Discriminative ‘Turn-on’ Detection of Al³⁺ and Ga³⁺ Ions as Well as Aspartic Acid by Two Fluorescent Chemosensors

Abstract

In this work, two Schiff-base-based chemosensors L1 and L2 containing electron-rich quinoline and anthracene rings were designed. L1 is AIEE active in a MeOH-H2O solvent system while formed aggregates as confirmed by the DLS measurements and fluorescence lifetime studies. The chemosensor L1 was used for the sensitive, selective, and reversible ‘turn-on’ detection of Al3+ and Ga3+ ions as well as Aspartic Acid (Asp). Chemosensor L2, an isomer of L1, was able to selectively detect Ga3+ ion even in the presence of Al3+ ions and thus was able to discriminate between the two ions. The binding mode of chemosensors with analytes was substantiated through a combination of 1H NMR spectra, mass spectra, and DFT studies. The ‘turn-on’ nature of fluorescence sensing by the two chemosensors enabled the development of colorimetric detection, filter-paper-based test strips, and polystyrene film-based detection techniques.

Keywords

• Schiff base
• sensing
• aluminum
• AIEE
• aspartic acid