How to construct and control multinuclear dysprosium clusters with excellent single-molecule magnet (SMM) properties have been a great concern and challenge. Herein, we obtained two pyridine monoacylhydrazone ligands that are isomers of each other by a solvothermal in situ reaction, and the position of the N coordination site on the pyridine ring was controlled to achieve two binuclear dysprosium-based complexes with different SMM performance and cluster core connections. Specifically, 2-pyridinecarboxylhydrazide and 1-methyl-1H-imidazole-2-carbaldehyde undergo an in situ Schiff base reaction at 80 °C solvothermal conditions and coordinate with Dy­(NO3)3·6H2O to obtain a binuclear dysprosium complex [Dy2(L1)2(NO3)4(H2O)]­(HL1)·(H2O)2(CH3CN)2 (1) with a Dy2O2 cluster nucleus. In addition, the mononuclear dysprosium complex [Dy­(L2)­(NO3)2(H2O)2]·CH3CN (2) and binuclear dysprosium complex [Dy­(L2)2(NO3)]2·4CH3CN (3) were obtained by changing 2-pyridinecarboxylhydrazide to 3-pyridinecarboxylhydrazide and adjusting the solvent ratio of the reaction system. In the structure of binuclear dysprosium complex 3, Dy···Dy is not bridged by O atoms and has a long distance. Magnetic studies show that complexes 1–3 all exhibit field-induced SMM behaviors. Under the external field, the inversion energy barriers and relaxation times of complexes 1–3 are U eff = 22.40(6) K and τ0 = 7.33(1) × 10–5 s (1), U eff = 16.38(1) K and τ0 = 1.25(6) × 10–4 s (2), and U eff = 59.25(9) K and τ0 = 6.30(1) × 10–5 s (3), respectively. This work demonstrates that the design of the coordination sites for organic ligands is an effective strategy to tune the SMM properties of the polynuclear dysprosium complexes. It also provides a vivid example for the directional construction of multinuclear dysprosium complexes with SMM behaviors by in situ reactions in a black-box system.

The development of novel photocatalytic systems for energy-saving and efficient water purification and sterilization is extremely challenging but crucial for the prevention of chronic diseases caused by water pollution and bacteria. The self-aggregation of photosensitizers (PSs) driven by tight π−π stacking leads to a sharp decline in the ability to generate reactive oxygen species (ROS) and has become the main bottleneck for the application of PSs in photocatalytic water purification and sterilization. Herein, a series of porous anthracene-based metal− organic frameworks (MOFs) {[Zn(L) 2 (DEF) 2 ] n •2nDEF•nH 2 O (GXNU-1), [Co 2 (L) 4 (DEF) 2 ] n •4nDEF•8nH 2 O (GXNU-2), and [Ni(L) 2 (DEF) 2 ] n •nDEF•4nH 2 O (GXNU-3)} with excellent ROS generation ability were designed and synthesized.The energy level structures of GXNU-1−3 were determined by electrochemical experiments, which proved that all the frameworks have the ability to produce 1 O 2 . In addition, the photocurrent response and electrochemical impedance spectroscopy (EIS) proved that the formation of MOF structures can effectively enhance the charge separation ability and promote photogenerated holes and excitons under light-driven conditions, thereby further promoting the rapid generation of ROS. Their ability to catalyze the rapid purification and sterilization of high-concentration dye wastewater under low-power (60 mW•cm −2 ) light irradiation was then determined. The porous framework structure prevents the tight π−π stacking of anthracene-based PSs and increases the contact sites with oxygen. Moreover, the introduction of metal ions promotes the intersystem crossing of excitons through spin−orbit coupling. These advantages greatly enhance the ROS generation ability of GXNU-1−3 in aqueous solutions. Notably, GXNU-1−3 almost completely degraded highconcentration organic dyes, such as crystal violet (CV), methylene blue (MB), rhodamine B (RhB), and orange II (OII). In addition, GXNU-1 efficiently degraded mixed organic dyes of CV (30 mg•L −1 ) and MB (10 mg•L −1 ) within 30 min of light irradiation, thereby showing a surprising ability to purify multicomponent dye wastewater. The heterogeneous GXNU-1−3 can be rapidly separated from the aqueous solution by centrifugation and filtration to avoid secondary pollution. More notably, GXNU-1 can effectively inhibit the rapid proliferation of Gram-negative/positive bacteria under light irradiation conditions. Masks and experimental clothes soaked in a GXNU-1 aqueous solution for 15 s clearly resisted bacterial contamination after being exposed to 60 mW•cm −2 light irradiation for 4 min. These findings open new horizons for the construction of novel photocatalytic systems that are fast, efficient, and environmentally friendly.