Synthesis, Characterization, Theoretical Analysis, and Solvatochromic Evaluation of Aminoquinoline-Based AIEE-Active Schiff Base, along with its Application as a Probe for Hg2+ and Fe2+ Detection.

Introducing the new Quinoline-based Schiff base (BB-SB), crafted through a single-step condensation reaction between 5-aminoquinoline and 5-bromo-2-thiophene carboxaldehyde and meticulously characterized using a range of spectroscopic techniques. This synthesized compound showcases exceptional aggregation-induced enhanced emission (AIEE) properties, boasting a staggering 38-fold boost in fluorescence intensity and a 24 nm redshift when tested in a 50:50 acetonitrile-water blend, compared to pure DMF. The impressive AIEE performance was further validated by dynamic light scattering (DLS) analysis. BB-SB displays its ability to selectively identify Fe2+ and Hg2+ ions amidst a sea of 16 heavy metals, employing spectrofluorometric techniques with remarkable sensitivity. The limits of detection (LOD) for Fe2+ and Hg2+ stand at 3.3 μM and 1.3 μM, respectively. Job's plot analysis revealed a 1:2 ligand-to-metal binding stoichiometry for both ions. The quenching mechanism for mercury was delved into through Stern-Volmer plots, and was found to follow static quenching mechanism. Moreover, the aldehyde intermediate generated during the synthesis of BB-SB displayed intriguing solvatochromic behaviour, featuring donor and acceptor moieties. This feature highlights its potential as a candidate for color-tunable, solution-processable optoelectronic devices. While the present work focuses on sensing performance, the preliminary findings suggest that future exploration of the optoelectronic applications of these systems, including OLEDs, may be promising.