Excited state double proton transfer efficient probe: Theoretical investigation and sensing ability towards Pb2+ and Al3+ ions

Abstract

Dual ESIPT efficient Schiff-base probe possessing multiple binding sites was synthesized which is capable of showing Aggregation Induced Emission (AIE) properties. Probe 1 behaves as a fluorescence “turn-on” chemosensor, showing interactions with Pb2+ and Al3+ ions in H2O-CH3CN solvent at pH≈7. The binding constant and detection limit for all the ions were calculated. The binding properties of probe 1 with all the ions were checked by Job's plot and the 1H NMR titration method. Further, the presence of dual intramolecular hydrogen bonding was confirmed theoretically by geometrical parameters and FTIR analysis. The potential energy curves (PECs) calculations for proton transfer coordinates verified that probe 1 shows a single ESIPT process. Thus with good selectivity and sensitivity and fast response time, a highly efficient platform for simultaneous detection of Pb2+ ions was generated using a simple molecule.