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 (Y 3+ , Yb 3+ , Sc 3+ and Ce 3+ ) 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 Y 3+ with a fluorescence color change from red to yellow-green, while it exhibited fluorescence quenching for Yb 3+ . Additionally, it exhibited a selective sensing ability for Sc 3+ in MeCN solution with a fluorescence color change from red to yellow, and a fluorescence quenching effect for Ce 3+ . 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 (Y 3+ and Yb 3+ ) and MeCN (Sc 3+ and Ce 3+ ), respectively. The ICT effect of the TPE-A probe on Y 3+ was investigated using femtosecond transient absorption spectroscopy and quantum chemical calculations. The detection limits of Y 3+ , Yb 3+ , Sc 3+ and Ce 3+ 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-Sc 3+ hybrid system. This implies an efficient and simple method for the simultaneous analysis of trace rare earth metal elements (Y 3+ , Yb 3+ , Sc 3+ and Ce 3+ ) in complex environments.