DESIGN AND SYNTHESIS OF SIMPLE QUINOLINE-BASED ORGANIC MOLECULES AS DUAL/MULTIFUNCTIONAL CHEMOSENSORS FOR THE DETECTION OF CU2+/FE3+ IONS

Abstract

The current research deals with the sensitivity of a turn-on-off fluorescence chemosensor using the probe, namely (E)-2-(((2‑hydroxy-5-methylphenyl) imino)methyl) quinolin-8-ol (HQ-AMP) as a selective detection of Cu2+/Fe3+ ions in DMSO: H2O (1:1, v/v). The probe HQ-AMP was synthesized using a simple acid catalyst, Schiff base condensation, which involves the reaction between aldehyde and amine. This probe shows a significant fluorescence response towards Cu2+ and Fe3+ ions among the other alkaline earth metal ions. The HQ-AMP forms a 1:1 stoichiometry complex with a high binding constant for Cu2+ and Fe3+ ions with a low detection limit of 34 nM and 47 nM, respectively. Due to their strong intermolecular charge transfer properties, the probe HQ-AMP shows intense fluorescence at 488 nm upon excitation at 350 nm. The selective fluorescence quenching of probe HQ-AMP with Cu2+/Fe3+ ions shows static/dynamic quenching and their quenching constant of 1.93 × 10−8 and 2.06 × 10−8, respectively. Also, the probe shows the highest selectivity towards Cu2+/Fe3+ ions over the other tested metal ions.