Qiwei, Wang Yongfeng, Zhu Junfa, Wu Kai
机构信息
BNLMS, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.
National Synchrotron Radiation Laboratory and Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science and Technology of China, Hefei, 230029, China.
出版信息
Chemphyschem. 2019 Sep 17;20(18):2367-2375. doi: 10.1002/cphc.201900264. Epub 2019 Jul 16.
Surface-assisted Ullmann coupling was widely applied to construct various molecular nanostructures on surfaces due to its reliability and controllability. By using 4,4''-dichloro-1,1':3',1''-terphenyl (DCTP) as the precursor, covalently bonded zig-zag oligophenylene chains and hexagonal hyperbenzene rings, e. g., [18]-honeycombenes, were successfully fabricated on Ag(111) via dechlorinated Ullmann coupling reaction. Stepwise annealing was applied to investigate the reaction process in detail. Scanning tunneling microscopy and synchrotron X-ray photoemission spectroscopy were utilized to explore the thermal evolution of the DCTP molecules on Ag(111) under ultrahigh vacuum conditions, evidencing the existence of intact DCTP molecules, chemisorbed Cl atoms, covalently bonded DCTP dimers as well as organometallic C-Ag-C-containing intermediates. These results may help understand dechlorinated Ullmann coupling reaction of aryl chlorides on metal surfaces.
表面辅助乌尔曼偶联由于其可靠性和可控性，被广泛应用于在表面构建各种分子纳米结构。通过使用4,4''-二氯-1,1':3',1''-三联苯（DCTP）作为前体，经由脱氯乌尔曼偶联反应，在Ag(111)上成功制备了共价键合的锯齿状低聚苯撑链和六边形超苯环，例如[18]-蜂窝烯。采用逐步退火来详细研究反应过程。利用扫描隧道显微镜和同步辐射X射线光电子能谱，在超高真空条件下探索DCTP分子在Ag(111)上的热演化，证明存在完整的DCTP分子、化学吸附的Cl原子、共价键合的DCTP二聚体以及含C-Ag-C的有机金属中间体。这些结果可能有助于理解芳基氯化物在金属表面的脱氯乌尔曼偶联反应。
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