Design, synthesis, and spectrofluorimetric analysis of a novel fluorene-based chemosensor for the selective detection of picric acid

Abstract

Fluorene-based probes are efficient candidates for sensing nitroaromatics and toxins. A novel fluorophore based on fluorene and terephthalaldehyde 1,4-YBF (1,4-ylidene-bis-fluorene) has been designed and synthesized for the efficient sensing of 2,4,6-trinitrophenol (picric acid) in solution. X-ray crystallographic studies, NMR, and mass analyses revealed the molecular stacking and exact structure of 1,4-YBF, which was further structurally optimised using the DFT technique. The optical properties of the newly synthesized compound were studied using UV–Vis and spectrofluorimetric analyses. The fluorophore was subjected to detailed sensing studies of various nitroaromatics, among which it was identified that picric acid (PA) exhibited the maximum quenching efficiency. The excellent sensing ability of the fluorophore was probably attributed to the photoinduced electron transfer (PET) mechanism. Further, pH studies and interference studies, along with its high selectivity towards PA and an LOD of 0.314 µM, revealed 1,4-YBF to be efficient in the detection of picric acid at a micromolar level.