First fluorescence sensor for simultaneous detecting four rare earth metal elements (Y3+, Yb3+, Sc3+ and Ce3+).

This paper reports the first fluorescent sensor that can simultaneously detect multiple rare earth metal ions (Y3+, Yb3+, Sc3+ and Ce3+) in a variety of rare earth metal ions. The Schiff base TPE-A was synthesized in 85% yield by the condensation reaction of formyltetrastyrene with 4-aminoantipyrine. Long wavelength fluorescence of TPE-A was observed at 500-650 nm in both MeOH and MeCN solutions. In methanol, it showed a highly selective response to Y3+ with a fluorescence color change from red to yellow-green, while it exhibited fluorescence quenching for Yb3+. Additionally, it exhibited a selective sensing ability for Sc3+ in MeCN solution with a fluorescence color change from red to yellow, and a fluorescence quenching effect for Ce3+. In addition, it can detect these four rare earth metal ions simultaneously by fluorescence changes with the assistance of EDTA-2Na. It can be used as a fluorescence sensor for MeOH (Y3+ and Yb3+) and MeCN (Sc3+ and Ce3+), respectively. The ICT effect of the TPE-A probe on Y3+ was investigated using femtosecond transient absorption spectroscopy and quantum chemical calculations. The detection limits of Y3+, Yb3+, Sc3+ and Ce3+ were 1.6 × 10-8 mol/L, 1.04 × 10-7 mol/L, 8.35 × 10-8 mol/L and 1.31 × 10-8 mol/L, respectively, as deduced from Job's plots, spectral titrations, and ESI-MS. And the detection of measured water in MeCN was realized by TPE-A-Sc3+ hybrid system. This implies an efficient and simple method for the simultaneous analysis of trace rare earth metal elements (Y3+, Yb3+, Sc3+ and Ce3+) in complex environments.