Ooe Hiroaki, Yokoyama Takashi
Faculty of Science, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027, Japan.
Phys Chem Chem Phys. 2024 May 1;26(17):12939-12946. doi: 10.1039/d4cp00696h.
Controlled bottom-up fabrication of molecular nanostructures through on-surface reactions of tailor-made precursors is of scientific and technological interest. Recently, on-surface polymerization reactions influenced by precursor self-assembly have been reported. Thus, a fundamental understanding of the reaction process is a prerequisite for controlled formation. Herein, we report on the influence of molecular self-assembly of dibrominated hexaphenylbenzene (Br-HPB) on the on-surface polymerization reactions on a Au(111) substrate. By using low-temperature scanning tunnelling microscopy (STM), we find that the polymerization of Br-HPB proceeds while maintaining the long-range ordered self-assembly, despite a decrease in HPB-HPB distance due to debromination and successive covalent bonding of Br-HPB. From the STM investigations of the polymerization process, we conclude that the polymerization of Br-HPB is accompanied by molecular rotations to maintain the periodic array of the self-assembled structure, contrary to the conventional understanding of the polymerization of the self-assembled precursor layer.
通过定制前体的表面反应自下而上可控地制备分子纳米结构具有科学和技术意义。最近，已有报道称前体自组装会影响表面聚合反应。因此，对反应过程的基本理解是实现可控形成的先决条件。在此，我们报道了二溴化六苯基苯（Br-HPB）的分子自组装对Au(111)衬底上表面聚合反应的影响。通过低温扫描隧道显微镜（STM），我们发现尽管由于脱溴和Br-HPB的连续共价键合导致HPB-HPB间距减小，但Br-HPB的聚合反应仍在进行，同时保持了长程有序的自组装结构。通过对聚合过程的STM研究，我们得出结论，与对自组装前体层聚合的传统理解相反，Br-HPB的聚合伴随着分子旋转以维持自组装结构的周期性排列。
