Fluorescence 'turn-on' sensor for F- derived from vitamin B-6 cofactor

A novel vitamin B-6 Schiff base analog (L) was synthesized by combining vitamin B-6 cofactor pyridoxal with 2-aminophenol. Receptor L displays a color change detectable by the naked-eye from yellow to red in the presence of fluoride and acetate due to the formation of hydrogen bonding host-guest complexes in 1 : 1 stoichiometry. Importantly, receptor L showed fluoride-selective ` turnon' fluorescent response with a detection limit (3 sigma) of 7.39 x 10(-8) M.