超分子化合物[C6H11NH3]6[P2Mo18O62]·4H2O的水热法合成及结构

超分子化合物[C6H11NH3]6[P2Mo18O62]·4H2O的水热法合成及结构;Wells-Dawson结构;杂多化合物     

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.     

Structural and Physicochemical Studies of [4-ClC6H4CH2NH3]4Li2P6O18·4H2O

The crystal structure of a new organic cation cyclohexaphosphate, [4-ClC ₆ H ₄ CH ₂ NH ₃ ] ₄ Li ₂ P ₆ O ₁₈ .4H ₂ O, is reported. It crystallizes in the triclinic system (space group P-1) with the following unit-cell parameters: a = 9.628(8), b = 12.801(9), c = 19.528(6) Å, α = 78.60(4)°, β = 83.00(5)°, β = 89.98(4)°, Z = 2, and V = 2341(3)Å ³ . The structure has been solved using direct methods and refined by least-squares analysis [R ₁ = 0.043, wR ₂ = 0.108]. The structure can be described as infinite anionic layers with composition of [Li ₂ (P ₆ O ₁₈ )(H ₂ O) ₄ ] ^{4 ?} and parallel to the ac plane. The organic groups are located in the accessible voids. The molecules are stabilized by O─H…O and N─H…O types of intermolecular hydrogen bonds in the unit cell in addition to Van der Waals forces.     

Synthesis and Characterization of a New Cyclotriphosphate [C8H 11 NH 3 ] 3 P 3 O 9 ·3H 2 O

Among the various categories of phosphates, the number of organic cation cyclotriphosphates remains limited. In this work, we report the chemical preparation, crystal structure, thermal analysis, and spectroscopic investigations of a new cyclotriphosphate [C₈H₁₁NH₃]₃P₃O₉·3H₂O. It is characterized by X-ray diffraction, infrared spectroscopy, nuclear magnetic resonance, and thermal analysis. This compound is a triclinic P unit cell with the following parameters: a = 13.949(4), b = 9.867(3), c = 14.180(2) Å, α = 92.22(2), β = 119.27(2), γ = 85.10(10)°, V = 1696.1(8) Å ³ , and Z = 2. Its structure has been determined and refined to R = 0.041 and R_w = 0.062, using 4527 independent reflections. The atomic arrangement can be described by corrugated thick layers built by [P₃O₉]^3- anions, ammonium groups, and water molecules. The organic entities are located between these layers. H-bonds connecting the different species play an important role in the tridimensionnal network cohesion. This compound is also characterized by infrared spectroscopy, nuclear magnetic resonance, and thermal analysis.     

Syntheses, Crystal Structures and Characterization of Two Zeotype Crystals of K4[Cr3O(H2O)3(OOCH)6]2[P2W18O62] ·9.5H2O and K4[Cr3O(H2O)3(OOCH)6[H3P2W17Co(H2O)O61]·20H2O

Two novel zeotype crystals, K4[Cr3O(H2O)3(OOCH)6]2[P2W18O62]·9.5H2O(1) and K4 [Cr3O(H2O)3·X-ray single crystal diffraction. Crystal data: C12H43O103.5K4Cr6P2W18(1), hexagonal P6(3)/m, a=1.5895(2)nm, b=1.5895(2) nm, c=2.1620(4) nm, α=90°, β=90°, γ =120°, V=4.7305(13) nm3, Z=2,R1 =0. 0726, wR2=0. 1542; C6H57O98K4Cr3CoP2W17(2), hexagonal P6(3)/mmc, a=1. 61328 (3) nm, b=1.61328(3) nm, c=2. 06613 (9) nm, α=90°,β=90°, γ=120°, V=4. 6570(2) nm3, Z=2, R1=0. 0377,wR2 =0.1070. These crystals were characterized using elemental analysis, IR, TG-DTA, and XRD. It was found that the polyoxometalate anions maintained Wells-Dawson structure for crystal 1 and lacunary Wells-Dawson structure for crystal 2. Thermal analysis showed that crystal 1 lost the water of crystallization at 132 ℃, whereas crystal 2 lost the water of crystallization at 100 ℃. Crystal 1 could reversibly desorb and adsorb water molecules and its crystal structure could be restored after re-adsorbing the water molecules. It was also found from the XRD patterns that the void size of crystal 2 is smaller compared with that of crystal 1, which is attributed to the higher anion charges.     

Synthesis and Structural Characterization of a Polyoxomolybdate HNa7[Mo36O112(H2O)16]·47H2O

A new polyoxomolybdate complex HNa7[Mo36O112(H2O)16]·47H2O 1 has been prepared in the beaker solution and characterized by single-crystal X-ray diffraction and elemental analyses. Crystal data: H127Mo36Na7O175, Mr = 6542.79, monoclinic, C2/c, a = 40.891(6), b =17.900(3), c = 25.580(4) (A), β = 125.673(2)°, V = 15210(4)(A)3, Z = 4, Dc = 2.857 g/cm3, F(000) =12464, μ = 3.013 mm-1, R = 0.0633 and wR = 0.1654 (I＞ 2σ(Ⅰ)). With the bridging sodium cations,the [Mo36O112(H2O)16]8- units in compound 1 are linked to form a one-dimensional structure, on the basis of which a three-dimensional architecture is further constructed via other sodium cations and complicated hydrogen bonds.     

Synthesis and physicochemical study of diazabicycloundecene hexamolybdochromate [C9H16N2]H3[CrMo6O18(OH)6] · 2H2O

Quinazoline hexamolybdochromate [C₉H₁₆N₂]H₃[CrMo₆O₁₈(OH)₆] · 2H₂O has been synthesized and studied by mass spectroscopy, X-ray powder diffraction, thermogravimetry, and IR and NMR spectroscopy. The compound crystallizes in triclinic system with the unit cell parameters a = 15.06 Å, b = 13.08 Å, c = 8.17 Å, α = 59.85°, β = 123.15°, γ = 107.01°, V = 1165.62 ų, ρ_pycn = 3.58 g/cm³, and Z = 2.     

NMR studies on the chemical constitution of the chain trimolybdate anion [H2Mo3O11]n2−

The NMR method has been employed for investigation of the fibrillar lithium trimolybdate. The results indicate that the ratio of the number of OH groups to that of water molecules in the coordination sphere of the central molybdenum atom is dependent on the temperature.     

K4H2[PMo9V3O40]·10H2O的合成及其晶体结构

采用低温技术,用X射线单晶衍射法测定了标题化合物的结构。晶体属P4/mnc空间群,=12.515(3),c=17.636(7)A,Z=2.用788个独立可观测反射精修所有结构参数得R=0.061.钼钒磷杂多酸阴离子中,PO4四面体是无序的,P-O键长1.54A.M(Mo,V)是6配位,M-O键长1.62-2.48A,K是7配位,K-O键长2.84-3.10A。     

K4H2[PMo9V3O40]·10H2O的合成及其晶体结构

采用低温技术,用 X 射线单晶衍射法测定了标题化合物的结构.晶体属 P4/mnc 空间群,a=12.515(3),c=17.636(7),Z=2.用788个独立可观测反射精修所有结构参数得 R=0.061.钼钒磷杂多酸阴离子中,PO_4四面体是无序的,P—O 键长1.54.M(Mo,V)是6配位,M—O 键长1.62—2.48.K 是7配位,K—O 键长2.84—3.10.     

Thermal transformations of α-H6P2Mo18O62·nH2O heteropolyacid

According to the ³¹P NMR spectroscopy, heteropolyacid (HPA) H₆P₂Mo₁₈O₆₂·nH₂O (P₂Mo₁₈), -isomer of the Dawson structure, transforms upon heating above 80 °C partially (up to 30%) to -isomer, in which both polar groups Mo₃O₁₃ of the heteropolyanion are turned by 60° around the N₃ axis, and partially to -isomer in which only one group is turned. The - and -isomers of P₂Mo₁₈ have been found for the first time. Their transformation into the -isomer occurs upon rehydration in one week in air and in 1 h in an aqueous solution. HPA P₂Mo₁₈ decomposes on heating up to 350 °C to HPA H₃PMo₁₂O₄₀ (PMo₁₂) and a previously unknown phase of the HPMo₆I₂₁ composition, which in its turn decomposes at 375 °C to molybdenyl phosphates and IiI₃. The PMo₁₂ decomposition occurs via two routes to form the same products at temperatures of 400 and 450 °C with corresponding exotherms of IiI₃ crystallization.     

Determination of the protonation state of [H3PW11O39]4− and the stability constant of [Ag(H2O)(H3PW11O39)]3− in aqueous solution

By employing elemental analysis, ³¹P NMR, pH, and conductivity measurements, the protonated state of lacunary heteropolyoxotungstophosphates in aqueous solution, {PW₁₁O₃₉}, is determined to be [H₃PW₁₁O₃₉]^4?. Using it as ligand, a complex of [Ag(H₂O)(H₃PW₁₁O₃₉)]^3? is formed. An electrochemical cell is designed as follows: (?) Hg, Hg₂Cl₂ [Ag(H₂O)(H₃PW₁₁O₃₉)]^3? (aq) | Ag(s) (+) (salt bridge is saturated KNO₃ solution). By measuring the electromotive force of the cell, the stability constant of [Ag(H₂O)(H₃PW₁₁O₃₉)]^3? in aqueous solution is determined to be 4.34 × 10³ (25 °C).     

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.     

Synthesis and Structural Characterization of [Mn（sapn）（H2O）2]Br

1 INTRODUCTION Many of the recent advances in the coordination chemistry of manganese have been driven by the involvement of the manganese in several biological redox-active systems[1,2], of which the most important is the oxygen-evolving complex (EOC) of photosystem II (PS II) in green plants [3]. Since the preparations and structural characterizations of the complexes containing N,O-donor ligands have been studied extensively as simple active-site models for the photosystem II[4,5]…     

Thermogravimetric analysis of the copper silicate mineral dioptase Cu6[Si6O18]·6H2O

There have been a few studies on the thermal decomposition of dioptase Cu₆[Si₆O₁₈]·6H₂O. The results of these analyses are somewhat conflicting and the conclusions vary among these thermo-analytical studies. The objective of this research is to report the thermal analysis of dioptase from different origins and to show the mechanism of decomposition. Thermal decomposition occurs over a very wide temperature range from around 400 to 730 °C with the loss of water. Two additional mass loss steps are observed at around 793 and 835 °C with loss of oxygen. The infrared spectra of dioptase in the hydroxyl stretching region enables the hydrogen bond distances of water molecules in the dioptase structure to be calculated. The large variation in the hydrogen bond distances offers an explanation as to why the decomposition of dioptase with loss of water occurs over such a wide temperature range.     

Specific nonbonding interactions in the structure of (N2H5)2[Mo3S7I6]·1.5H2O

The crystal structure of (N₂H₅)₂[Mo₃S₇I₆]· 1.5H₂O is investigated;triclinic crystals, a-10.029(2), b = 10.258(3), c =14.152(2) å, a =109.21(2), Β =106.14(1), γ =98.97(2)?, V _cell =1270.6(5) å ³, space group P1, Z =2, d _calc =3.572 g/cm ³, CAD-4 diffractometer, λMoK_α, 2θ_max =50?, N _tot =4118, R(F) = 0.0554, wR(F²) = 0.1365 for 3057 F_hkl 4Σ(F). The cluster onions are united into centrosymmetric dimers with distances 3S_ax...I 3.324(5)-3.473(4) å. The dimers, in turn, form a three-dimensional framework with cations and solvate water molecules in the cavities due to additional contacts S_eq...I and S_ax...I 3.624(4)-3.785(4) å. The hydrogen bonds formed in the structure are N(N₂H₅)...O(H₂O) and N(N₂H₅)...I 2.78(4)-2.96(8), 3.64(3)-3.75(3) å. The nonbonding interactions completely determine the crystal structure.     

NH2SO3H and H6P2W18O62 · 18H2O-Catalyzed,Three-Component,One-Pot Synthesis of Benzo[c]acridine Derivatives

We report here two simple methods for the synthesis of benzo[c]acridine derivatives from three-component, one-pot condensation of 1-naphthylamine, dimedone, and a variety of substituted aldehydes in the presence of a catalytic amount of NH₂SO₃H or H₆P₂W₁₈O₆₂ · 18H₂O under solvent-free conditions at 120 °C or in refluxing ethanol.     

Syntheses and Crystal Structures of (H3O)(C3H5N2)[Mn(OH)6 Mo6O18]·3.5H2O and (H3O)3[Co(OH)6Mo6O18]·7H2O

The crystals of the title compounds (H3O)(C3H5N2)[Mn(OH)6Mo6O18]·3.5H2O 1 and (H3O)3[Co(OH)6Mo6O18]·7H2O 2 have been prepared and structurally determined by X-ray single-crystal diffraction. Compound 1 crystallizes in monoclinic, space group C2/c with a = 21.5018(9), b = 10.9331(5), c = 11.8667(5)A,β = 95.3570(10)o, V = 2777.5(2)A3, Z = 4, Dc = 2.802 g/cm3, Mr = 1171.80,μ(MoKα) = 3.173 mm-1, F(000) = 223, the final R = 0.0458 and wR = 0.1041 for 2093 observed reflections (I>2σ(I)); Compound 2 crystallizes in monoclinic, space group P21/c with a = 11.4042(12), b = 10.9481(11), c = 11.6722(12)A, β= 99.948(2)o, V = 1435.4(3)A3, Z = 2, Dc = 2.794 g/cm3, Mr = 1207.80,μ(MoKα) = 3.223 mm-1, F(000) = 1160, the final R = 0.0544 and wR = 0.1066 for 1906 observed reflections (I > 2σ(I)). Both compounds 1 and 2 adopt the Anderson structure, in which the anion is of centrosymmetry and formed by six octahedral edge-sharing MoO6 units surrounding the central MO6 (M = Mn or Co) octahedron.     

Syntheses,structures, and properties of two new hybrid Dawson-based polyoxotungstates [Mn(2,2′-bipy)3]H2 [Mn(2,2′-bipy)2][P2W18O62] and [Co(H2biim)3)]2H2[P2W18O62] · 8H2O

Two new hybrid Dawson-based polyoxotungstates, [Mn(2,2′-bipy)₃]H₂[Mn(2,2′-bipy)₂][P₂W₁₈O₆₂] (1) and [Co(H₂biim)₃)]₂H₂[P₂W₁₈O₆₂] · 8H₂O (2) (2,2′-bipy = 2,2′-bipyridine, H₂biim = 2,2′-biimdazole), have been prepared under hydrothermal conditions and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra, thermogravimetric analyses (TGA), X-ray photoelectron spectroscopy (XPS), and photoluminescence spectra. Compound 1 is a 1-D zigzag chain constructed from alternate Dawson-type heteropolyanions [α-P₂W₁₈O₆₂]^6? and metal coordination cations [Mn(2,2′-bipy)₂]²⁺, in which the 1-D chains are extended into a 3-D framework through C–H ··· π and π–π stacking interactions. Compound 2 is a discrete structure consisting of [α-P₂W₁₈O₆₂]^6? and two [Co(H₂biim)₃)]²⁺ cations, forming a 3-D supramolecular framework via N–H ··· O hydrogen bonds and C–H ··· π interactions. Photoluminescence properties of 1 and 2 have been investigated at room temperature.