Highly sensitive colorimetric and fluorescence “Turn On” sensing of hydrazine via restriction in intramolecular vibrations of AIEE active fluorophore

Hydrazine (N₂H₄), a B2 toxin, harms the environment due to its extensive use in industries. Because of its lethal hypertoxicity and carcinogenicity, there is a crucial need to identify and quantify hydrazine. For this purpose, we developed a colorimetric and fluorometric probe MFB for sensitive and selective detection of hydrazine (N₂H₄). The mefenamic acid-derived benzamide MFB was easily synthesized by coupling reagent through a single step. Fluorescent probe MFB shows the extraordinary aggregation-induced emission enhancement (AIEE) characteristics with the formation of aggregates. The DLS analysis was performed to determine the aggregates particle size and interaction with probe MFB. The probe MFB exhibits a strong emission wavelength at 444 nm in aggregated state. Furthermore, the probe MFB has selectively detected the hydrazine (N₂H₄) through a blockage of semi-photoinduced electron transfer and restricted intramolecular vibrations mechanism with the lowest possible detectable amount of 47.3 nM. The interaction of MFB with hydrazine (N₂H₄) was verified by the UV–Visible and ¹H NMR titration experiments. Moreover, theoretical studies like orbitals energy calculation and type of interactions were executed to support the experimental findings. Interestingly, the probe MFB was employed in both solution and solid states for the favourable detection of hydrazine (N₂H₄) in real-time analysis including drinkable water, beverages, industrial wastewater, soil samples, mung bean sprouts and artificial urine samples.