Near-Infrared Colorimetric and Ratiometric Fluorescence Sensor for Fluoride Ions

摘要

Two novel benzothiadiazole derivatives were prepared. Clear color changes from orange-red to blue (DPCN) and pink to green (DPTPE) were observed after the addition of fluoride ions (F-). DPCN and DPTPE displayed ratiometric fluorescence changes in the presence of F-. H-1-NMR titration and DFT calculations confirmed deprotonation in the presence of F-. Compared with DPTPE, the hydrogen proton of the imine group in DPCN had higher activity due to the influence of the strong electron-withdrawing cyano group, such that it was more easily deprotonated and the detection limit for F- was much lower. This work provided guidance for the further design and preparation benzothiadiazole based colorimetric and ratiometric fluorescence sensor for F-.