Thiophene and diethylaminophenol-based “turn-on” fluorescence chemosensor for detection of Al3+ and F- in a near-perfect aqueous solution

Abstract

A new fluorescent sensor 1, based on thiophene and diethylaminophenol moieties, has been synthesized and its binding capabilities for metal-ion and anion recognition were investigated. The sensor I showed turn-on' fluorescence in the presence of Al3+ and F-. The sensing behaviors of 1 with Al3+ and F- were studied by using photophysical experiments, H-1 NMR titration, and ESI-mass spectrometry analysis. The detection limits for the analysis of Al3+ and F- were found to be 0.41 mu M and 1436 mu M, respectively, which are below the WHO guidelines for drinking water (7.41 mu M for Al3+ and 79 mu M for F-). Moreover, turn-on fluorescence of 1 toward Al3+ and F- caused by intramolecular charge transfer (ICT) was well explained by density functional theory (DFT) calculations. Importantly, 1 could be used to detect Al3+ in the living cells.