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Coumarin based colorimetric and fluorescence on-off chemosensor for F-, CN- and Cu2+ ions
Debashis Roy1, Arijit Chakraborty2, Rina Ghosh1
1Department of Chemistry, Jadavpur University, Kolkata 700032, India.
Abstract:
(E)-4-Chloro-3-[{2-(4-nitrophenyl)hydrazono}methyl]-2H-chromen-2-one (C), a coumarin derivative has been studied toward its ion sensing properties for F-, CN- and Cu2+. A proton-transfer mechanism for F- sensing has been deduced with the help of 1H NMR titration alongwith from the changes in the absorption and emission spectra of C in the presence of F-. C formed 1:1 stoichiometric complex with each of these analytes. Sensing of C toward Cu2+ is poor, but interestingly in the presence of F-or CN- the sensing ability of Cu2+ gets enhanced many folds, and C can act as F-or CN- mediated off-on sensor for Cu2+. Moreover, colorimetric strip (pre-coated with the coumarin derived compound) tests for F-and CN- from their DMSO solution at high temperature (~100°C) opens up the door for easiest naked eye recognition and distinction of these ions, and also for naked-eye detection of F- and CN- from its aqueous solution at high temperature (~100°C).
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