A coumarin-based fluorescent and colorimetric chemosensor for rapid detection of fluoride ion

Abstract A novel coumarin-based compound 1 featuring thiosemicarbazone as binding unit, was reported as a colorimetric and fluorescent probe for the detection of fluoride anion. The addition of F − to a solution of probe 1 in tetrahydrofuran resulted in evident naked-eye color change from green-yellow to orange-red under daylight and obvious fluorescence quenching within 3 s. And the detection limit toward F − was calculated to be as low as 2.16 × 10 −7  mol/L. 1 H NMR titrations proved that the interaction between 1 and fluoride ion: hydrogen bond at low fluoride ion concentration, deprotonation at high fluoride ion concentration. Besides, it exhibited highly sensitivity and selectivity for F − over other examined ions (Cl − , Br − , I − , AcO − , NO 3 − , HSO 4 − , H 2 PO 4 − ) in tetrahydrofuran solution.