A novel AIE chemosensor based on a coumarin functionalized pillar[5]arene for multi-analyte detection and application in logic gates

Abstract

Aggregation induced emission (AIE) active molecules are widely applied for multi-analyte detection due to their unique advantages over conventional fluorescent probes. Herein, a novel coumarin functionalized pillar[5]arene (PX) has been designed and synthesized. It has strong AIE activity, and the fluorescence quantum yield of PX turned out to be 35.0% in DMF/H₂O (7 : 3, v/v) binary solution (1.0 × 10⁻⁴ M). Meanwhile, the optimized structure of PX was obtained by theoretical calculation at the B3LYP/6-311G level. Interestingly, the PX displays high sensitivity to multiple analytes, such as Fe³⁺ and Ba²⁺. The limits of detection (LODs) of PX for Fe³⁺ and Ba²⁺ are 1.67 × 10⁻⁷ M and 5.89 × 10⁻⁸ M, respectively. In addition, by introducing metal ions into the AIE chemosensor of PX, a metal-coordinated chemosensor (PX–M) was obtained. The PX–Fe and PX–Ba show selective fluorescence “turn on” detection of H₂PO₄⁻ (LOD = 1.50 × 10⁻⁷ M) and CN⁻ (LOD = 6.20 × 10⁻⁷ M), respectively. The multi-analyte detection mechanism of PX was based on multiple competitions of “exo-wall π–π” interactions and cation–π interactions. Notably, we have prepared logic gates controlled by Fe³⁺/Ba²⁺ and H₂PO₄⁻/CN⁻ at the molecular level, which can quickly and efficiently detect ions in aqueous solutions. Moreover, we also prepared test films, and an Fe³⁺ test kit was prepared by loading PX on a silica gel plate. This study provides a new way for multi-analyte detection.