Propylimidazole Functionalized Coumarin Derivative as Dual Responsive Fluorescent Chemoprobe for Picric Acid and Fe3+ Recognition: DFT and Natural Spring Water Applications.

A propylimidazole functionalized coumarin derivative (IPC) was fabricated for the first time and applied as a dual responsive fluorescent chemoprobe for sensitive and selective recognition of picric acid (PA) and Fe3+. Strong fluorescence quenching phenomena of the IPC were observed in H2O/ACN (5/95, v/v) medium (λem=408 nm) upon the additions of Fe3+or PA. The fabricated dual responsive IPC offered good selectivity and sensitivity with the low limit of detection values (0.92 µM for PA and 0.22 µM for Fe3+) lower than the acceptable amounts of Fe3+ and PA by the international official authorities. The validation study for the chemoprobe IPC for PA and Fe3+ was also performed. The interaction phenomena of IPC with PA and Fe3+ based on the findings of a range of experiments were considered and DFT computations were done to verify their recognition mechanisms. The sensing phenomena of IPC towards PA (1:1) and Fe3+ (3:1) were confirmed by the MALDI TOF-MS, FT-IR, 1H-NMR titration and Job's methods. Furthermore, the compound IPC was effectively applied as a fluorescent sensor for Fe3+ and PA detection in real natural spring water samples.