Trefoil-Shaped Metal-Organic Cages as Fluorescent Chemosensors for Multiple Detection of Fe 3+ , Cr 2 O 7 2- , and Antibiotics.

The construction of metal-organic cages (MOCs) with specific structures and fluorescence sensing properties is of much importance and challenging. Herein, a novel phenanthroline-based metal-organic cage, [CdL·6MeOH·6HO] (), was synthesized by metal-directed assembly of the ligand 3,3'-[(1,1')-(1,10-phenanthroline-2,9-diyl)bis(ethene-2,1-diyl)]dibenzoic acid () and CdI using a solvothermal method. According to single-crystal X-ray analysis, cage exhibits a rare trefoil-shaped structure. Meanwhile, the discrete MOCs are further stacked into a 3D porous supramolecular structure through abundant intermolecular C-H···O interactions. Additionally, through exploration of fluorescence sensing on cations, anions, and antibiotics in aqueous solution, the experimental results indicate that cage has excellent fluorescence sensing abilities for Fe, CrO, and nitrofuran and nitroimidazole antibiotics. The sensing ability of remains unaltered for five cycles toward all analytes. The above results suggested that cage can be considered a potential multiple sensor for the detection of Fe, CrO, and some antibiotics.