Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan 250100, China.
Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico 87131, United States.
Langmuir. 2020 Mar 24;36(11):2911-2919. doi: 10.1021/acs.langmuir.0c00007. Epub 2020 Mar 12.
Novel luminescent vesicles with enhanced emission were successfully achieved for the first time by an amphiphilic europium complex through its spontaneously self-assembly in an ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim]PF). The complex was prepared by europium ions coordinated with terpyridine ligands, which were modified with the hydrophilic ethoxy chains. The enhanced absolute quantum yield and prolonged fluorescence lifetime of complex in vesicles were observed because of the effective shielding of the quench effects caused by both solvent and complex concentration. Compared to the aggregates formed in other solvents, the vesicles obtained in [Bmim]PF showed the best luminescence intensity with the quantum efficiency (37.74%) and luminescent emission lifetime (1.915 ms) both increased about 10 times more. Furthermore, this europium complex was designed to show unsaturated coordination, which made the vesicle luminescence easily quenched when contacting with water. The fluorescence sensing of water with this vesicle as probe was therefore possible, where several unique properties like high sensitivity, low detection limit (0.05 vol %), visible color change, and fast response had been observed. Such designed systems are expected to provide strategies to develop novel supramolecular aggregates in ionic liquids and offer guidance for luminescence detection with facile and wide applications.
首次通过两亲性铕配合物在离子液体 1-丁基-3-甲基咪唑六氟磷酸盐([Bmim]PF)中的自组装成功制备了具有增强发射的新型发光囊泡。该配合物由与具有亲水性乙氧基链的三吡啶配体配位的铕离子制备。由于溶剂和配合物浓度引起的猝灭效应的有效屏蔽，观察到囊泡中配合物的绝对量子产率和荧光寿命延长。与在其他溶剂中形成的聚集体相比，在 [Bmim]PF 中获得的囊泡表现出最佳的发光强度，量子效率（37.74%）和发光发射寿命（1.915 ms）均增加了约 10 倍。此外，该铕配合物被设计为显示不饱和配位，这使得囊泡发光在与水接触时容易猝灭。因此，可以使用这种囊泡作为探针进行水的荧光传感，观察到了高灵敏度、低检测限（0.05 体积%）、可见颜色变化和快速响应等独特性质。预计此类设计的系统将为在离子液体中开发新型超分子聚集体提供策略，并为具有简便和广泛应用的荧光检测提供指导。
