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The first mixed-valence nickel-supported polyoxometalate-based metal–organic framework, (H2mim)[NiIII(Hmim)4][SiW11NiIIO37(OH)2(Hmim)]·3H2O (1) (Hmim = 2-methylimidazole), has been synthesized using a steam-assisted conversion method, and is constructed from noncovalent interactions (hydrogen bonds and π…π stacking interactions). 1 has a repeating honeycomb-shaped internal structure with one-dimensional channels along the direction of the c axis, where the diameter of the aperture is as large as 18.83 Å. Furthermore, the stability and the optical band gaps are investigated. [ABSTRACT FROM AUTHOR]

A series of organic–inorganic hybrid compounds built from Keggin and Wells–Dawson polyoxometalates and TM-trz complexes (Htrz = 1,2,4-triazole) were obtained at different pH values under hydrothermal conditions, namely, [Co2(H2O)2(Htrz)5][SiW12O40]·2.5H2O (1), [Zn5(Htrz)8(trz)2(H2O)8][SiW12O40]2·10H2O (2), [CuI2CuII4(Htrz)4(trz)4Cl2][GeW12O40]·15H2O (3), [CuI2CuII4(Htrz)4(trz)4Cl2][SiW12O40]·15H2O (4), K2Na2(H2O)2[Co11(trz)14(H2O)14][P2W18O62]2·29H2O (5) and [Cu12(trz)10(Htrz)2(OH)4(SO4)2(H2O)6][P2W18O62]·28H2O (6). All of the compounds were characterized using single-crystal X-ray diffraction, TG analysis and powder X-ray diffraction. Compound 1 contains a kind of bimetallic–organic segment [Co2(Htrz)5]4+, which could be regarded as a quasi-sinusoid-like chain. 2 is a dimer constructed from two [SiW12O40]4− units linked by a [Zn5(trz)2(Htrz)8]8+ motif. In 3 and 4, the 2D wall-like layers constructed by the Cu(ii) ions and Htrz ligands are extended into 3D frameworks by polyanions. 5 shows a complicated three-dimensional (3D) framework with a {412·612·84}{46}2 topology. Compound 6 is also a complicated 3D structure based on a triangular trinuclear Cu-trz unit and [P2W18O62] polyanions. To the best of our knowledge, 6 represents the largest copper cluster linked by amines in a POM system. Structural diversities reveal that the pH value of the reaction system plays a crucial role in the assembly of POM-based hybrids. Moreover, the optical band gaps, electrochemical properties, magnetic properties and the photocatalytic properties of the compounds have been investigated. [ABSTRACT FROM AUTHOR]

Three novel self-catenated 4-connected uninodal (65·8)-mok metal–organic rotaxane frameworks (MORFs) containing cucurbit[6]uril were constructed from the in situ trans/cis-configuration (1 : 1) of rotaxanes by taking advantage of a d10 metal ion directed synthesis. It was revealed that the effect of hydrogen bonds and π–π stacking interactions play significant roles in the self-assembly process. [ABSTRACT FROM AUTHOR]

A new three-dimensional metal–organic framework constructed form pentanuclear tetrahedral cluster and linear dicarboxylic acid ligand, [Zn 5 (btz) 6 (ndc) 2 (H 2 O)]·3DMA ( 1 ) (btz = benzotriazole, H 2 ndc = 1,4-naphthalenedicarboxylic acid) has been synthesized by the modular building blocks (MBBs) strategy under the solvothermal condition. Single X-ray diffraction reveals that 1 is a two-fold interpenetrated framework with mdf topology, in which pentanuclear {Zn 5 (btz) 6 } cluster acts as a 4-connected node. Moreover, the luminescent properties of 1 dispersed in different metal ions and solvents have been investigated systematically. [ABSTRACT FROM AUTHOR]