Highly selective colorimetric and fluorescent probe for F− and P2O74− based on AIEE and dual ESIPT

In this study, the Schiff base (probe 1) was designed and synthesized, using the moieties of benzothiazole and salicylaldehyde as signaling units. UV-visible and emission spectroscopy has been identified to study interaction of probe 1 with various anions. Absorption bands at 290 and 360 nm for probe 1 (20 µM; CH3CN) were observed and two fluorescence peaks at 415 and 540 nm obtained with excitation at 360 nm in CH3CN. Probe 1 (20 µM) developed a yellow color in presence of F− and P2O74− ions in their tetrabutylammonium salts. For both the ions, the corresponding absorption measurements revealed bathochromic shift of 85 nm. When complexed with anions, emission changes show that probe 1 acts as a "turn-on" sensor. Probe 1 shows detection limit (LOD) of 35.4 and 15.4 nM for F− and P2O74−, respectively. 1H NMR titration analyses revealed more about their mode of binding with probe 1.