A novel dinaphthodiaza-crown macrocycle-based luminescent chemosensor for selective and sensitive dual detection of CHCl3 and CCl4 in water

This study presents the design, synthesis, and characterization of a novel luminescent chemosensor based on a dinaphthodiaza-crown macrocycle (L) for the selective and sensitive dual detection of CHCl₃ and CCl₄ in water. L operates by monitoring fluorescence (FL) intensity changes at two distinct excitation wavelengths (293 and 370 nm), enabling simultaneous detection of CHCl₃ (via FL enhancement) and CCl₄ (via FL quenching). The detection limits for CHCl₃ and CCl₄ were calculated as 2.25 and 6.35 ppm, respectively, demonstrating high sensitivity compared to several conventional methods. Theoretical studies (DFT and TD-DFT) confirmed the interaction mechanisms, wherein CCl₄ interacts with the naphthalene moiety via C−Cl···π interactions to form a ground-state complex, leading to the observed static FL quenching, and CHCl₃ interaction with the carboxylate group via C−H···O hydrogen bonding, resulted in a 70 % increase in the FL intensity. Key advantages of this chemosensor include chemical stability, recyclability (with 90 % recovery after 4 cycles), and performance in aqueous environments, making it a promising tool for monitoring the chlorinated pollutants in water resources.