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Two unusual α-Keggin-based compounds with multinuclear silver clusters, {[Ag7(H2biim)5][PW11O39]}·Cl·H3O (1) and {[Ag2(H2biim)2][Ag(phnz)](PW12O40)}·H2O (2) (H2biim = 2,2′-biimidazole, phnz = phenazine), have been hydrothermally synthesized and structurally characterized by elemental analyses, IR spectra, thermogravimetric analysis and X-ray crystallography. Compound 1 displays a 2D network featuring dimerized monolacunary Keggin anions {PW11O39}2 which are connected together through pentanuclear silver clusters. Interestingly, besides {Ag5}5+ clusters, there are another kinds of argentophilic {Ag4}4+ clusters coexisting in compound 1. Compound 2 consists of four subunits: 1D cationic chains [Ag(phnz)]+, dinuclear silver-H2biim units [Ag2(H2biim)2]2+, discrete polyanions {PW12O40}3− and water molecules, which are further joined by hydrogen bonds to form a 3D supramolecular structure. The differences in the structures of compounds 1 and 2 indicate that the introduction of the secondary organic ligand plays a key role in determining the final structure. The electrochemical, electrocatalytic behaviors and luminescent properties of compounds 1 and 2 have also been investigated. [ABSTRACT FROM AUTHOR]

Abstract: A Wells–Dawson type polyoxoanion-based hybrid compound, Cu9(μ 2-OH)4(μ 3-OH)2(H2O)8(Hptz)8(P2W18O62)2·30H2O (ptz = 5-(4-pyridyl)-tetrazolate) (1), has been hydrothermally synthesized and characterized by routine methods. In compound 1, a novel nonanuclear copper cluster is constructed from two tetranuclear [Cu4(μ 2-OH)(μ 3-OH)(Hptz)3]6+ moieties, linked to each other though one Cu4 ion with the aid of two μ 2-OH and two ptz ligands. Then the P2W18 polyoxoanions bridge the nonanuclear copper clusters into a 1D ladder-like chain, in which the polyoxoanions and nonanuclear clusters act as two sides and middle rail of the ladder, respectively. The 1D chain is extended to a 3D supramolecular structure via hydrogen bonding interactions. The electrochemical property and magnetic behavior of compound 1 have been studied. [Copyright &y& Elsevier]

Abstract: Two isostructural Keggin-templated compounds containing a chair-like heptanuclear silver complex, [{Ag7(Hbtz)2(btz)4}{PM12O40}]·H2O (M=W, 1; Mo, 2) (Hbtz=benzotriazolate), have been hydrothermally synthesized and characterized by routine methods and single crystal X-ray diffraction. In the compounds 1 and 2, the Hbtz ligands present two types of coordination modes. A pentameric silver chain with two kinds of Ag⋯Ag weak interactions exists in the heptanuclear silver complex. The heptanuclear silver cations connect the polyoxoanions PM12O40 3− to a two-dimensional layer, and the adjacent layers are fused together by the pseudo wave-like chains, H-bonds and AgI–π interactions, constructing a three-dimensional net. Furthermore, electrochemical properties have been studied for compounds 1 and 2 and the two compounds display excellent electrocatalytic activities to the reduction of nitrite. [Copyright &y& Elsevier]

Abstract: Three compounds, [Na(bie)]2H[PW12O40] (1), [Cu(bie)]4[SiW12O40] (2) and [Cu(bie)]3H2[H3W12O40] (3) (bie=2,2′-bis(1H-imidazolyl)ether) have been hydrothermally synthesized by introducing different metal cations and polyanions, and characterized by routine physical methods. Their crystal structures have been established by single crystal X-ray diffraction. Compound 1 shows a 1D infinite chain which is composed of Na-bie coordination polymers and PW12 polyanions. By using the CuI cation, compounds 2 and 3 which show the 2D layer architectures were obtained. Due to the different polyanions of compounds 2 and 3, the topologies of the 2D layers are distinct. Further, the electrochemical properties of compounds 1–3 were studied. [ABSTRACT FROM AUTHOR]

Abstract: By employing different organic amines as structure-directing agents, two new distinct 3D porous inorganic frameworks based on molybdenum(V) phosphates and MnII, (H2en)2{[Mn(H2O)]2[MnMo12O24(OH)6(H2PO4)2(HPO4)4(PO4)2]}·7H2O (en=ethylenediamine) (1) and (H3dien)2{[Mn(H3O)2][Mn3Mo12O24(OH)6(HPO4)2(PO4)6]}·5H2O (dien=diethylenetriamine) (2), have been hydrothermally synthesized, and characterized by routine physical methods. In compound 1, MnII all adopt octahedral coordination mode and each sandwich cluster Mn[Mo6P4O31]2 (abbreviated as Mn[Mo6P4]2) acts as an octa-dentate ligand linking eight MnII, which result in a 3D inorganic (4, 8)-connected framework with the (46)(410·612·86) topology. Compound 2 shows a 3D (4, 10)-connected framework with the (31·44·61)(34·49·57·617·74·84) topology, in which MnII ions exhibit both tetrahedral and octahedral coordination modes, and each Mn[Mo6P4]2 links ten MnII. Interestingly, there exist channels along the a and b axes in 1, while along the a and c axes in 2. The differences between the two compounds should be ascribed to the distinctions of the organic amines. Primary de-/rehydration behaviors and electrochemistry properties have also been studied for the two compounds. [Copyright &y& Elsevier]

Abstract: Two new supramolecular compounds based on the Wells–Dawson polyoxometalate, [Cu(Hpbi)2]4[P2W18O62]2 (1) and (H2bbi)4[Cu2(bbi)(Hbbi)2][P2W18O62]2 (2) (pbi=1,1′-(1,3-propanediyl)bis(imidazole), bbi=1,1′-(1,4-butanediyl)bis(imidazole)), were hydrothermally synthesized and characterized by elemental analyses, IR spectroscopy, thermogravimetric analyses, and single X-ray diffraction. The [P2W18O62]6− polyanions in both compounds play the template role inducing the metal–organic coordination polymers to array around them. The polymers form 3D supramolecular frameworks with different voids in which the polyanions reside. The difference should be attributed to the different lengths of the two organic ligands. In addition, the electrochemistry properties of the two compounds were studied, which indicates that the supramolecular compounds keep the redox properties of their parent polyanions and exhibit the electrocatalytic activities toward the reduction of bromate and nitrite. [Copyright &y& Elsevier]

Abstract: Three new compounds, [Cu(C6H8N3O2)(C6H9N3O2)(H2O)2][Na(H2O)2]2[Al(OH)6Mo6O18]·6H2O (1), [Cu(C6H8N3O2)(C6H9N3O2)(H2O)2][Na(H2O)]2[Cr(OH)6Mo6O18]·3H2O (2) and [Cu(C6H10N3O2)(C6H9N3O2)(H2O)2][Al(OH)6Mo6O18]·9H2O (3) have been synthesized and characterized by elemental analyses, IR, TG, and single crystal X-ray diffraction. In the structures of compounds 1 and 2, the sodium cations connected the Anderson-type polyoxoanions to form 1D zigzag chains, which are connected to 2D layers by the Cu-histidine complexes. Compound 3 is a contrast for them, when the reactant without sodium cations is used, a discrete structure is formed. [Copyright &y& Elsevier]

Abstract: Two new compounds based on Weakley-sandwich-type polyanion (WSP), H2[Mn(en)2]2[Mn(en)2(H2O)]2[Mn4(H2O)2(PW9O34)2]·9H2O (1) and Na2[Co(en)2]2[{Co(en)2(H2O)]2[Co4(H2O)2(PW9O34)2]·9H2O (2) (en=ethylenediamine), have been synthesized by the hydrothermal reaction of the trivacant Keggin polyoxoanion [a-A-PW9O34]9− with transition metal ions and en, and structurally characterized by routine physical methods and single-crystal X-ray diffraction. Compound 1 represents a 1D chain structure made up of WSPs and [Mn(en)2]2+ ions. Compound 2 represents a 2D layer structure formed by the interconnection of WSPs, [Co(en)2]2+ and Na+ ions. Compounds 1 and 2 represent the first example of high-dimensional construction based on WSPs and transition metal complexes (TMCs), in which the water molecules located on the featured tetra-metal unit are still remained, and exhibit the property of sorption/desorption of water molecules. [Copyright &y& Elsevier]

Abstract: A new hybrid constructed from Wells–Dawson polyanions and silver complexes, [Ag(bipy)]2[Ag(bipy)(Hbipy)][P2W18O62]·[H2bipy] (1) (bipy=4,4′-bipyridine), has been hydrothermally synthesized, and characterized by IR, TG, XRPD and single-crystal X-ray diffraction. Structural analysis reveals that compound 1 possesses left- and right-helical chains constructed by Ag(bipy) complexes. Furthermore, these helical chains are linked together by Ag atoms via sharing O atoms of the Wells–Dawson polyanions to form two-dimensional (2D) sheets. Finally, a 3D framework is obtained with (41·64·81)(46·62·82·105) topology, which is constructed by the 2D sheets through the O atoms of the Wells–Dawson polyanions. Also, the electrochemical behavior and electrocatalysis of 1 modified carbon paste electrode (1-CPE) have been studied in detail. The results indicate that 1-CPE has remarkable stability and good electrocatalytic activities. [Copyright &y& Elsevier]

Abstract: An inorganic–organic hybrid complex, {[Cu2(phen)2(OH)2(H2O)]2[α-SiW12O40]}·8H2O 1, (phen=1,10-phenanthroline), has been synthesized under mild reaction conditions and characterized by single-crystal X-ray diffraction, IR spectrum, thermal analyses (TG-DTA) and fluorescent measurement. The crystallographic analysis reveals that in the compound, the Keggin polyanion [α-SiW12O40]4− acts as the inorganic building block, two [Cu2(phen)2(OH)2(H2O)] units covalently bond to it via terminal oxygen atoms of the Keggin anion. An open framework is formed through supramolecular interactions with solvent accessible volume of 18% in the unit-cell. Dehydration and re-adsorption of water in 1 were investigated by X-ray powder diffraction (XRPD).The compound shows thermal stability and photoluminescence property in the solid state. [Copyright &y& Elsevier]

Abstract: A new compound, {[Cu2(DF)2H2O]2SiMo12O40} (1) (DF=4,5-diazafluoren-9-one), has been hydrothermally synthesized and characterized by routine methods and single crystal X-ray diffraction. In 1, all the DF only adopt the unusual bidentate coordination mode for the first time coordinating to Cu atoms to form copper-dimers which link [SiMo12O40]4− clusters obtaining an intertwined double chain. Furthermore, the luminescent and electrochemical properties of the title compound have been studied. [Copyright &y& Elsevier]

Abstract: This article reports two new bicapped Keggin-based hybrid compounds, {[Cu4 I(cppy)4][PMo7 VIMo5 VO40(VIVO)2]}·2H2O (1) and {[Cu4 I(cppy)4][SiMo8 VIMo4 VO40(VIVO)2]}·2H2O (2) (cppy=4-(5-(4-chlorophenyl)pyridin-2-yl)pyridine), synthesized under hydrothermal conditions and characterized by X-ray single-crystal diffraction, elemental analyses, IR, XPS, TG and CV analyses. Structural characterization shows that the two compounds are isostructural, consisting of square tetranuclear [Cu4 I(cppy)4]4+ circuits and reduced bivanadyl Keggin clusters. The tetranuclear [Cu4 I(cppy)4]4+ circuit is ‘windstick’-style. The polyoxoanions acting as junctures connect the tetranuclear circuits to construct a chain. These chains are further connected through π⋯π interactions, halogen bonding and hydrogen bonding interactions to construct a 3D superamolecular structure. The electrochemical behaviors of the 1-CPE have been studied in detail. [Copyright &y& Elsevier]

Abstract: A new Cu-Nb mixed complex, [{Cu2(phen)4(μ-O)2(NbF4)2}(μ-F)][NbF6] (1) (phen=1,10-phenanthroline), was hydrothermally synthesized, and characterized by elemental analyses, IR spectra, thermogravimetric analysis and single crystal X-ray diffraction. Compound 1 exhibits a discrete barbell-like copper cluster with {(μ-F)[(μ-O)2(NbF4)2]} fragment as the handle bar, and [NbF6]− is a counter-anion. Fluorescent property, solubility, and electrochemical property of compound 1 were studied. [Copyright &y& Elsevier]

Abstract: A polyoxometalate-based compound, (bix)[Cu(bix)][Cu2(bix)2(P2W18O62)]·2H2O (1) (bix=1,4-bis(imidazol-1-ylmethyl)benzene), was hydrothermally synthesized, and characterized by elemental analyses, IR spectroscopy, thermogravimetric analysis, and single X-ray diffraction. Compound 1 exhibits the 1D+1D polypseudo-rotaxane structure consists of two parts: the P2W18–Cu2–(bix)2 chain which contains 26-membered Cu2(bix)2 macrocycles and the 1D Cu-bix line. Remarkably, it represents the first polypseudo -rotaxane structure based on the Wells–Dawson polyoxometalate. [Copyright &y& Elsevier]

Abstract: Two isostructural compounds based on Anderson polyoxoanions, [Cu(phen)]2[CrMo6H5O24] (1) and [Cu(phen)]2[AlMo6H5O24] (2) (phen=1,10-phenaanthroline), have been hydrothermally synthesized and characterized by IR, XPS, EPR spectra, TG analyses, magnetic susceptibility, and single-crystal X-ray diffraction. Compounds crystallize in the monoclinic space group P2(1)/n with a =5.66710(10)Å, b =21.3723(5)Å, c =14.7092(3)Å, β =98.10(10)°, V =1763.79(6)Å3, R 1 =0.0240, Z =2 and GOF =1.140 for 1, and in the monoclinic space group P2(1)/n with a =5.6641(3)Å, b =21.3346(13)Å, c =14.6909(9)Å, β =97.9120(10)°, V =1758.37(18)Å3, R 1 =0.0529, Z =2 and GOF =0.0994 for 2. Single crystal X-ray diffraction reveals that the compounds 1 and 2 are both built up of Anderson polyoxoanions and copper–phen complexes. The structural feature of 1 and 2 is that the Anderson polyoxoanions act as multidentate ligands linking copper–phen complex to form 1D chains. Compounds 1 and 2 not only represent new Anderson-type POM-supported transition metal organic–inorganic hybrid compounds with extend structure, but also verify the feasibility of constructing these compounds through hydrothermal methods. [Copyright &y& Elsevier]