Reasonably designing highly pH-stable lanthanide metal−organic frameworks (Ln-MOFs) is of great importance for multifunctional applications. Herein, three isostructural Ln-MOFs, namely, {[Ln(tcmb)(H 2 O) 2 ]•2H 2 O} n (1-Ln, where Ln = Eu, Tb, Gd), have been synthesized and characterized. Experiments results showed that 1-Tb displayed high thermal, pH, and luminescence stability, which provided the possibility for its practical application. Because of the excellent luminescence performances of Ln-MOFs, the luminescent sensing and photocatalytic properties were investigated. 1-Tb exhibits high sensitivity, selectivity for sensing Fe 3+ , CrO 4 2− /Cr 2 O 7 2− ions in the presence of other competition ions. In addition, 1-Gd demonstrates the high photocatalytic activity for degrading tetracycline (TC) under visible light, with the degradation efficiency achieving 82% approximately. To prepare multicolor luminescence materials, by adjusting the relative proportion of Eu 3+ and Tb 3+ we constructed bimetallic Ln-MOFs 1-Eu x Tb 1−x with excellent linear color tunability from green to red, suggesting that 1-Eu x Tb 1−x can be the candidates for optical imaging and barcode research.

Two isomorphic lanthanide compounds {[Ln­(ddpp)­(H2O)]·CH3CN} n (Ln = Eu and Gd, H4ddpp = 2,5-di­(2′,4′-dicarboxylphenyl)­pyridine) were synthesized. Complex 1-Eu displays ultrahigh acid–base stability and thermal stability. Furthermore, luminescence measurements revealed that 1-Eu 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 Eu3+ ion of the ligand. Remarkably, it is interesting that 1-Gd 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.

Luminescent metal–organic frameworks (LMOFs) have been widely developed in the field of chemical sensing owing to their outstanding photoluminescence performance, high selectivity, anti-interference, high sensitivity, and fast response, and have become one of the research hotspots of emerging functional materials. However, in practical applications, many tests are carried out in the water environment, and fragile water stability greatly limits the application of MOFs in the field. Therefore, it is important to develop a method to enhance the water stability of MOFs. Herein, a new complex {[Zn(L)]·CH3CN}n (Zn-MOF, H2L = 5-(benzimidazol-1-yl) isophthalic acid) with a superior photophysical property has been synthesized first. Its water stability was highly enhanced by the doping of CuII ions by the one-pot method. In addition, the detection performances of doping material Cu0.1/Zn-MOF for sixteen metal ions and thirteen antibiotics were well studied. It was found that Cu0.1/Zn-MOF displays high sensitivity, fast response, lower detection limit, and long-term stability for the detection of Fe3+, NFT, NFZ, FZD, and TC in the aqueous medium.

Photocatalytic degradation of pollutants is an effective environment purification strategy. Metal−organic frameworks (MOFs) have attracted extensive attention in the field of photocatalysis owing to their structural diversity, uniform cavity, and large specific surface area. However, poor electrical conductivity, light absorption, and water stability restrict their development. The tailorable structure of MOFs may effectively overcome these limitations. Herein, three Cu-based MOFs (complexes 1−3) with one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) structures, respectively, were successfully prepared by introducing different uncoordinated ligands and adjusting the ligand/metal salt ratio. Among them, complex 1 with a 1D chain was constructed as a typical J-type aggregation by π−π stacking interactions between adjacent naphthalene rings. This intermolecular aggregation mode enhances strong exciton coupling between conjugated rings, reduces the transition energy, expands the intrinsic light absorption edge, and provides a channel for electron transport, thus improving the charge-separation efficiency. As expected, complex 1 with a 1D chain structure exhibited excellent Fenton-like catalytic activity. The apparent reaction rates were 3.2 and 2.0 times higher than those of 2D and 3D MOFs, respectively.