Naphthalene-derived Al3+-selective fluorescent chemosensor based on PET and ESIPT in aqueous solution

A simple fluorescent chemosensor HL based on naphthalene with high selectivity and sensitivity towards Al3+ over other commonly coexisting metal cations in fully aqueous solution to enhance the potential applications of the fluorescent chemosensor was developed. HL exhibited a significant fluorescence enhancement at 475 nm in the presence of Al3+ over other competitive metal ions with a low detection limit of 0.43 mu M due to the inhibition of the photo induced electron transfer (PET) and the excited-state intramolecular proton transfer (ESIPT). The 1:1 binding stoichiometry between HL and Al3+ was corroborated by the Job plot and the ESI-MS spectrum. Importantly, the reversible recognition process of HL to Al3+ will make HL could be used circularly and repeatedly in practical applications by addition of Na(2)EDTA. In addition, the binding behavior and sensing mechanism of HL to Al3+ were illustrated in detail by the H-1 NMR titration experiment. (C) 2017 Elsevier Ltd. All rights reserved.