关键词: 超分子聚合物, 柱[5]芳烃, 镧系发光, 荧光探针, 铜离子

In recent years, supramolecular polymers constructed in the participation of lanthanide metal coordination commonly combine excellent luminescence properties with dynamic reversibility, have been widely reported for designing or developing intelligent sensing materials. In this paper, a bridged bis-pillar[5]arene macrocyclic molecule was synthesized in one step by the bicyclic oligomerization method. This strategy was proved to be a convenient and efficient synthesis path for pillararene dimers. Due to its double-ring cavities, this macrocyclic molecule is highly suitable for acting as a host to encapsulate specific guest molecules, thereby achieving supramolecular cross-linking assembly. In order to introduce luminescence center into supramolecular assembly, a aliphatic nitrile-modified pyridine-2,6-dicarboxylic acid molecule was designed and synthesized for the first time. Its β-dicarboxylic acid structure serves as a coordination site for binding Terbium ions, while the aliphatic nitrile structure acts as a host-guest interaction site for complexing with the bridged bis-pillar[5]arene. Firstly, it underwent coordination reaction with Terbium ions to form a aliphatic nitrile-modified terbium ion complex. Subsequently, the host-guest interaction between bridged bis-pillar[5]arene and aliphatic nitrile-modified terbium ion complex was performed to form a lanthanide luminescent supramolecular polymer through cross-linking assembly in solution. The study revealed the fluorescence properties, aggregation morphologies of supramolecular polymer and described its formation process. Furthermore, fluorescence properties of the supramolecular polymer were utilized to investigate its stimulus-responsive behaviors toward a series of metal ions. It was found that the addition of copper ions could affect the luminescent capability of the supramolecular polymer, thus leading to a significant reduction of the system's fluorescence intensity. Based on it, fluorescent film was prepared by loading this supramolecular polymer onto hydrophobic substrates. Experimental results demonstrated that the film enable both qualitative detection and quantitative analysis of trace copper ions in water. making it an environmentally friendly, safe, sensitive, and convenient fluorescent probe for copper ions.

Key words: supramolecular polymer, pillar[5]arene, lanthanide luminescence, fluorescent probe, copper ion