Although electrostatic bonding between chalcogen atoms and nitrogen has emerged as a powerful driving force in the fabrication of supramolecular structures, this noncovalent bond has not yet been used to link polymers to form networks. Taking advantage of additive enthalpy in forming multipoint noncovalent bonds, in this study we constructed a two-dimensional (2D) network via the hierarchical on-surface synthesis of linear polymer chains followed by multipoint S⋯N and S⋯H bonding. When 4,7-dibromobenzo[c][1,2,5]thiadiazole was used, only short oligomers with embedded bromine atoms and cross-linked byproducts were formed on Ag(111) or Au(111) surfaces after multiple annealing procedures, and no 2D network was observed. By changing the precursor to a similar iodine-substituted molecule, long linear polymers were generated and assembled with iodine atoms on Au(111) after annealing at 523 K. After annealing to 603 K, iodine atoms were desorbed and polymer chains were assembled via multipoint noncovalent bonding. The 2D network remained intact after annealing to 653 K, demonstrating its high thermostability. The multipoint noncovalent bonds were investigated by the combination of scanning tunneling microscopy, non-contact atomic force microscopy, and density functional theory calculations, which revealed that S⋯N and S⋯H bonding are the driving forces to construct thermostable and orderly 2D networks.

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中文翻译：

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通过多点 S⋯N 和 S⋯H 键合的二维网络的分层表面综合

尽管硫属原子和氮之间的静电键合已成为超分子结构制造中的强大驱动力，但这种非共价键尚未用于连接聚合物以形成网络。在本研究中，我们利用形成多点非共价键的加性焓，通过线性聚合物链的分层表面合成，然后进行多点 S⋯N 和 S⋯H 键合，构建了二维 (2D) 网络。当使用4,7-二溴苯并[ c ][1,2,5]噻二唑时，经过多次退火程序后，仅在Ag（111）或Au（111）表面上形成嵌入溴原子的短低聚物和交联副产物，并且没有观察到二维网络。通过将前体改为类似的碘取代分子，在 523 K 退火后生成长线性聚合物，并在 Au(111) 上与碘原子组装。退火至 603 K 后，碘原子解吸，通过多点组装聚合物链非共价键合。退火至 653 K 后，二维网络保持完整，证明了其高热稳定性。通过结合扫描隧道显微镜、非接触原子力显微镜和密度泛函理论计算对多点非共价键进行了研究，揭示了S⋯N和S⋯H键是构建热稳定有序二维网络的驱动力。

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