Synthesis of a Cd-MOF Fluorescence Sensor and Its Detection of Fe 3+ , Fluazinam, TNP, and Sulfasalazine Enteric-Coated Tablets in Aqueous Solution.

A Cd-based metal-organic framework (Cd-MOF), named after {[Cd(ttc)(H 2 O)]·H 2 O} n (ttc = 1-imidazole-1-yl-2,4,6-benzene-tricarboxylic acid), was synthesized using the solvothermal reaction. The single-crystal structure was determined by single X-ray diffraction analysis, and crystalline characteristics and composition were confirmed by powder X-ray diffraction (PXRD) and thermogravimetric analysis (TG), respectively. Structural analysis showed that the Cd 2+ ion is in the seven-coordinated mode, in which ttc 2- ion adopts the μ 4 -η 1 -η 1 -η 2 -η 2 coordination mode. It is worth noting that the Cd 2+ ion is connected to ttc 2- to form a 2D network, and the adjacent 2D network is expanded into a 3D supramolecular network structure through weak hydrogen bonds. The fluorescence sensing experiments indicated that Cd-MOF could not only be used as a fluorescence sensor for Fe 3+ , fluazinam (FLU), and 2,4,6-trinitrophenolol (TNP) but also for sulfasalazine detection in aqueous solution. To verify the sensitivity of the fluorescent probe, we calculated its detection limit: 5.34 × 10 -8 M (Fe 3+ ), 7.8 × 10 -8 M (FLU), 1.21 × 10 -7 M (TNP), and 2.67 × 10 -7 M (SECT). In addition, the quenching mechanism was thoroughly studied.