Furan and Julolidine-Based "Turn-on" Fluorescence Chemosensor for Detection of F in a Near-Perfect Aqueous Solution.

A new fluorescent sensor 1, containing furan and julolidine moieties linked through a Schiff-base, has been synthesized. Distinct "turn-on" fluorescence enhancement of 1 was observed upon the addition of F in a near-perfect aqueous solution. The binding capabilities of 1 with F were studied by using fluorescent spectroscopic techniques, ESI-mass analysis and NMR titration measurements. The detection limit for the analysis of F was found to be 10.02 μM, which is below the WHO guideline (79 μM) for drinking water. Practically, the sensing ability of 1 for F was successfully applied in real water samples. The sensing mechanism for F was proposed to be the ICT mechanism via the hydrogen bonding, which was well explained by theoretical calculations.