A fluorescent probe with “AIE + ESIPT” characteristics for Cu2+ and F− ions estimation

We report a fluorescent probe 2 possessing hydroxyaryl Schiff's base onto tetraphenylethylene (TPE) moiety with characteristic of both aggregation induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT). The coupled AIE and ESIPT shows the significant advantages, such as no self quenching at high concentration, large stokes shift, high selectivity towards analyte etc. It has also been used for estimation of F− and Cu2+ ions amongst various anions and metal ions, respectively. Probe 2 shows the emission at 540 nm with a large stokes shift of 170 nm and presence of Cu2+ ions induce the restriction of intramolecular motions leading to high emission in the aggregated state (AIE) at longer wavelength (NIR region).