A dual-functional AIE luminogen for sensitive nitro explosive detection and efficient photolabeling

Abstract

Luminescent materials with aggregation-induced emission (AIE) characteristics have gained considerable attention as highly effective optical sensing platforms due to their distinct photophysical properties. In this study, an anthracene Schiff base, AnTPh, has been synthesized via a facile one-step condensation reaction for selective detection of picric acid among various nitroaromatic compounds. Photoluminescence and UV-vis analyses confirmed the AIE feature of AnTPh in a CH₃CN–H₂O solvent system. Further characterization using time-resolved fluorescence (TRF) and scanning electron microscopy (SEM) reinforced its AIE behavior, revealing an associated increase in fluorescence lifetime. The aggregated AnTPh structures exhibited strong emission and demonstrated selective fluorescence quenching in response to picric acid when excited at 400 nm. With a high Stern–Volmer constant (7.3 × 10⁵ M⁻¹) and a detection limit of 0.65 μM, AnTPh displayed excellent sensitivity, highlighting its potential for nitroexplosive detection. Mechanistic investigations suggested a static quenching process facilitated by ground-state complex formation between AnTPh aggregates and picric acid. Beyond its sensing capabilities, AnTPh also exhibited notable antibacterial activity against E. coli and S. aureus, as confirmed through disc diffusion assays. Furthermore, its luminescent properties enabled effective microbial photolabeling, positioning AnTPh as a promising candidate for future biomedical applications.