A new supramolecular compound based on Mn(II)-Schiff-base and Keggin-type [PMo12O40]3−

A new organometallic-inorganic hybrid compound {[Mn(L)₂]₂[PMo₁₂O₄₀][NO₃] · 4CH₃OH · 3H₂O} _n (I), where L is 1,4-bis(4-imidazolyl)-2,3-diaza-1,3-butadiene) was synthesized in situ from [PMo₁₂O₄₀]^3?, Mn²⁺ and L reaction in an H₂O-DMSO-CH₃OH mixture at room temperature, and the product was structurally characterized by elemental analysis, infrared spectroscopy, and single-crystal X-ray diffraction analysis. Compound I is constructed from alternating layers of the metal-Schiff-base cation and Keggin anions based on electrostatic forces and hydrogen bond interactions.     

Subtle difference of [SiMo12O40]4− and [PMo12O40]3− inducing two new distinct Keggin-Ag-(1H-Pyrazole) compounds

Two new inorganic-organic hybrid compounds based on α-Keggin clusters and Ag-(1H-Pyrazole) subunits, [AgL₂]₄[SiMo₁₂O₄₀] (1) and [AgL₂]₃[PMo₁₂O₄₀] (2) (L = pyrazole), have been synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction. In 1, there are two kinds of chains, the chains linked by two [AgL₂]⁺ clusters and the other linked only by one [AgL₂]⁺, which further connect by sharing [SiMo₁₂O₄₀]^4? anions to construct a 2-D layer. In 2, four-supporting [PMo₁₂O₄₀]^3? anions are fused by [Ag(1)L₂]⁺ subunits to form a 1-D chain. Through weak interactions of Ag?O (3.091 Å) a 2-D supramolecular layer is constructed. Additionally, the electrochemical properties of title compounds and the photocatalytic properties of 2 have been studied.     

Two new organic-inorganic hybrid compounds induced by γ-[Mo8O26]4− and [PMo12O40]3−

Two new organic–inorganic hybrid compounds, [Cu^II(btb)_1.5(γ-Mo₈O₂₆)_0.5(H₂O)]·2H₂O (1) and [Cu^II₂(btb)₄(PMo^VMo^VI₁₁O₄₀)]·2H₂O (2) (btb = 4-butyl-1,4-bis(1,2,4-triazole), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis, IR spectra and elemental analyses. In 1, there exists a ladder-like metal-organic chain with the bidentate [γ-Mo₈O₂₆]^4? anions inserting into the grids. Adjacent chains share the same Cu-btb lines of the ladder to form a 2-D layer. Compound 2 also has a ladder-like metal-organic chain. The tetradentate [PMo₁₂O₄₀]^3? anions embed in the grids. The same Cu-btb line is shared by adjacent chains to build a 2-D layer. The btb ligands link adjacent layers to form a 3-D framework. Moreover, we also have investigated the electrochemical and photocatalytic properties of 1 and 2.     

Assembly of three supramolecular compounds based on [P2Mo5O23]6− and Ni(II) complexes

Three supramolecular compounds based on [P₂Mo₅O₂₃]^6? and Ni(II)–bim, [Ni(bim)₃]₃[P₂Mo₅O₂₃]·2H₂O (1), [Ni(Hbim)(bim)₂]₄[P₂Mo₅O₂₃]₂·3H₂O (2), and [Ni(bim)(Hbim)(phen)]₂[P₂Mo₅O₂₃]·7H₂O (3) (bim?=?2,2′-biimidazole, phen?=?1,10-phenanthroline), have been synthesized under hydrothermal conditions and characterized by elemental analysis, single-crystal X-ray diffraction, IR, and TG. All the compounds show 3-D supramolecular networks constructed from weak interactions among free Ni(II) complex, water, and oxygens of [P₂Mo₅O₂₃]^6?. Compound 3 represents the first supramolecular example integrating {Ni(bim)(Hbim)(phen)} with Strandberg-type phosphomolybdate. The compounds display good electrocatalytic activity to reduce hydrogen peroxide and intense fluorescence properties in solution at room temperature.     

Two new supramolecular assemblies based on Keggin-type polyoxometalates through AgO and ππ stacking interactions

Two new supramolecular assemblies based on Keggin-type polyoxometalates, [Ag₃(4,4′-bipy)₂(2,2′-bipy)₂][Ag(2,2′-bipy)₂][{Ag(2,2′-bipy)}HSiW₁₁VO₄₀] (1) and [Ag₃(4,4′-bipy)₂(2,2′-bipy)₂][Ag(2,2′-bipy)₂][{Ag(2,2′-bipy)}PW₁₁VO₄₀] (2) (4,4′-bipy = 4,4′-bipyridine, 2,2′-bipy = 2,2′-bipyridine), have been synthesized under the hydrothermal conditions and structurally characterized by IR, XPS, TG and single-crystal X-ray diffraction. Compound 1 has a 2D layer network structure via weak Ag^...O interactions. Compound 2 is isostructural with compound 1. In addition, the fluorescence of compound 1 is reported.     

Synthesis and Structure of Two Keggin-Type Heteropolyanions: [VMo12O40]3n− n (1) and [H3PMoVMoVI 11O40]1− (2)

Two Keggin-type heteropolyanions were synthesized and characterized by X-ray crystal structure and elemental analysis as well as infrared spectroscopy. Both K₃[VMo₁₂O₄₀]19H₂O (1) and [N _i (H₂O)₆][H₃PMo^VMo^VI ₁₁O₄₀]₂30 H₂O (2) were prepared in aqueous solution. Compound 1 crystallized in the space group Pm-3m, a=10.6513(1) Å, V=1208.4(3) ų, Z=1. Compound 2 crystallized in the space group R-3 with a=b=13.9669(2) Å, c=42.0075(5) Å, V=7096.71(2) ų, Z=3. The compound 1 contains a {K₆VMo₁₂O₄₀} group in which six potassium ions form a regular {K₆} octahedron. The heteropolyanion [VMo₁₂O₄₀]^3– was capped by six potassium ions and enclosed by {K₆} octahedron. A three-dimensional structure was formed by the buildup of {K₃[VMo₁₂O₄₀]} _n . Compound 2 contains a one-electron reduced heteropolyanion [H₃PMo^VMo^VI ₁₁O₄₀]^1–. Ni²⁺ coordinated by six water molecules as the counter cation balances the negative charge of the molecule.     

A New Supramolecular Compound Based on Cd（II）-Schiff-base and Keggin-type [PMo_（12）O_（40）]~3

A new supramolecular compound, {[Cd(L)2]2[PMo12O40NO3]·CH3CN·2H2O}n 1 (L is 1,4-bis(4-imidazolyl)-2,3-diaza-1,3-butadiene), based on Cd(II)-Schiff-base and Keggin- type [PMo12O40]3- was synthesized via self-assembly and structurally characterized by elemental analysis, infrared spectroscopy, and single-crystal X-ray diffraction analysis. The crystal is of triclinic, space group P1 with a = 12.0128(11), b = 13.6196(13), c = 13.9995(13) , α = 103.868(2), β = 95.225(2), γ = 101.024(2)°, V = 2160.0(3) 3, Z = 1, C34H39N26O45Cd2Mo12P, Mr = 2938.96, Dc = 2.259 g/cm3, μ = 2.276 mm-1, F(000) = 1400, the final R = 0.0565 and wR = 0.1613 for 4973 observed reflections with I 2σ(I). The crystal structure can be described by the packing of Keggin anionic and Metal-Schiff-base cationic layers.     

Solvent-dependent assembly of porous coordination polymers based on Keggin-type [SiW12O40]4–

Two coordination polymers (CPs) based on Keggin-type [SiW₁₂O₄₀]^4– (SiW₁₂), [Zn₂(bpy)₂(SiW₁₂O₄₀)(DMF)₈]·solvent (1) and [Zn₂(bpy)(SiW₁₂O₄₀)(DMA)₈]·2DMA (2) (bpy = 4,4′-bipyridine, DMF?=?N,N′-dimethylformamide; DMA?=?N,N′-dimethylacetamide), have been solvo-thermally synthesized and characterized by single crystal X-ray diffraction, powder X-ray diffraction, IR spectra, elemental analyses and thermogravimetric analyses. Both 1 and 2 are synthesized under similar conditions except DMF and DMA were used as the solvents for 1 and 2, respectively. Structural studies reveal that the supramolecular framework of 1 contains pumpkin-like voids, while 2 has a non-porous supramolecular framework. These results show that solvents play an important role in construction of the POM-based CPs. The luminescent properties for 1 and 2 have also been investigated.     

[Co(phen)3]2[PMo12O40](OH)的水热合成及晶体结构

利用水热合成法制备了Keggin结构阴离子有机一无机复合物[Co（phen）3]2[PMo12O40]（OH）,通过元素分析,红外光谱和X射线单晶衍射等对其进行了表征．结果表明,该化合物属于单斜晶系,C2／c空间群．=1．97225（18）nm,b=1．81079（16）nm,c=2．5117（2）nm,β=100．5380（10）°,V=8．819O（14）nm^3,Z=4,R1=0．0587,wR2=0．1211．该化合物分子由一个多阴离子[PMo12O40]^3-,两个[Co（phen）3]^2＋及一个羟基组成．     

Crystal structure and properties of H3[PMo12O40] · 3C2H6O

The title compound H₃[PMo₁₂O₄₀]· 3C₂H₆O was prepared and characterized by X-ray crystallography, its i.r. spectrum, cyclic voltammetry and e.s.r. spectra. The anion of the title compound is a Keggin-type heteropoly structure based upon a central PO₄ tetrahedron surrounded by 12 MoO₆ octahedra arranged in four groups of three edge-shared octahedra Mo₃O₁₃. Weak hydrogen bonds exist between the organic solvent molecules and the heteropoly anion. The catalytic activity of the title compound was determined by the synthesis of butyl acetate. The conversion of n-BuOH reached 93.3% and the yield of MeCO₂Bu-n was 92.0% when the ratio of MeCO₂H to n-BuOH, catalyst amount, reaction time, reaction temperature were 2:1, 0.24% of the reactants (50 mg), 2.0 h and 115 120 °C, respectively.     

A series of new organic–inorganic compounds templated by the [SiW12O40]4− polyanion

Two couples of new compounds templated by the polyanion [SiW₁₂O₄₀]^4?,[Hbix][Cu^I(bix)]₃[SiW₁₂O₄₀]·4H₂O (1) and [Cu^II(H₂O)(Hbix)₂(bix)]₂[Cu^II(H₂O)₂(Hbix)₂(bix)][SiW₁₂O₄₀]₃·4H₂O (2) (bix = 1,4-Bis(imidazol-1-ylmethyl)benzene), [Cu^I(bbi)]₄[SiW₁₂O₄₀]·2H₂O (3) and [Cu^II(bbi₂)]₂[SiW₁₂O₄₀] (4) (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. Compounds 1 and 2 were synthesized from the same reactants but exhibited distinct structures which could be ascribed to the different ratios of the reactant bix to Cu^II. In compound 1, the higher ratio of bix results in the transformation of the Cu^II to Cu^I, the [SiW₁₂O₄₀]^4? templates direct the Cu^I–bix coordination polymers to form a 3D supramolecular framework with grid-like channels along two directions. The [SiW₁₂O₄₀]^4? templates in compound 2 locate in the voids of the 3D supramolecular network constructed by Cu^II–bix coordination polymers, which exhibits the interdigitation fashion in both the formation of the 2D layer and the 3D framework. Compounds 3 and 4 were synthesized similar to 1 and 2, except for the change of bix to bbi. In compound 3, the Cu^I–bbi polymers form a supramolecular metal–organic host framework with rhombic channels in which the SiW₁₂ templates reside. Compound 4 shows a framework with hexagonal channels constructed by Cu^II–bbi coordination polymers which accommodated the SiW₁₂ templates.     

Double-Shelled Hollow SiO2@N-C Nanofiber Boosts the Lithium Storage Performance of [PMo12O40]3−

Polyoxometalates (POMs)-based materials, with high theoretical capacities and abundant reversible multi-electron redox properties, are considered as promising candidates in lithium-ion storage. However, the poor electronic conductivity, low specific surface area and high solubility in the electrolyte limited their practical applications. Herein, a double-shelled hollow PMo₁₂−SiO₂@N−C nanofiber (PMo₁₂−SiO₂@N−C, where PMo₁₂ is [PMo₁₂O₄₀]³⁻, N−C is nitrogen-doped carbon) was fabricated for the first time by combining coaxial electrospinning technique, thermal treatment and electrostatic adsorption. As an anode material for LIBs, the PMo₁₂−SiO₂@N−C delivered an excellent specific capacity of 1641 mA h g⁻¹ after 1000 cycles under 2 A g⁻¹. The excellent electrochemical performance benefited from the unique double-shelled hollow structure of the material, in which the outermost N−C shell cannot only hinder the agglomeration of PMo₁₂, but also improve its electronic conductivity. The SiO₂ inner shell can efficiently avoid the loss of active components. The hollow structure can buffer the volume expansion and accelerate Li⁺ diffusion during lithiation/delithiation process. Moreover, PMo₁₂ can greatly reduce charge-resistance and facilitate electron transfer of the entire composites, as evidenced by the EIS kinetics study and lithium-ion diffusion analysis. This work paves the way for the fabrication of novel POM-based LIBs anode materials with excellent lithium storage performance.     

Two new Cu(II) m-hydroxybenzoato complexes with chloro- and carboxylato-bridged dinuclear [Cu(µ2−Cl)(µ2−COO)Cu] cores

In aqueous methanolic solution, reactions of CuCl₂, m-hydroxybenzoic acid (HL), and NaOH with 2,2'-bipyridine (bpy) and 1,10-phenanthroline (phen) at room temperature afforded {[Cu(bpy)L](µ₂?Cl)(µ₂?L)[Cu(bpy)L]}?1.2H₂O (1) and {[Cu(phen)Cl](µ₂?Cl)(µ₂?L)[Cu(phen)L]} (2) with chloro- and carboxylato-bridged dinuclear [Cu(µ₂?Cl)(µ₂?COO)Cu] cores. The Cu₂ dimers in 1 are pairwise aggregated to form H-bonded tetranuclear motifs, which are extended by H₂O into 1-D H-bonded chains and further assembled into 2-D supramolecular networks. The Cu₂ dimers in 2 are also linked into 1-D H-bonded chains and further assembled into 2-D supramolecular layers. Magnetic measurements indicate that significant antiferromagnetic interactions (J = ?15.9, ?12.2 cm^?1) between Cu²⁺ ions are dominant in these dinuclear [Cu(µ₂?Cl)(µ₂?COO)Cu] cores. To the best of our knowledge, 2, crystallizing in the acentric polar orthorhombic space group Pna2₁, represents the first example of metal m-hydroxybenzoato complexes with ferroelectric properties with a remnant polarization (Pr) of ca. 0.04?µC cm^?2, coercive field (Ec) of ca. 2.52 kV cm^?1, and saturation of the spontaneous polarization (Ps) at ca. 0.195?µC cm^?2.     

Formation of [FeW12O40]5− under hydrothermal conditions: syntheses,crystal structures,and characterization of [Fe(2,2′-bipy)3]2[HFeW12O40] · 5H2O and (4,4′-H2bipy)6(Hpy)2(H3O)[FeW12O40]3 · 11H2O

Two supramolecular compounds based on tungstoferrate [FeW₁₂O₄₀]^5?, [Fe^II(2,2′-bipy)₃]₂[HFeW₁₂O₄₀] · 5H₂O (1), and [Hpy]₂[4,4′-H₂bipy]₆(H₃O)[FeW₁₂O₄₀]₃ · 11H₂O (2) (py = pyridine, bipy = bipyridine) were synthesized hydrothermally and characterized structurally. The hydrogen bonds between polyoxoanions and water and the edge-to-face π–π interaction between [Fe^II(2,2′-bipy)₃]²⁺ with a shortest C–C distance of 3.513 Å are the main forces to construct the 3-D architecture of 1. In 2, a 3-D supramolecular architecture is assembled by the tungstoferrate anions, protonated 4,4′-bipy cations, and water through hydrogen bonding. The variable-temperature magnetic susceptibilities indicate that 1 is paramagnetic with μ _eff corresponding to one Fe(III) with spin-only contribution, showing that Fe in the coordination cations has a +II oxidation number and low spin state.     

超分子化合物(C10N2H9)3[PMo12O40]·3H2O合成与表征

利用水热方法合成了超分子化合物(C10N2H9)3[PMo12O40]·3H2O,通过元素分析、ICP和X射线单晶衍射确定了其晶体结构,并通过IR和XRD进行了结构表征,采用热重分析和循环伏安曲线研究了晶体的热稳定性和氧化还原性．该化合物是由联吡啶、水以及[PMo12O40]3-阴离子组成,它们之间存在较强的氢键作用,自组装成超分子结构化合物．     

Hydrothermal Synthesis and Crystal Structure of a Novel Composite Keggin-type Arsenotungstate： [Ni（phen）2] [Hphen] （AsW12O40）

A novel polyoxometalate-based composite compound [Ni(phen)2][Hphen](AsW12O40) (phen = 1,10-phenanthroline) 1 has been hydrothermally synthesized and characterized by elemental analysis, IR, TGA, ESR spectroscopy and single-crystal X-ray diffraction. Each structure unit of 1 consists of one polyoxoanion AsW12O403-, one free phenanthroline molecule and one coordination cation [Ni(phen)2]2+. The title compound crystallizes in the orthorhombic system, space group P212121, with a = 12.2383(7), b = 21.0884(11), c = 22.3237(12) , V = 5761.4(5) 3, Mr = 3520.44, Z = 4, Dc = 4.059 g/cm3, F(000) = 6204, μ(MoKα) = 24.844 mm-1, GOF = 1.022, the final R = 0.0376 and wR = 0.0742 (I > 2σ(I)) for 865 parameters and 9637 observed reflections with I > 2σ(I).     

Hydrothermal syntheses and structural characterization of two new supramolecular compounds: (H2bbi)2[Mo8O26] and (H2bbi)2[SiW12O40]·2H2O [bbi = 1,1′-(1,4-butanediyl)bis(imidazole)]

Two new inorganic–organic hybrid supramolecular compounds based on imidazolium and POMs formulated as (H₂bbi)₂[Mo₈O₂₆] (1) and (H₂bbi)₂[SiW₁₂O₄₀]·2H₂O (2) [bbi = 1,1′-(1,4-butanediyl)bis(imidazole)] have been prepared under hydrothermal conditions and characterized by elemental analyses, IR and single-crystal X-ray diffraction analyses. The two compounds consist of protonated bbis together with POMs. [Mo₈O₂₆]^4? and [SiW₁₂O₄₀]^4? are linked through H₂bbi into a three-dimensional (3D) network via hydrogen bonds, respectively. Compound 1 is the first example of 3D two-fold interpenetrating hydrogen bond-supported supramolecular assembly from octamolybdate one-dimensional (1D) chain and imidazolium. The fascinating structural feature of compound 2 is that the anions and the protonated bbi ligands formed a 3D (4, 8) supramolecular network by hydrogen bonds. Compound 2 has been used as a solid bulk-modifier to fabricate three-dimensional bulk-modified carbon paste electrode (CPE) by direct mixing. The electrochemical behavior and electrocatalysis of compound 2 modified CPE (2-CPE) have been studied.     

An organic-inorganic hybrid polyoxometalate based on the dodecatungstate building block: [Ni(phen)(H2O)3]2[Ni(H2O)5][H2W12O40] · 6H2O

An organic-inorganic hybrid polyoxometalate [Ni(phen)(H₂O)₃]₂[Ni(H₂O)₅][H₂W₁₂O₄₀]?·?6H₂O (phen?=?1,10-phenanthroline) has been isolated and characterized by IR, UV, electrochemistry and single-crystal X-ray diffraction. X-ray crystallographic study indicates that the title compound is monoclinic, space group C2/c, with lattice constants a?=?21.7672(17), b?=?16.1189(12), c?=?20.7949(16)?Å, β?=?107.8440(10)°, V?=?6945.2(9)?ų, D _c?=?3.528?Mg?m^?3, F(000)?=?6600, Z?=?4, R ₁?=?0.0372, wR ₂?=?0.0845. The molecular fragment of the title compound consists of two supporting [Ni(phen)(H₂O)₃]²⁺ coordination cations, one supporting [Ni(H₂O)₅]²⁺ unit, one metatungstate polyoxoanion [H₂W₁₂O₄₀]^6? and six H₂O molecules of crystallization.     

[Ni(NHC)2] as a Scaffold for Structurally Characterized trans [H−Ni−PR2] and trans [R2P−Ni−PR2] Complexes

The addition of PPh₂H, PPhMeH, PPhH₂, P(para-Tol)H₂, PMesH₂ and PH₃ to the two-coordinate Ni⁰ N-heterocyclic carbene species [Ni(NHC)₂] (NHC=IiPr₂, IMe₄, IEt₂Me₂) affords a series of mononuclear, terminal phosphido nickel complexes. Structural characterisation of nine of these compounds shows that they have unusual trans [H−Ni−PR₂] or novel trans [R₂P−Ni−PR₂] geometries. The bis-phosphido complexes are more accessible when smaller NHCs (IMe₄>IEt₂Me₂>IiPr₂) and phosphines are employed. P−P activation of the diphosphines R₂P−PR₂ (R₂=Ph₂, PhMe) provides an alternative route to some of the [Ni(NHC)₂(PR₂)₂] complexes. DFT calculations capture these trends with P−H bond activation proceeding from unconventional phosphine adducts in which the H substituent bridges the Ni−P bond. P−P bond activation from [Ni(NHC)₂(Ph₂P−PPh₂)] adducts proceeds with computed barriers below 10 kcal mol⁻¹. The ability of the [Ni(NHC)₂] moiety to afford isolable terminal phosphido products reflects the stability of the Ni−NHC bond that prevents ligand dissociation and onward reaction.