A simple ratiometric and colorimetric chemosensor for the selective detection of fluoride in DMSO buffered solution.

A derivative of squaramide (cyclobuta[b]quinoxaline-1, 2(3H, 8H)-dione) has been synthesized for the ratiometric and colorimetric sensing of F − in aqueous solution in competitive fashion. With F − , probe 1 showed a highly selective naked-eye detectable color change along with a characteristic UV–Vis absorbance over other tested ions, which probably originates from the deprotonation occurred between 1 and F − , as proved by the 1 H NMR titration experiments and DFT calculations. [ABSTRACT FROM AUTHOR]