Internal electric field driven chromofluorescent chemodosimeter for fluoride ions

Receptor 1 (50 μM, λmax 410 nm, ɛ 5760), bearing pyridinium unit conjugated to anthrapyridone moiety, opens double channel in absorbance at 490 nm (orange, ɛ 5760) between 5 μM and 75 μM of F− ions and at 630 nm (green, ɛ 24,000) between 75 μM and 600 μM of F− ions. Fluoride ions induced fluorescence enhancement (>25 times) in 1 at 510 nm enables selective estimation of 0.5–5 μm fluoride ions.