TPE-Fluorogens Showing AIEE Phenomenon for Sensing of Al3+ Ions

Abstract

Tetraphenylethylene based Schiff bases 4 and 5 have been synthesized. Probes 4 and 5 exhibit highly selective absorption and emission behavior towards Al3+ ions. Probes display unique AIEE (Aggregation Induced Emission Enhancement) phenomenon in combination of Excited State Intramolecular Proton Transfer (ESIPT) and ion-induced aggregation. The probes in the the presence of Al3+ ions showed visible color change from yellow to colorless under visible light and lighten-up emission under UV-light. The probes 4 and 5 showed the lowest detection limit of 0.47 µM and 0.3 µM respectively. The probe 4 upon aggregation showed morphological change from amorphous spheres to crystalline needles whereas probe 5 showed morphological change from spheres to agglomerated clusters.