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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. 相似文献
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O. Amri S. Abid M. Rzaigui 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3):766-777
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. 相似文献
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M. L. Mrad C. Ben Nasr M. Rzaigui 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):2757-2769
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 Rw = 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. 相似文献
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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. 相似文献
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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. 相似文献
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S. Holguín Quiñones G. Z. Kaziev Yu. S. Vlasov A. V. Oreshkina O. A. Kirichenko A. M. Koroteev 《Russian Journal of Inorganic Chemistry》2014,59(5):469-471
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 Å3, ρpycn = 3.58 g/cm3, and Z = 2. 相似文献
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《Journal of Inorganic and Nuclear Chemistry》1978,40(1):49-51
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. 相似文献
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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. 相似文献
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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). 相似文献
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Hanbin Hu Yixin Yang Xiao Jiang Jiaxin Wang Dongwei Cao Lei He Wei Chen Prof. Dr. Yu-Fei Song 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(53):13367-13375
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. 相似文献
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Synthesis and Structural Characterization of [Mn(sapn)(H2O)2]Br 总被引:1,自引:0,他引:1
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]… 相似文献
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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. 相似文献
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A. V. Virovets M. N. Sokolov I. V. Kalinina N. V. Podberezskaya V. E. Fedorov 《Journal of Structural Chemistry》1999,40(1):46-50
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, λMoKα, 2θmax =50?, N tot =4118, R(F) = 0.0554, wR(F2) = 0.1365 for 3057 Fhkl 4Σ(F). The cluster onions are united into centrosymmetric dimers with distances 3Sax...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 Seq...I and Sax...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. 相似文献
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Majid M. Heravi Hamideh Alinejhad Fatemeh Derikvand Hossein A. Oskooie Bita Baghernejad Fatemeh F. Bamoharram 《合成通讯》2013,43(14):2033-2039
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. 相似文献
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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. 相似文献
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《Journal of Coordination Chemistry》2012,65(11):1844-1855
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. 相似文献