Crystal structure of [CoEn3]2(W7O24)·6H2O

Crystal structure of a complex salt [CoEn₃]₂(W₇O₂₄)·6H₂O is determined by X-ray crystallography. Powder X-ray diffraction is applied for the phase identification of the products of thermal decomposition of the salt in the helium atmosphere.     

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.     

Single-molecule magnetism behavior of [Mn12O12(O2CR)16(H2O)4]2− salts

(PPh₄)₂[Mn₁₂O₁₂(O₂CCHCl₂)₁₆(H₂O)₄] (3) has been prepared by the two-electron reduction of [Mn₁₂O₁₂(O₂CCHCl₂)₁₆(H₂O)₄] (2) using iodide. Crystallization from CH₂Cl₂/hexanes yields a mixture of two crystal forms, 3·4CH₂Cl₂·H₂O (3a) and 36CH₂Cl₂ (3b), which are triclinic and monoclinic, respectively. They are both trapped valence 2Mn(II), 6Mn(III), 4Mn(IV). DC magnetization data for dried, unsolvated 3 in 1.80–4.00 K and 10–70 kG ranges were fit to give S=10, D=−0.28 cm⁻¹, g=2.00. Frequency-dependent out-of-phase (χ″_M) signals in AC susceptibility studies on crystalline sample of 3a and 3b combined with DC relaxation decay data were fit to the Arrhenius equation to give an effective energy barrier of U_eff=18.5 and 30.3 K, respectively. Magnetization vs. DC field sweeps on single crystals of 3a and 3b gave hysteresis loops containing steps due to quantum tunneling of magnetization (QTM). The step separations yielded ∣D∣/g values of 0.087 and 0.14 cm⁻¹, and consequently U=20 and 39 K (for g=2) for 3a and 3b, respectively, suggesting that the differences in U_eff are primarily caused by changes to D. This work demonstrates the sensitivity of the magnetic properties of [Mn₁₂]²⁻ single-molecule magnets to subtle differences in their environment.     

Crystal structure of [Co(NH3)5Cl]2(W10O32)·4H2O

By single crystal X-ray diffraction the crystal structure of the complex salt [Co(NH₃)₅Cl]₂(W₁₀O₃₂)·4H₂O is determined and the IR spectrum is interpreted. The crystal chemical analysis of the structure of complex cations and decatungstate anions and their packing in the structure is performed.     

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.     

The crystal structures of two Heteropolytungstate salts containing anions derived from α-octadecatungstodiphosphate(6-): (NH4)10[α2-P2W17O61]·8H2O and (ME2NH2)8[α2-P2Co(H2O)W17O61]·11H2O

The anions in (NH₄)₁₀[α₁-P₂W₁₇O₆₁]·8H₂O (I) and (Me₂NH₂)₈[α₂-P₂Co (H₂O)W₁₇O₆₁]·11H₂O (II) both have the [α-P₂W₁₈O₆₂]⁶⁻ structure with one “cap” W atom and its terminal oxygen atom missing (I), and a Co(H₂O)²⁺ group in place of one “cap” W atom and its terminal oxygen (II). Both anions have approximate mirror symmetry but are disordered in the crystal; inI the anion lies on a crystal inversion centre in two equally-weighted orientations, and in_II the Co atom appears as two Co_0.5W_0.5 composite atoms on either side of a crystallographic mirror plane. Crystal data include [diffractometer, Mo radiation, and ¦F¦>/3σ(F)]:I, Cmca, a = 18.080(8), b = 17.945(7), c = 21.546(8)Å, Z = 4, R = 0.067 for 1384 data;II, Pnam, a = 28.052(11), b = 15.069(12), c = 20.638(17)Å, Z = 4, R = 0.069 for 3057 data.     

Regioselective hydrogen-deuterium exchange in the [B10H10]2– anion. Syntheses of [1,10-B10H8D2]2– and [2,3,4,5,6,7,8,9-B10H2D8]2–

Decahydro-closo-decaborate anion, [B₁₀H₁₀]^2–, undergoes regioselective deuterio-exchange in methanol-d₄. Selectively deuterated derivatives [1,10-B₁₀H₈D₂]^2– and [2,3,4,5,6,7,8,9-B₁₀H₂D₈]^2– were synthesized.     

Vibrational spectra and structure of cesium salts of icosahedral monocarba-closo-dodecarborate anion, [CB11H12]–, and its nido-derivative, [CB100H13]–

The Raman and IR spectra of the cesium salts of monocarbon carboranes, [closo-CB₁₁H₁₂]^– and [nido-CB₁₀H₁₃]^–, are reported and the assignment of the normal modes is given. Quantum-chemical calculations of the geometry of undistorted closo-anions B₁₂H₁₂ ^2– and CB₁₁H₁₂ ^– were carried out and normal coordinate analysis for the latter was performed. Structural parameters and spectral characteristics of isoelectronic closo-polyhedra [B₁₂H₁₂]^2–, [CB₁₁H₁₂]^–, and p-C₂B₁₀H₁₂ and those of the closo- and nido-structures were compared.     

Synthesis and crystal structure of the salt of the protonated thiamine cation with the palladium(II) tetrachloride anion [HTA]2[PdCl4]Cl2 · 2H2O

The reaction of thiamine chloride hydrochloride with a solution of palladium chloride in hydrochloric acid gave a protonated thiamine salt [HTA]₂[PdCl₄]Cl₂ · 2H₂O (I) (TA is 4-methyl-3-[(2??-methyl-4??-amino-3??,4??-dihydropyrimidinyl-5??)methyl]-5-(2-hydroxyethyl)thiazolium cation, C₁₂H₁₆N₃O₂S). The crystal structure of I was determined by X-ray diffraction. The crystals are triclinic: a = 11.459(8) ?, b = 12.239(8) ?, c = 6.910(1) ?, ?? = 103.24(3)°, ?? = 76.95(3)°, ?? = 106.04(3)°, Z = 2, space group P $\bar 1$ . The structural units of I are doubly charged [HTA]²⁺ cations, [PdCl₄]^2? and Cl^? anions, and crystallization water molecules combined by hydrogen bonds and electrostatic interactions. The planar thiazolium and pyrimidine rings are in the F conformation, ??_t = 1.0°, ??_p = ?86.6°, and the dihedral angle between the planes is 85.5°. The torsion angles of the hydroxyethyl group are as follows: C(9)C(10)C(11)O(1), 175.6°; S(1)C(9)C(10)C(11), 33.2°; it is involved in the hydrogen bond with the free Cl^? anion. The sulfur atom forms a short (3.052 ?) intermolecular S-Cl contact with the chlorine atom of the [PdCl₄]^2? anion, which forms supramolecular chains.     

Electronic structure of the lithium molecular anion,Li2−

The electronic structure of the ground and excited states of the Li₂⁻ anion has been studied using optimized CI wavefunctions. The low-lying ²Σ_g⁺ state is of the Feshbach type and exhibits a near-degeneracy between ²Σ_g⁺ (υ′ = 0) of Li₂⁻ and ¹Σ_g⁺ (υ″ = 6) of Li₂. In contrast with the H₂⁻ system, we find a rich spectrum of low-lying resonant states for Li₂⁻.     

Electrodeposition of films from the tetrameric complex anion [(HOAs)4Mo12O46]4−

Appropriate conditions were selected to favour the non-destructive electroreductive deposition of [(HOAs)₄Mo₁₂O₄₆]⁴⁻ on solid electrode surfaces. During the first several cyclic voltammetry runs on glassy carbon electrodes, the surface activity of this tetrameric complex anion was found to depend on the nature of the supporting electrolyte anion. Cyclic voltammetry, electrochemical quartz crystal microbalance (EQCM) and atomic force microscopy (AFM) results converge to indicate that stable and porous films are formed, which should be suitable for electrocatalysis studies on a molecular basis.     

Crystal structure of a novel complex [Co(3,3′-bpbc)(H2O)3]·H2O

A novel coordination polymer constructed with [Co(3,3′-bpbc)(H₂O)₃]·H₂O(I) (3,3′-bpbc = 2,2′-bipyridine-3,3′-dicarboxylic acid) is successfully synthesized at room temperature and characterized by elemental analysis and IR spectra. The crystal structure of the complex is determined by single crystal X-ray diffraction. The unit cell parameters for complex I are: a = 9.9606(11) Å, b = 9.2552(10) Å, c = 16.0258(17) Å, β = 96.731(0)°, V = 1467.2(3) ų, Z = 4, space group P2(1)/n. In the crystal, the cobalt(II) ion adopts a hexa-coordinate environment, and the structure units aggregate together to give birth to infinite 1D chains. The 2D and 3D framework is constructed via intermolecular hydrogen bonds.     

Hydrothermal synthesis and characterization of two new arsenic–vanadate compounds with the same cluster anion [As8V14O42(H2O)]4−

Two new arsenic–vanadate compounds [Co(C₄H₁₃N₃)₂]₂[As₈V₁₄O₄₂(H₂O)]?·?3.5H₂O (1) and (C₂N₂H₉)₂(C₂N₂H₁₀)[As₈V₁₄O₄₂(H₂O)]?·?2.33H₂O (2) have been hydrothermally synthesized and characterized by X-ray single crystal diffraction, IR spectra and thermogravimetric analysis. Compound 1 crystallizes in the monoclinic space group P ₂(1)/c, a?=?24.649(9)?Å, b?=?13.364(5)?Å, c?=?22.463(8)?Å, β?=?104.008(5)°, V?=?7180(5)?ų, Z?=?4, R ₁?=?0.0787, and wR ₂?=?0.1859. Compound 2 crystallizes in rhombohedral system with space group R3c, a?=?b?=?c?=?22.2405(5)?Å, α?=?β?=?γ?=?110.4030(10)°, V?=?8163.4(3)?ų, Z?=?6, R ₁?=?0.0341 and wR ₂?=?0.0941. The structural analyses show that both compounds have the same discrete cluster anion [As₈V₁₄O₄₂(H₂O)]^4?. Moreover, in 1, the polyanions are connected through van der Waals forces to generate soft channels that are filled by [Co(C₄H₁₃N₃)₂]²⁺ cations and water. In 2, water and organic molecules link cluster anions to create the supramolecular assembly through hydrogen bonding.     

Synthesis and Crystal Structure of the Polyoxometalatebased Complex [Mn（DMSO）5H2O]2SiMo12O40

1 INTRODUCTION The design and assembly of organic-inorganic solid-state materials with active physical properties, such as materials with electrical, magnetic and opti- cal properties, has become a focus of a great deal of interest in recent years[1, 2].…     

Coordination interactions in the crystalline lattice of alkaline ions with the polyoxometalate [V12B18O60H6]10− ligand

In the present work, the synthesis and structural characterization of two new polyoxovanadoborate (BVO) frameworks, based on the [V₁₂B₁₈O₆₀H₆]^10? polyanion, are reported, K(H₃O)(enH₂)₄[V₁₂B₁₈O₆₀H₆]·9.60H₂O (1) and Li₈(NH₄)₂[V₁₂B₁₈O₆₀H₆]·8.02H₂O (2). Both compounds are obtained in a mixed valence ratio of 10V^IV/2V^V. Framework 1 is characterized by potassium ions coordinated by the BVO cluster and ethylenediammonium and hydronium ions as charge-compensating agents. In framework 2, the BVO clusters are coordinating lithium ions and the charge is compensated by ammonium ions. Using the SHAPE 2.1 program, it was possible to calculate the best geometry for the existing lithium and potassium ions. For 2, the lithium ions are five-coordinate, best described by a square pyramid (SPY-5), while the coordination sphere around the potassium ions in 1 are six-coordinate. For 1, the coordination sphere of the existing potassium ions in the framework can be described as trigonal prism (TPR-6). Calculations were also done for a previously reported cluster [Na₁₀[(H₂O)V₁₂B₁₈O₆₀H₆]·18H₂O] (3), in which the sodium ions are six-coordinate but in two different geometries, these being octahedral and TPR-6. The influence of the interactions of the alkali ions with the [V₁₂B₁₈O₆₀H₆]^10? polyanion, on the vanadate and borate absorption bands observed in the infrared spectra, is discussed.     

Synthesis and Crystal Structure of Two Decavanadates Cluster Metal Complexes: [Co(H2O)6]2[H2V10O28]·6H2O and (NH4)2[Ca(H2O)7]2[V10O28]

Two new decavanadate metal complexes, [Co(H₂O)₆]₂[H₂V₁₀O₂₈]·6H₂O (1) and (NH₄)₂[Ca(H₂O)₇]₂[V₁₀O₂₈] (2), have been synthesized under hydrothermal condition by using chlorhydric acid as the initiator at 120 °C. The aqueous NaVO₃ solution with an aqueous solution of CoCl₂·6H₂O were used for generating 1 and aqueous CaCl₂·2H₂O and NH₄VO₃ solution were employed for creating 2. Compound 1 consisted of discrete hexa-aqua-cobalt [Co(H₂O)₆]²⁺ cations, [H₂V₁₀O₂₈]⁴⁻ anions and non-coordination water molecules. Compound 2 were composed of hepta-aqua-calcium [Ca(H₂O)₇]²⁺ cations, ammonium NH₄ ⁺ and [V₁₀O₂₈]⁶⁻ anion. For compound 2, the distorted pentagonal bipyramid [Ca(H₂O)₇]²⁺ is uncommon. In the crystal lattice, hydrogen bonds played an important role on connecting cations, anions and non-coordinated water molecules to form the three-dimensional network.     

Synthesis and structure of new thiourea-containing Cobalt(III) dioximates with the [TiF6]2− anion

The new Co(III) dioximates [Co(DH₂)(D)(Thio)₂]₂[TiF₆] ·2DMF (I), [Co(NioxH)₂(Thio)₂]₂[TiF₆] · 2.25H₂O (II), and [Co(DpgH)₂(Thio)₂]₂[TiF₆] · 4DMF · 1.5H₂O (III) have been synthesized and studied (DH₂ and D are, respectively, the dimethylglyoxime molecule and doubly charged anion; NioxH and DpgH are singly charged anions of 1,2-cyclohexanedione dioxime and diphenylglyoxime, respectively; Thio is thiourea; DMF is dimethylformamide). The composition and structure of the complexes have been studies by IR, UV, and NMR spectroscopy. The crystal structures have been determined by X-ray crystallography. The hydrogen bonds in the structures are formed by fluorine atoms of the [TiF₆]^2? anion with Co(III) complex cations and solvent molecules of crystallization. The amino groups of coordinated thiourea molecules are also involved in the hydrogen bond system, which is responsible for their different arrangement with respect to the equatorial planes of the Co(III) complex cations.