Two new viologen-polyoxometalate hybrid crystalline materials: (MV)₂[HPW₂^ⅤW₁₀^ⅥO₄₀] ·2H₂O (1) and (EV)₂[Mo₈O₂₆] (2) have been synthesized by using the cations of 1, 1'-dimethyl-4, 4'-bipyridinium dichloride (methyl viologen, MV) and 1, 1'-diethyl-4, 4'-bipyridinium dibromide (ethyl viologen, EV) as the electron acceptors, and the electron-rich polyoxometalate anions as the electron donors. The structures of compounds 1 and 2 have been determined by single-crystal X-ray crystallography. Hydrogen bond interactions exist between the cations and the anions in 1 and 2. Interestingly, 2 has a photochromic performance with a light response time within 1 min. The photochromic mechanism of compound 2 has been investigated by solid-state diffuse reflection, electron paramagnetic resonance and theoretical calculation. 1 and 2 show good catalytic performance in the photocatalytic degradation of several organic dyes (methylene blue, pararosaniline hydrochloride and rhodamine 6G).

Two metal-organic frameworks (MOFs), trans-[Co(L)(μ₂-H₂O)(H₂O)₂]·2H₂O (1) and cis-[Mn(L)(Bipy)] (2) (H₂L=2, 2′-dimethyl-4, 4′-biphenyldicarboxylic acid, Bipy=4, 4′-bipyridine), have been synthesized and characterized by FTIR, thermogravimetric analysis (TGA), powder and single crystal X-ray diffraction. MOF 1 crystallizes in the triclinic system with a P1 space group and contains two crystallographically different Co(Ⅱ) ions. Each trans-[CoO₆] octahedron is connected by μ₂-H₂O and L^2- ligand with a bis(unidentate) coordination mode to produce a 2D sql topological network. MOF 2 crystallizes in the monoclinic system with a C2/c space group. The Mn(Ⅱ) cation adopts a cis-[MnO₄N₂] octahedron as a 6-connected node and is linked by L^2- ligand as a 4-connected node to generate a binodal (4, 6)-connected 3D fsc framework. The intermolecular interactions in 1 and 2 have been investigated by 3D Hirshfeld surface analyses and 2D fingerprint plots to reveal that the main interactions are H…H and O…H/H…O contacts in 1, and H…H and C…H/H…C contacts in 2. The TGA indicated that 1 and 2 were stable below 390 and 370 ℃, respectively.

2025年诺贝尔化学奖授予S. Kitagawa、R. Robson和O. M. Yaghi，以表彰他们在金属有机框架(Metal-Organic Frameworks，MOFs)开发方面的成就。作为21世纪的明星材料，MOFs因其巨大的比表面积、纳米级孔道以及多样的拓扑结构，在众多领域得以应用。作为最先进的多孔材料，MOFs的应用不再局限于气体吸附、分离和催化等传统领域，在大气集水、病原体检测和海水提铀等新兴领域也展现出广阔的应用前景。2013年，Yaghi在Science上发表了一篇有关MOFs最佳性能的重要综述。但从那以后，MOFs的性能又取得了重大突破。通过网状化学原理指导无机阳离子(节点)与有机配体(连接体)的组装，可以构筑混合组分的MOFs，使单组分MOFs优异性能的协同组合得以实现。将人工智能技术引入MOFs领域，能够为科学家们提供更多的机会，以快速设计和制造具有定制性能的新型MOFs。此外，基于反向MOFs设计策略(带负电荷的节点和带正电荷的配体)合成的新型多孔等网状non-MOFs材料将为MOFs材料开辟一个新的研究热点。

Three new 3-pyridazinyl-substituted triaryltriazoles, 4-(4-R-phenyl)-3-(2-pyridyl)-5-(3-pyridazinyl)-1,2,4-triazole (L¹: R=OCH₃; L²: R=H; L³: R=F) and their Cu(Ⅱ) complexes, trans-[Cu(L¹)₂(NO₃)₂]·H₂O (1), trans-[Cu(L²)₂(NO₃)₂] (2) and trans-[Cu(L³)₂(H₂O)₂](NO₃)₂ (3), have been synthesized and characterized by FTIR, ¹H NMR, elemental analysis and single crystal X-ray crystallography. Crystal structure analyses reveal that the supramolecular trimer (L¹)₃ and complex 3 crystallize in the triclinic P1 space group, the ligand L² and complexes 1 and 2 belong to the monoclinic P2₁/c space group, while the ligand L³ crystallizes in the monoclinic P2₁/n space group. There is a hydrogen-bonded trimer (L¹)₃ in the asymmetric unit of the ligand L¹. In the complexes 1-3, there is a distorted [CuN₄O₂] octahedron with two NO₃^- ions located in the axial positions in 1 and 2, whereas the two water molecules occupy the axial sites in 3. In the equatorial plane of 1-3, each L ligand adopts a chelating bidentate mode to bind the Cu(Ⅱ) ion through the pyridyl N atom and one triazole N atom, leaving the pyridazinyl group uncoordinated. The intermolecular interactions in the free ligands and the complexes have been explored by 3D Hirshfeld surface analyses and 2D fingerprint plots to reveal that the main intermolecular interactions are H…H and C…H/H…C contacts in (L¹)₃, H…H and N…H/H…N contacts in L², H…H, N…H/H…N and C…H/H…C in L³, H…H and O…H/H…O contacts in both 1 and 2, H…H, N…H/H…N and O…H/H…O contacts in 3.