Wang Ying, Gong Wen-Wen, Zhao Yan, Xing Guang-Yan, Kang Li-Xia, Sha Feng, Huang Zheng-Yang, Liu Jian-Wei, Han Yan-Jie, Li Peng, Li Deng-Yuan, Liu Pei-Nian
Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, State Key Laboratory of Chemical Engineering, School of Chemistry and Molecular Engineering, East China University of Science & Technology, Shanghai, 200237, P. R. China.
State Key Laboratory of Natural Medicines, Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing, 211198, P. R. China.
Angew Chem Int Ed Engl. 2024 Mar 11;63(11):e202318142. doi: 10.1002/anie.202318142. Epub 2024 Feb 6.
Precisely introducing topological defects is an important strategy in nanographene crystal engineering because defects can tune π-electronic structures and control molecular assemblies. The synergistic control of the synthesis and assembly of nanographenes by embedding the topological defects to afford two-dimensional (2D) crystals on surfaces is still a great challenge. By in-situ embedding ladder bipyrazinylene (LBPy) into acene, the narrowest nanographene with zigzag edges, we have achieved the precise preparation of 2D nonbenzenoid heteroacene crystals on Au(111). Through intramolecular electrocyclization of o-diisocyanides and Au adatom-directed [2+2] cycloaddition, the nonbenzenoid heteroacene products are produced with high chemoselectivity, and lead to the molecular 2D assembly via LBPy-derived interlocking hydrogen bonds. Using bond-resolved scanning tunneling microscopy, we determined the atomic structures of the nonbenzenoid heteroacene product and diverse organometallic intermediates. The tunneling spectroscopy measurements revealed the electronic structure of the nonbenzenoid heteroacene, which is supported by density functional theory (DFT) calculations. The observed distinct organometallic intermediates during progression annealing combined with DFT calculations demonstrated that LBPy formation proceeds via electrocyclization of o-diisocyanides, trapping of heteroarynes by Au adatoms, and stepwise elimination of Au adatoms.
精确引入拓扑缺陷是纳米石墨烯晶体工程中的一项重要策略，因为缺陷可以调节π电子结构并控制分子组装。通过嵌入拓扑缺陷来协同控制纳米石墨烯的合成与组装，从而在表面上获得二维（2D）晶体，仍然是一个巨大的挑战。通过将梯形联吡嗪（LBPy）原位嵌入到具有锯齿形边缘的最窄纳米石墨烯并四苯中，我们在Au(111)上实现了二维非苯并类杂并四苯晶体的精确制备。通过邻二异腈的分子内电环化反应和金吸附原子导向的[2+2]环加成反应，以高化学选择性生成了非苯并类杂并四苯产物，并通过LBPy衍生的互锁氢键导致分子二维组装。使用键分辨扫描隧道显微镜，我们确定了非苯并类杂并四苯产物和各种有机金属中间体的原子结构。隧道光谱测量揭示了非苯并类杂并四苯的电子结构，这得到了密度泛函理论（DFT）计算的支持。在逐步退火过程中观察到的不同有机金属中间体与DFT计算相结合表明，LBPy的形成是通过邻二异腈的电环化反应、金吸附原子捕获杂芳烃以及逐步消除金吸附原子来进行的。
