A New Fluorescent Sensor for Fe³⁺ Based on Glycoluril Molecular Clip

The application of fluorescent method to metal ions detection features high sensitivity, simple operation and real-time monitoring. A 2,7-dihydroxynaphthalene-functionalized dimethyl glycoluril (called clip 1) was synthesized, using a relatively simple method. And it is fully characterized by ¹H NMR, ¹³C NMR, HR-MS and single crystal X-ray diffraction. The recognition properties of molecular clip 1 were analyzed systematically toward several metal ions using fluorescence spectroscopy, and it was found that molecular clip 1 is selective and sensitive to Fe³⁺. At the same time, the clip 1 shows good anti-interference ability when other metal ions existed. The limit detection of Fe³⁺ is 3×10⁻⁷M. The fluorescence of clip 1 was quenched apparently by Fe³⁺, which was speculated to be caused by ligand–metal charge transfer mechanism (LMCT). As a new fluorescence probe for Fe³⁺ ion, it may expanded the application of glycoluril molecular clips.