Multifunctional Lanthanide Metal-Organic Frameworks Based on -NH 2 Modified Ligand: Fluorescent Ratio Probe, CrO 4 2- Ions Adsorption, and Photocatalytic Property.

In response to the growing concern for environmental pollution, two lanthanide compounds {[Ln(L)(H 2 O)]·4H 2 O} n (where Ln = Tb and Gd, H 3 L = 1-amino-2,4,6-benzene tricarboxylic acid) were synthesized using a -NH 2 modified ligand and systematically characterized. Both compounds exhibit remarkable fluorescence response, adsorption of CrO 4 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 Fe 3+ and CrO 4 2- /Cr 2 O 7 2- ions in aqueous solutions, while also serving as a ratiometric fluorescent probe for the detection of Cr 3+ , offering rapid response, high sensitivity, selectivity, and recoverability advantages in application. Moreover, 1-Tb exhibits excellent detection capabilities and displays effective adsorption of CrO 4 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.