卤素-原子介导的金属表面二维分子自组装相变,Langmuir

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卤素-原子介导的金属表面二维分子自组装相变
Langmuir ( IF 3.7 ) Pub Date : 2017-12-28 00:00:00 , DOI: 10.1021/acs.langmuir.7b03796
Tianchao Niu ₁ , Jinge Wu ₂ , Faling Ling ₃ , Shuo Jin ₂ , Guanghong Lu ₂ , Miao Zhou ₂

Affiliation

在宏观尺度上构建具有所需晶格和功能的可调谐且健壮的二维（2D）分子阵列，取决于合适的分子之间的自发性和可逆非共价相互作用，它们是构件。卤素键具有方向，强度和长度的主动可调性，是定制超分子结构的理想选择。在这里，通过结合低温扫描隧道显微镜和系统的第一性原理计算，我们证明了涉及单个卤素原子的新型卤素键和二维分子自组装中的相工程。在Au（111）表面上，我们观察到六溴苯（HBB）分子的催化脱卤作用，其间带负电荷的溴原子（^Brδ-）是通过独特的C–Brδ ⁺ ··· ^Brδ-相互作用生成并参与组装的，这与化学惰性石墨烯基底上的HBB组装有很大不同。我们成功地绘制了组装后的上部结构的不同相，包括分别在室温，60°C，90°C和110°C下紧密堆积的六角形，四角形，二聚体链和膨胀的六角形晶格，以及溴的关键作用突出了调节晶格特性中的^δ-。我们的研究结果显示，有望为分子纳米电子学和2D晶体工程的未来发展操纵非共价相互作用和催化反应之间的相互作用。

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Halogen-Adatom Mediated Phase Transition of Two-Dimensional Molecular Self-Assembly on a Metal Surface

Construction of tunable and robust two-dimensional (2D) molecular arrays with desirable lattices and functionalities over a macroscopic scale relies on spontaneous and reversible noncovalent interactions between suitable molecules as building blocks. Halogen bonding, with active tunability of direction, strength, and length, is ideal for tailoring supramolecular structures. Herein, by combining low-temperature scanning tunneling microscopy and systematic first-principles calculations, we demonstrate novel halogen bonding involving single halogen atoms and phase engineering in 2D molecular self-assembly. On the Au(111) surface, we observed catalyzed dehalogenation of hexabromobenzene (HBB) molecules, during which negatively charged bromine adatoms (Br^δ−) were generated and participated in assembly via unique C–Br^δ+···Br^δ− interaction, drastically different from HBB assembly on a chemically inert graphene substrate. We successfully mapped out different phases of the assembled superstructure, including densely packed hexagonal, tetragonal, dimer chain, and expanded hexagonal lattices at room temperature, 60 °C, 90 °C, and 110 °C, respectively, and the critical role of Br^δ− in regulating lattice characteristics was highlighted. Our results show promise for manipulating the interplay between noncovalent interactions and catalytic reactions for future development of molecular nanoelectronics and 2D crystal engineering.

更新日期：2017-12-28

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