New fluorescent chemosensor based on exciplex signaling mechanism.

[reaction: see text]. A novel fluorescent chemosensor (compound 1) containing aminonaphthol, which selectively recognizes fluoride anion with high sensitivity, was synthesized. The fluorescence of compound 1 was quenched rapidly by fluoride ion, and a new peak at a longer wavelength emerged concurrently, which constituted the signature for fluoride detection. The mechanism of exciplex formation was proposed for the interesting observation.