Wang Zhengya, Yin Ruoting, Meng Jie, Wang Jianing, Liang Yifan, Ma Chuanxu, Tan Shijing, Li Qunxiang, Yang Jinlong, Wang Bing
Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China.
J Am Chem Soc. 2023 Apr 4. doi: 10.1021/jacs.3c00111.
Because of their theoretically predicted intriguing properties, it is interesting to embed periodic 585-ringed divacancies into graphene nanoribbons (GNRs), but it remains a great challenge. Here, we develop an on-surface cascade reaction from periodic hydrogenated divacancies to alternating 585-ringed divacancies and Ag atoms via intramolecular cyclodehydrogenation in a seven-carbon-wide armchair GNR on the Ag(111) surface. Combining scanning tunneling microscopy/spectroscopy and noncontact atomic force microscopy combined with first-principles calculations, we in-situ-monitor the evolution of the distinct structural and electronic properties in the reaction intermediates. The observation of embedded Ag atoms and further nudged elastic band calculations provide unambiguous evidence for Ag adatom-mediated C-H activation in the intramolecular cyclodehydrogenation pathway, where the strain-induced self-limiting effect contributes to the formation of the GNR superlattice with alternating 585-ringed divacancies and Ag atoms, which shows a band gap of about 1.4 eV. Our findings open an avenue to introducing periodic impurities of single metal atoms and nonhexagonal rings in on-surface synthesis, which may provide a novel route for multifunctional graphene nanostructures.
由于其理论预测的有趣性质，将周期性的585环双空位嵌入石墨烯纳米带（GNRs）中很有意思，但这仍然是一个巨大的挑战。在此，我们在Ag(111)表面的七碳宽扶手椅型GNR中，通过分子内环化脱氢反应，开发了一种从周期性氢化双空位到交替的585环双空位和Ag原子的表面级联反应。结合扫描隧道显微镜/光谱和非接触原子力显微镜以及第一性原理计算，我们原位监测了反应中间体中独特的结构和电子性质的演变。嵌入Ag原子的观察结果以及进一步的推挤弹性带计算为分子内环化脱氢途径中Ag吸附原子介导的C-H活化提供了明确的证据，其中应变诱导的自限效应有助于形成具有交替的585环双空位和Ag原子的GNR超晶格，其带隙约为1.4 eV。我们的发现为在表面合成中引入单金属原子和非六边形环的周期性杂质开辟了一条途径，这可能为多功能石墨烯纳米结构提供一条新的路线。
