Synthesis and Fluoride Detection Properties of a Coumarin Derivative

A new and simple colorimetric receptor 1 was prepared easily by one-step condensation of 3-acetyl-4-hydroxycoumarin and 8-aminoquinoline. Its absorbance at λ 296 nm significantly increased upon addition of Fe 3+ with a turn-on mode. Furthermore, turn-off sensing happened when F – was added to the 1 –Fe 3+ complex formed in situ. The 1 –Fe 3+ complex showed high selectivity and low detection limit toward F – ion. Free Schiff base 1 was then given off for recognition Fe 3+ again. The reversible “off-on-off” sensing occurred upon sequential addition of Fe 3+ and F – .