Fabrication of Two Isomorphic and Hyperstable Rare Earth-Based Metal-Organic Frameworks with Efficient Ratiometric Probe and Photocatalytic Performances.

Two isomorphic lanthanide compounds {[Ln(ddpp)(HO)]·CHCN} (Ln = Eu and Gd, Hddpp = 2,5-di(2',4'-dicarboxylphenyl)pyridine) were synthesized. Complex displays ultrahigh acid-base stability and thermal stability. Furthermore, luminescence measurements revealed that could detect quinolone antibiotics with an ultralow limit of detection in aqueous solution. The ratiometric probe properties for sensing antibiotics could be attributed to the incompletely sensitized Eu ion of the ligand. Remarkably, it is interesting that exhibits excellent tetracycline degradation properties under visible light. Ultraviolet-visible diffuse reflectance spectroscopy and valence band X-ray photoelectron spectroscopy were carried out to investigate the photodegradation mechanisms. Moreover, a rational explanation for the fluorescent probe and photocatalysis behavior of these two complexes was also discussed with the assistance of density functional theory calculations.