A dual-model and on–off fluorescent Al3+/Cu2+-chemosensor and the detection of F−/Al3+ with ‘in situ’ prepared Al3+/Cu2+ complexes

Abstract

A multifunctional fluorescent chemosensor for Al³⁺ and Cu²⁺ has been developed, which displays a dual-model and on–off fluorescence response upon addition of Al³⁺ and Cu²⁺ respectively. The fluorescence signals of the chemosensor can be restored with F⁻ and ethylenediaminetetraacetic acid (EDTA) disodium for Al³⁺ and Cu²⁺, showing that the binding of the chemosensor and Al³⁺/Cu²⁺ is chemically reversible. The ‘in situ’ prepared Al³⁺ complex (1·Al) showed high selectivity toward F⁻, which can be applied to distinguish F⁻ from Cl⁻, Br⁻ and I⁻. Moreover, the fluorescence emission intensity of the ‘in situ’ prepared Cu²⁺ complex (1·Cu) is increased with the addition of Al³⁺, demonstrating that 1·Cu could be a good off–on Al³⁺ sensor candidate.