LAUSR

Abstract In this study, new hydrazide-imine conjugates (1–3) containing polyaromatic groups (pyrene, anthracene or phenanthrene) were prepared and used as fluorescent probes for the sensing of nitro-aromatic compounds. The compounds were structurally characterized by single crystal X-ray diffraction studies. X-ray analysis showed that the polyaromatic moieties of the compounds play an important role for the crystal packing of the structure. The compounds exhibit aggregation induced emissions (AIE) due to π-π stacking of poly aromatic groups of the compounds. This, in turn, effects the color coordinates (CIE) of the compounds. The fluorimetric sensing of nitrobenzene (NB), 4-nitrophenol (NP), 2,4-dinitrophenol (DNP) and 2,4,6-trinitrophenol (TNP) were studied by photoluminescence spectroscopy. Fluorimetric titrations showed that the nitro-aromatic compounds showed a quenching effect in the emission band of the probes due to the photoinduced electron transfer (PET) or fluorescence resonance energy transfer (FRET). The compounds showed better sensitivity towards nitrobenzene (NB) with low LOD values. Quenching constants for NB detections are 2.20 × 105 for (1), 5.49 × 105 for (2) and 7.86 × 105 for (3), respectively.