An NIR-emissive AIEgen with dual sensing ability: An azine-based chemodosimeter for discriminative ppb-level detection of hydrazine and bisulfite ions

A new near-infrared (NIR) emissive aggregation-induced emission (AIE) active unsymmetrical azine (benzophenone-azine-phenyl-cyanovinyl-pyridinium chloride, BAPCP) with dual sensing ability is developed for discriminative detection of hydrazine (N2H4) and bisulfite (HSO3−) ions. The azine-based chemodosimeter, BAPCP was synthesized in a sustainable way adopting a solvent-free one-pot tandem mechanochemical route. The probe is nonfluorescent in organic solutions and displayed strong AIE at higher water fractions (upto 99% of H2O) with an emission maximum at 718 nm and a large Stokes shift of 333 nm. BAPCP could detect N2H4 by a ratiometric response at 525 nm by cleavage of the cyano-pyridinium ethylene group and showed a turn-off response against HSO3− by its nucleophilic addition across the olefinic bond of BAPCP. The probe showed excellent selectivity and low limit of detection (LOD) of 4 × 10−8 M (1.2 ppb) and 2.5 × 10−8 M (2 ppb) for N2H4 and HSO3−, respectively. The practical utility of the probe was demonstrated by solid-phase detection of these analytes on silica-coated TLC plates, followed by ImageJ analysis for on-site quantitation purposes. BAPCP is also capable of the detection of intracellular N2H4 and HSO3− in live cells.