Competition between Hexagonal and Tetragonal Hexabromobenzene Packing on Au(111)
| Autor: | Guo Tian, Zhenhong Zhou, Han Huang, Kang Zhao, Tan Zhiyu, Jia-Tao Sun, Yanwei He, Jian Liu, Swee Liang Wong, Andrew T. S. Wee |
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| Rok vydání: | 2016 |
| Předmět: |
Halogen bond
Materials science Intermolecular force General Engineering General Physics and Astronomy Nanotechnology 02 engineering and technology Substrate (electronics) 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences law.invention Crystallography Tetragonal crystal system chemistry.chemical_compound chemistry law Hexabromobenzene Molecule General Materials Science Density functional theory Scanning tunneling microscope 0210 nano-technology |
| Zdroj: | ACS nano. 10(3) |
| ISSN: | 1936-086X |
| Popis: | Low-temperature scanning tunneling microscope investigations reveal that hexabromobenzene (HBB) molecules arrange in either hexagonally closely packed (hcp) [Formula: see text] or tetragonal [Formula: see text] structure on Au(111) dependent on a small substrate temperature difference around 300 K. The underlying mechanism is investigated by density functional theory calculations, which reveal that substrate-mediated intermolecular noncovalent C-Br···Br-C attractions induce hcp HBB islands, keeping the well-known Au(111)-22×√3 reconstruction intact. Upon deposition at 330 K, HBB molecules trap freely diffusing Au adatoms to form tetragonal islands. This enhances the attraction between HBB and Au(111) but partially reduces the intermolecular C-Br···Br-C attractions, altering the Au(111)-22×√3 reconstruction. In both cases, the HBB molecule adsorbs on a bridge site, forming a ∼15° angle between the C-Br direction and [112̅]Au, indicating the site-specific molecule-substrate interactions. We show that the competition between intermolecular and molecule-substrate interactions determines molecule packing at the subnanometer scale, which will be helpful for crystal engineering, functional materials, and organic electronics. |
| Databáze: | OpenAIRE |
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