High-performance fluorescence sensing of lanthanum ions (La3+) by a polydentate pyridyl-based quinoxaline derivative

A polydentate pyridyl ligand, 2,3,6,7,10,11-hexa(2-pyridyl)-dipyrazino[2,3-f:2′,3′-h] quinoxaline (HPDQ), was found to have excellent light-emitting selectivity to La³⁺ over many other lanthanide metal ions (Ce³⁺, Pr³⁺, Nd³⁺, Sm³⁺, Eu³⁺, Gd³⁺, Tb³⁺, Dy³⁺, Ho³⁺, Er³⁺, Tm³⁺, Yb³⁺, and Lu³⁺).