A supramolecular self-assembly host–guest system from cyclodextrin as an absolute water-soluble fluorescence sensor for aluminium ions: synthesis, characterization and sensing activity

In the study, an organic molecule derived from paeonol and anthraniloyl hydrazine (L) was synthesized via a Schiff-base reaction. Moreover, a host–guest system composed of TEPA-β-CD and L was self-assembled via supramolecular interactions. The organic molecule and host–guest system were characterized via NMR, HRMS, IR, and SEM. In addition, the internal structure of the system was clearly observed via HRTEM. The host–guest system exhibited absolute water-solubility. Via the fluorescence behavior toward several metal ions in aqueous media without organic solvents (pH = 7.2), the host–guest system showed high selectivity toward Al3+ over other commonly coexistent metal ions. Therefore, this host–guest system can be used as a fluorescence sensor for aluminium ions in aqueous media. Moreover, a large binding constant (5.84 × 104 M−1) between the sensor and Al3+ was calculated via a fluorescent titration experiment. Additionally, the absolute water-solubility activity effectively enhanced the application value of the host–guest system for tracking and detection of Al3+.