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Structural Transformation of 2,7-Dibromopyrene on Au(111) Mediated by Halogen-Bonding Motifs |
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| Authors: | Jinbang Hu Kongchao Shen Jinping Hu Haoliang Sun Qiwei Tian Zhaofeng Liang Han Huang Prof Zheng Jiang Prof Justin W Wells Prof Fei Song |
| Institution: | 1. Key Laboratory of Interfacial Physics and Technology and Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201204 China
University of Chinese Academy Sciences, Beijing, 101000 China;2. Key Laboratory of Interfacial Physics and Technology and Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201204 China;3. Key Laboratory of Interfacial Physics and Technology and Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201204 China School of Physics Science and Electronics, Central South University, Changsha, 410083 China;4. School of Physics Science and Electronics, Central South University, Changsha, 410083 China;5. Key Laboratory of Interfacial Physics and Technology and Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201204 China University of Chinese Academy Sciences, Beijing, 101000 China Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201210 China;6. Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, Trondheim, NO-7491 Norway |
| Abstract: | Fundamental understanding of the bonding motifs that elaborately mediate the formation of supramolecular nanostructures is essential for the rational design of stable artificial organic architectures. Herein, the structural transformation of the adsorption complex of 2, 7-dibromopyrene (Br2Py) on the Au(111) surface has been investigated by scanning tunnelling microscopy combined with X-ray photoemission spectroscopy and density function theory calculations. In the initial stage of self-assembly, well ordered patterns are formed in the manner of extended supramolecular structures balanced by intermolecular halogen bonding motifs, whilst the Au(111) reconstruction is still fairly visible. Subsequent thermal annealing promotes the dehalogenation and on-surface Ullmann coupling, and polymerized oligomers are consequently constructed. Interestingly, such polymerized chains are still stably mediated by the halogen bonding motif via dissociated Br atoms which are revealed to be absorbed on the bridge site of Au(111), while the number of halogen bonds increases significantly from self-assembly to Ullmann coupling polymerization, indicating that the halogen bonding motif contributes significantly to the extended one-dimensional polymers. |
| Keywords: | gold halogen bonding self-assembly STM Ullmann coupling |