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Three novel porous transition-metal-organic frameworks (TM-OFs), formulated as [Co 3 (DCPN) 2 (μ 2 -OH 2 ) 4 (H 2 O) 4 ](DMF) 2 ( 1 ), [Cd 3 (DCPN) 2 (μ 2 -OH 2 ) 4 (H 2 O) 4 ](DMF) 2 ( 2 ), and [CdK(DCPN)(DMA)] ( 3 ), have been successfully prepared via solvothermal conditions based on a 5-(3',6'-dicarboxylic phenyl) nicotinic carboxylic acid (H 3 DCPN) ligand. 1 and 2 both have the same porous 3D network structure with the point symbol of {4 10 ·6 14 ·8 4 }·{4 5 ·6} 2 based on trinuclear ({Co 3 } or {Cd 3 }) clusters, indicating a one-dimensional porous channel, and possess excellent water and thermal stability; 3 also displays a porous 3D network structure with a 4-connected sra topology based on the heteronuclear metal cluster {CdK}. Complex 1 can be used to load Pd nanoparticles (Pd NPs) via a wetness impregnation strategy to obtain Pd@ 1 . The reduction of nitrophenols (2-NP, 3-NP, 4-NP) by Pd@ 1 in aqueous solution shows outstanding conversion, excellent rate constants ( k ), and remarkable cycling stability due to the synergistic effect of complex 1 and Pd NPs. Luminescence sensing tests confirmed that 2 is a reliable multifunctional chemical sensor with high selectivity and sensitivity for low concentrations of Fe 3+ , Cr 2 O 7 2- , CPFX, and NFX. Specifically, 2 shows a fluorescence enhancement behavior toward fluoroquinolone antibiotics (CPFX and NFX), which has not been reported previously in the literature. Moreover, the rational mechanism of fluorescence sensing was also systematically investigated by various detection means and theoretical calculations.

Developing a new type of proton conductive material is key to improve the energy conversion performance of proton exchange membrane fuel cell (PEMFC). In recent years, metal organic framework (MOF) matrix conductive materials have become one of the research hotspots in the field of MOF. However, the grain boundaries in MOF particles and MOF@polymer composite films make it difficult to form long‐range ordered proton transport channels. Reducing crystallinity and changing the internal structural properties of MOF matrix may effectively improve its proton conductivity. In this study, some synthesis strategies were used to induce the crystallinity of MOF matrix to improve the proton conductivity, and low‐crystallinity MOG materials were obtained. In all, eight materials were prepared. The morphology characterization and proton conductivity of MOF and MOG materials were studied to explore the influence of different crystallinities and internal structures on proton conductivity. The results explicitly indicated that for the hydrophilic materials, the proton conductivity of MOG‐MOF‐808, MOG‐UiO‐66, MOG‐HKUST‐1 was significantly improved, compared with the corresponding MOFs at 75% RH. Among them, MOG‐MOF‐808 and MOG‐UiO‐66 show strong water stability and thermal stability, ensuring that it can be applied in special and complex environments. For the hydrophobic ZIF‐8 and MOG‐ZIF‐8, both their proton conductivities are low due to the material characteristics and network structures, while the proton conductivity of MOG‐ZIF‐8 is also higher than that of ZIF‐8 at 303 K. The results show that the abundant low‐crystallinity network structure in MOG materials played a very important role in improving the proton conductivity of the hydrophilic materials. Highlights: MOG materials have higher proton conductivity than MOFs at 75% RH. At 303 K, the conductivity of MOG‐MOF‐808 (1.35×10−2 S·cm−1) increased 196% relative to MOF‐808, and MOG‐UiO‐66 (3.89×10−3 S·cm−1) is about 73 times that of UiO‐66.The three‐dimensional MOG structure has a coherent three‐dimensional hydrogen bonding network, which can provide long‐range ordered proton transfer channels and enhance proton transfer efficiency.Improving proton conductivity of MOF materials by reducing crystallinity provided a new idea for the design and adjustment of proton conductivity of MOF materials. [ABSTRACT FROM AUTHOR]

Two series of lanthanide-based metal–organic frameworks, namely {[Ln(BIPA-TC)0.5(DMA)2(NO3)]·DMA·H2O}n (1-Ln, Ln = Eu, Dy, Sm, Nd) and {[Ln2(BIPA-TC)1.5(DMA)3(H2O)2]·2DMA·2H2O}n (2-Ln, Ln = Eu, Dy, Sm, Nd), were successfully constructed via a solvent regulation strategy based on a π-electron rich tetra-carboxylate ligand (H4BIPA-TC). 1-Ln shows a 4-connected lvt topology with the point symbol of {42·84}, but 2-Ln displays a new 4,4,6-connected wxk1 topology with the point symbol of {43·83}4{46·66·83}2{86}. The solid-state luminescence property and the microporous nature of Eu-MOFs (1-Eu and 2-Eu) indicate that they can potentially be used as luminescent sensors. Fluorescence measurements indicate that Fe3+ exhibits the quenching effect for 1-Eu with the quenching efficiency of 93.1%. 2-Eu is the first MOF sensor for Mg2+ with the lowest detection limit of 1.53 × 10−10 mol L−1 and displays good recyclable capability. Simultaneously, in the presence of other metal ions (Ca2+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Pd2+, Al3+, Cr3+and Fe3+), 2-Eu can maintain the selective sensing of Mg2+, indicating its potential for Mg2+ turn-on sensing. [ABSTRACT FROM AUTHOR]

Two new two‐dimensional lanthanide coordination polymers, namely poly[[tetra‐μ2‐acetato‐tetraaquabis(μ4‐biphenyl‐3,3′,5,5′‐tetracarboxylato)tetrakis(dimethylacetamide)tetraterbium(III)] pentahydrate], {[Tb4(C16H6O8)2(C2H3O2)4(C4H9NO)4(H2O)4]·5H2O}n, (1), and poly[[tetra‐μ2‐acetato‐tetraaquabis(μ5‐biphenyl‐3,3′,5,5′‐tetracarboxylato)tetrakis(dimethylacetamide)tetraeuropium(III)] tetrahydrate], {[Eu4(C16H6O8)2(C2H3O2)4(C4H9NO)4(H2O)4]·4H2O}n, (2), have been synthesized from biphenyl‐3,3′,5,5′‐tetracarboxylic acid (H4bpt) and Ln(NO3)3·6H2O (Ln = Tb and Eu) under solvothermal conditions. Single‐crystal X‐ray structure analysis shows that the two compounds are isostructural and crystallize in the monoclinic P21/n space group. The crystal structures are constructed from bpt4− ligands (as linkers) and {Ln2(μ2‐CH3COO)2} building units (as nodes), which topological analysis shows to be a (4,6)‐connected network with sql topology. Compounds (1) and (2) have been characterized by elemental analysis, IR spectroscopy, powder X‐ray diffraction (PXRD), thermogravimetric analysis (TGA) and fluorescence analysis in the solid state. In addition, a magnetic investigation shows the presence of antiferromagnetic interactions in compound (1). [ABSTRACT FROM AUTHOR]