The flexibility of ligands allows for their bending, twisting, or rotation to adopt various conformations, leading to distinct symmetries during the self-assembled process. Flexible aromatic acid ligands modified by ether bonds are a promising type of self-assembled module when it comes to surfaces. Here, two pentacarboxylic acid ligands (H₅L1 and H₅L2) with minor skeleton differences have successfully self-assembled into disparate porous networks on the graphite surface and demonstrated excellent potential for the inclusion of guest molecules. The H₅L1 molecule’s network structure only accommodates coronene (COR) molecules. With fewer COR molecules, H₅L1 molecules act as a host template to accommodate the COR molecules. When there are too many COR molecules, COR molecules will induce H₅L1 molecules to transform into a new host–guest nanostructure. Additionally, H₅L2 molecules showed the ability to capture C₇₀ molecules and exhibited cavity selectivity. However, the assembled network of H₅L2 was slightly deformed in attempts to trap the COR molecules. To understand these phenomena more deeply, various assembled mechanisms were analyzed in combination with building theoretical models and energy analysis. These results reveal the great potential of flexible aromatic acid ligands in two-dimensional self-assembly and host–guest systems for their application in related fields.

中文翻译：

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醚键诱导的柔性五羧酸配体响应选择性客体包含的二维分子网络研究


配体的灵活性允许它们弯曲、扭曲或旋转以采用各种构象，从而在自组装过程中产生不同的对称性。当涉及表面时，通过醚键修饰的柔性芳香酸配体是一种有前途的自组装模块。在这里，具有较小骨架差异的两个五羧酸配体（H ₅ L1 和 H ₅ L2）已成功地在石墨表面自组装成不同的多孔网络，并表现出优异的应用潜力包含客体分子。 H ₅ L1 分子的网络结构仅容纳晕苯 (COR) 分子。由于 COR 分子较少，H ₅ L1 分子充当宿主模板来容纳 COR 分子。当COR分子过多时，COR分子会诱导H ₅ L1分子转变为新的主客体纳米结构。此外，H ₅ L2 分子表现出捕获 C ₇₀ 分子的能力并表现出空腔选择性。然而，H ₅ L2 的组装网络在尝试捕获 COR 分子时略有变形。为了更深入地理解这些现象，结合建立理论模型和能量分析，对各种组装机构进行了分析。这些结果揭示了柔性芳香酸配体在二维自组装和主客体系统中在相关领域应用的巨大潜力。