A luminescent lanthanide complex-based anion sensor with electron-donating methoxy groups for monitoring multiple anions in environmental and biological processes

We designed a ternary europium (III) tris(2-thenoyltrifluoroacetonate) with 2-(3,4,5-trimethoxyphenyl)imidazo[4,5-f]-1,10-phenanthroline (1) ligands for the luminescent detection of various anions, such as fluoride, acetate and dihydrogen phosphate. Characterization of the sensor’s photophysical properties and via NMR showed that the sensor exhibits striking emission changes to fluoride (purple), acetate (green) and dihydrogen phosphate (blue) anions, respectively. Its fluorescence lifetime was determined to be 1.10 ms for europium ions and the complex showed an overall quantum yield of 10% in DMSO.Furthermore, transparent hybrid thick films composed of the europium complex and poly-methyl methacrylate matrix were successfully prepared via copolymerization. The resulting film overall displayed intense red emissions associated with europium ions. Fluorescence microscopic evaluation showed a homogenous distribution of aggregates with average diameters of 30–50 μm throughout the film. The accordingly produced film could give rise to a luminescence change to purple in response to fluoride anions.

A ternary europium (III) tris(2-thenoyltrifluoroacetonate) with 2-(3,4,5-trimethoxy phenyl)imidazo[4,5-f]-1,10-phenanthroline (1) was prepared and it can detect various anions such as F−, AcO− and H2PO4-. Spectroscopic studies of UV–vis, Fluorescence and NMR present that the sensor exhibits striking emission changes to fluoride (purple), acetate anions (green) and H2PO4- (blue), respectively. More importantly, transparent hybrid thick films (poly-methyl methacrylate) show intense red emissions and give rise to luminescence change in fluoride anion containing DMSO solution.Figure optionsDownload as PowerPoint slideHighlights
► Ternary complex was strong red emissive.
► The sensor exhibits striking emission changes to anions.
► Luminescent could display luminescence change for fluoride anion.