Multifunctional Lanthanide Metal-Organic Frameworks Based on -NH₂ Modified Ligand: Fluorescent Ratio Probe, CrO₄^2-...

In response to the growing concern for environmental pollution, two lanthanide compounds {[Ln(L)(H₂O)]·4H₂O}_n (where Ln = Tb and Gd, H₃L = 1-amino-2,4,6-benzene tricarboxylic acid) were synthesized using a -NH₂ modified ligand and systematically characterized. Both compounds exhibit remarkable fluorescence response, adsorption of CrO₄^2- ions, and photocatalytic degradation properties, as well as exceptional acid-base and thermal stability. Remarkably, the pH-dependent 1-Tb exhibits exceptional performance as a fluorescent probe for detecting Fe³⁺ and CrO₄^2-/Cr₂O₇^2- ions in aqueous solutions, while also serving as a ratiometric fluorescent probe for the detection of Cr³⁺, offering rapid response, high sensitivity, selectivity, and recoverability advantages in application. Moreover, 1-Tb exhibits excellent detection capabilities and displays effective adsorption of CrO₄^2- ions, with a maximum adsorption capacity of 230.71 mg/g. On the other hand, 1-Gd exhibits superior performance compared to 1-Tb in the photocatalytic degradation of antibiotics. The degradation mechanism is further elucidated by conducting experiments with DFT theoretical calculations.