Colorimetric and state responsive F- organogel chemosensor with reversible status recovery via H2O

• Three gelators G1, G2 and G3 based on pyridine and coumarin were designed and synthesized. • G1 -DMF gel could act as chemosensor for F - accompanied by obvious colorimetric and state changes. • G1 -DMF-F - sol could restore to the original gel state within seconds by adding trace amounts of H 2 O. Three organogelators G1, G2 and G3 based on pyridine and coumarin were designed and synthesized. G1 showed superior gelling performance compared with G2 and G3 and it could form stable organogels with the vast majority of organic solvents, it indicated that the position of the nitrogen atom in pyridine moieties remarkably affected the gelation properties. UV–Vis spectra, FT-IR spectra and concentration dependent 1 H NMR experiments revealed that gel formation was primarily driven by synergistic hydrogen bonding and π-π stacking interactions among G1 molecules. The stable G1 -DMF gel underwent rapid transformation from light pink gel to tangerine sol upon F - addition. Remarkably, the G1 -DMF-F - sol could restore to the original gel state within seconds by adding trace amounts of H 2 O.