A Benzodithiophene-Based Fluorescence Probe for Rapid Detection of Fluoride Ion.

A novel and simple fluorescence probe was synthesized from benzo[1,2- b:4,5- b′]dithiophene (BDT) and trimethylsilylethyne via Sonogashira reaction, and showed highly selective and sensitive fluorescence decreasing response towards F⁻. The probe molecule turned to a weakly fluorescent terminal alkyne moiety because its trimethylsilyl (TMS) group was cleaved by fluoride, which was proved by ¹H NMR titration. Whereas no distinct fluorescent changes were observed with the addition of other anions, such as Cl⁻, Br⁻, I⁻, AcO⁻ and H₂PO₄⁻. Upon the addition of F⁻, the maximum fluorescence emission wavelength shifted from 460 nm to 450 nm with a decrease of fluorescence intensity by 40% within 20 s. Moreover, the detection limit towards F⁻ was calculated to be as low as 73.5 nmol/L. [ABSTRACT FROM AUTHOR]