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By utilizing symmetrical pentacarboxylate ligands, 3,5-di(2′,5′-dicarboxylphenyl)benzoic acid (H5L1) and 3,5-di(2′,4′-dicarboxylphenyl)benzoic acid (H5L2), two novel porous Zn-MOFs, [Zn5(μ3-H2O)2(L1)2]·3DMA·4H2O (CTGU-3) and [Zn3(μ3-OH)L2(H2O)3]·H2O (CTGU-4) have been synthesized under solvothermal conditions. CTGU-3 and CTGU-4 exhibit 3D microporous frameworks with flu and dia topologies and possess unique secondary building units [Zn5(μ3-H2O)2(RCO2)6] and [Zn3(μ3-OH)(RCO2)3], respectively. Such porous systems create a unique space or surface to accommodate Ag nanoparticles (Ag NPs), which could efficiently prevent Ag NPs from aggregation and leaching. In this work, two new Ag@Zn-MOF composites, denoted as Ag@CTGU, have been successfully fabricated through solution infiltration, for the reduction of nitrophenol. Compared with CTGU-4, CTGU-3 shows enhanced catalytic efficiency toward the reaction when it is used as a catalyst support of Ag NPs. Moreover, gas sorption and luminescence properties of two compounds were also investigated. [ABSTRACT FROM AUTHOR]

Despite tremendous progress in metal–organic frameworks, only limited success has been achieved with metal-chalcogenide organic frameworks. Metal-chalcogenide organic frameworks are desirable because they offer a promising route towards tunable semiconducting porous frameworks. Here, four novel semiconducting chalcogenide-organic hybrid compounds have been synthesized through a solvothermal method. Multitopic organic molecules, i.e., 1,2-di-(4-pyridyl)ethylene (L1), 1,3,5-tris(4-pyridyl-trans-ethenyl)benzene (L2) and tetrakis(4-pyridyloxymethylene)methane (L3), have been used as linkers to assemble Zn(SAr)2 or Zn2(SAr)4 units to generate different patterns of spatial organizations. Single-crystal structural analyses indicate that compounds NTU-2, NTU-3 and NTU-4 possess two-dimensional layer structures, while compound NTU-1 adopts a one-dimensional coordination framework (NTU-n, where n is the number related to a specific structure). The diffuse-reflectance spectra demonstrate that these four compounds possess indirect bandgaps and their tunable bandgaps are correlated with their compositions and crystal structures. [ABSTRACT FROM AUTHOR]

By one-step pyrolysis of a unique “cage-in-cage” cobalt metal–organic framework, nitrogen-doped carbon cubes embedded with numerous metallic Co nanoparticles were obtained. A considerable amount of Co particles was encapsulated in thin carbon shells and formed the core–shell-like Co@C structure. With about 60 wt% Co particles in the prepared sample, the nanocomposites of Co nanoparticles and nitrogen-doped carbon show electrocatalytic activity for the oxygen reduction reaction (ORR) with an efficiency comparable to the commercial Pt/C catalyst, but with better durability and methanol-tolerance performance. The metallic Co nanoparticles were found to play an important role in enhancing the ORR activity of the nanocomposites. This simple one-step pyrolysis method provides a novel synthetic route for the synthesis of core–shell-like Co@C nano-composites. The synthesized material represents a highly active non-precious metal catalyst for ORR. [ABSTRACT FROM AUTHOR]