An Ultrastable Europium(III)–Organic Framework with the Capacity of Discriminating Fe²⁺/Fe³⁺ Ions in Various Solutions

An ultrastable luminescent europium–organic framework, {[Eu­(L)­(H₂O)₂]·NMP·H₂O}_<i>n</i> (<b>CTGU-2</b>; NMP = <i>N</i>-methyl-2-pyrrolidone), can first detect Fe²⁺/Fe³⁺ cations in different medium systems with high selectivity and sensitivity, and it also exhibits high sensitivity for Cr₂O₇^2– anion and acetone with a wide linear range and a low detection limit