Selective Fluorescent Turn-Off Detection of Picric Acid Using a Novel Tripodal Supramolecular Triazole-Trindane-Based Receptor

Applying click chemistry, a new C-3v-symmetric tripodal supramolecular receptor L based on para-nitrophenyl triazole trindane platform was introduced for the fluorescent turn-off sensing of picric acid (PA). The selectivity of the receptor L was examined towards various nitroaromatic compounds, such as picric acid, 4-nitrotoluene, 1-chloro-4-nitrobenzene, m-dinitrobenzene, 3-nitrotoluene, 2-nitrotoluene, nitrobenzene, p-nitrophenol and 1-chloro-2-nitrobenzene in aqueous DMSO medium. With micromolar detection limit, the receptor L showed selective fluorescence quenching at 421 nm in the presence of PA due to the energy transfer occurred from the receptor L to PA. The interaction between the receptor L and PA was complemented with the quantum mechanical calculations. Finally, the practical utility of L was validated by monitoring PA concentration in various real environmental water samples.