A ‘Turn-on’ fluorogenic probe for selective and specific detection of Hg(II) ions

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Chemistry., 2025-02, Vol.459, p.116028, Article 116028
• Main Authors: Sultana, Tuhina, Mahato, Manas, Ahamed, Sabbir, Tohora, Najmin, Chourasia, Jyoti, Ghanta, Susanta, Kumar Das, Sudhir
• Format: Article
• Language: English
• Subjects: ESIPT; ICT; Mercury ions; Paper-strips; Sensors
• ISSN: 1010-6030
• DOI: 10.1016/j.jphotochem.2024.116028

[Display omitted] •An effective ‘turn on’ fluorogenic probe, BPMC has been introduced for selective and specific detection of Hg2+ ions.•The detection and quantification limits are determined to be in the µM range.•ICT and ESIPT processes are inhibited involved in BPMC in the presence of Hg2+ ions causing photoluminescence enhancement.•An BPMC-stained paper-strips-based test kit has been fabricated for on-spot detection.•The detection mechanism has been revealed through FT-IR, 1H NMR, and high-resolution mass spectrometric analysis. Mercury (Hg2+) and its associated compounds have drawn serious concern from the scientific communities for their extreme toxicity to human beings. The present article introduced a chromone-benzoxazole embracing an effective fluorogenic probe, (E)-3-(((4-(benzo[d]oxazol-2-yl) phenyl) imino) methyl)-2-methoxy-2H-chromen-4-ol (BPMC) for selective and specific detection of Hg2+ ions having detection and quantification limit in the µM range. A significant photoluminescence enhancement has been observed from BPMC solution (water-DMSO mixture, 50 % v/v) displaying low to highly intense blue-violet photoluminescence under a 365 nm UV lamp due to the inhibition of intramolecular charge transfer (ICT) and excited state intramolecular proton transfer (ESIPT) processes involved in BPMC. Furthermore, to achieve on-site detection of Hg2+ ions and investigate the practical utility of our developed probe, we have fabricated a BPMC-stained paper-strips-based test kit and demonstrated its practical effectiveness for on-spot detection. The details of the detection mechanism have been revealed through 1H NMR, FT-IR, and high-resolution mass spectrometric analysis. The present report evokes a broader perspective for tailoring ICT and ESIPT-based chromo-fluorogenic probes to accelerate their real-world application and environmental monitoring.