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. 2025 Jun;35(6):4129-4142.
doi: 10.1007/s10895-024-03813-7. Epub 2024 Jul 2.

Nitroquinolone Fused Salicyl and Naphthyl Hydrazone Fluorescent Probes for the Detection of Fe3+and Pb2+ Ions

Vandana Nandakumar  1 , Sentamil Selvi Ramasamy  1 , Kaviyarasu Adhigaman  1 , Narmatha Ganesan  2 , Divyakaaviri Subramani  3 , Shankar Ramasamy  3 , Raju Nandhakumar  2 , Suresh Thangaraj  4
Affiliations

Nitroquinolone Fused Salicyl and Naphthyl Hydrazone Fluorescent Probes for the Detection of Fe3+and Pb2+ Ions

Vandana Nandakumar et al. J Fluoresc. 2025 Jun.

Abstract

The application of quinolones stretches over a large umbrella of medicinal field as well as chemosensor due to the presence of privileged heterocyclic aromatic rig system. Salicyl and Naphthyl Hydrazide motifs are also established fluorophore groups. Therefore in this work, we have designed and synthesized Salicyl hydrazide (3a-c) and naphthyl hydrazide fused nitroquinolones (5a-c) investigated for their fluorescent behaviour. Preliminary UV- absorption studies were carried out and the metal selectivity were examined with various metal ion. Among them, it was found that compound 3a was selective towards Fe3+ ions (λex = 330 nm, 1:1 DMF:H2O at pH = 7.4 in HEPES Buffer medium). 3a shows decrease emission intensity in presence of Fe3+ ions. Compound 5a shows enhancement in fluorescence intensity upon addition of Pb2+ ion (λex = 280 nm, 1:1 DMF:H2O at pH = 7.4 in HEPES Buffer medium). Further, the concentration dependence, competitive binding and EDTA reversibility were studied for selected compounds towards the respective cations selectivity. Jobs plot analysis indicate that 1:1 binding of 3a with Fe3+ ion (Ka = 3.17 x104M-1 and Limit Of Detection (LOD) = 5.1 × 10-7 M) whereas 5a showed 1:2 binding mode with Pb2+ ions (Ka = 2.14 × 106 M-1 and Limit Of Detection (LOD) = 2.613 × 10-9 M). Density Function Theoretical studies were performed as support for the experimental results.

Keywords: Chemosensors; DFT; Fluorescence; Hydrazones; Iron; Lead; PET.

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Conflict of interest statement

Declarations. Ethics Approval: Authors declare that there was no necessity for ethics approval regarding the current study. Conflict of Interest: The authors declare that there are no competing interests in financial or personal relationships that have appeared to influence the work related to this paper.

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