Crystal structure and nonlinear optical properties of the K2UO2(SO4)2 · 2H2O compound at 293 K

Single crystals of potassium uranyl sulfate are grown, and their atomic structure is determined using X-ray diffraction analysis. The compound crystallizes in the orthorhombic crystal system with space group Pna2₁ [a = 13.773(4) Å, b = 7.288(2) Å, c = 11.556(4) Å, R ₁ = 0.033, wR ₂ = 0.0892 for 2630 reflections with I > 2σ(I)]. The crystal structure of the K₂UO₂(SO₄)₂ · 2H₂O compound is built up of two-dimensional infinite, negatively charged layers of the composition [UO₂(SO₄)₂·H₂O] _2∞ ^δ? ], which are linked together through the K⁺ ions. The specific features of the atomic arrangement in the structure of this compound are analyzed, and the second harmonic generation of laser radiation is investigated.     

Crystal and molecular structure of 7-hydroxyflavone monohydrate, C14H10O3·H2O

The X-ray crystal structure of 7-hydroxyflavone monohydrate, C₁₄H₁₀O₃ · H₂O, is determined. The compound crystallizes in the monoclinic space group, P2₁/n with a = 3.801(3), b = 19.665(4), c = 16. 039(6), = 93.69(3)°, and = 0.68 mm^–1 for Z = 4. The phenyl ring of the flavone moiety is rotated 18.6(1)° out of the penzopyran plane, which is a typical value for flavones. In the crystal lattice, there are wide channels which are lined mainly by C–H groups. The water molecules enclosed in these channels are severely disordered.     

Crystal structure and hydrogen-bonding system of cholic acid hemihydrate,C24H40O5·1/2H2O

Crystals of the hemihydrate of this bile acid are hexagonal, space groupP6₅22, a=b=13.736(8)Å,c=85.06(6)Å,V=13,899ų. The asymmetric unit contains two independent steroid molecules and one water molecule, the latter disordered over two nonequivalent positions.Z=12[2(C₂₄H₄₀O₅)·1(H₂O)],F(000)=5496. Structure solution by direct methods; refinement by least-squares, toR=0.072. The complex hydrogen-bond system comprises: (a) three standard ordered O-HO hydrogen-bonds; (b) what is probably a symmetrically hydrogen-bonded carboxylic acid dimer, with a twofold rotation axisin the plane of the two carboxyl groups; (c) helical hydrogen-bonding chains about each 6₅ axis, disordered over four possible arrangements. In these helical chains, the six independent hydrogen-bonds can as a group be in either of two systems of nearly equivalent flip-flop arrangements: O-HO OH-O. Each helical system includes water, which can occupy either of two sites; thus, there is further disorder involving two sets of nonequivalent hydrogen-bonds with water as donor and acceptor. Many aggregation features here differ markedly from those in the crystal structures of either anhydrous cholic acid or cholic acid monohydrate.     

Synthesis, crystal structure, and thermal property of a novel supramolecular assembly: (NH4)2(C8H10N4O2)4 [H4V10O28]·2H2O, constructed from decavanadate and caffeine

A novel 3D supramolecular assembly constructed from decavanadate and caffeine building blocks, (NH₄)₂(C₈H₁₀N₄O₂)₄[H₄V₁₀O₂₈]·2H₂O (1), has been synthesized in aqueous solution and characterized by elemental analysis, IR, ¹H NMR, ⁵¹V NMR, TG-DTA, and single crystal X-Ray diffraction. The compound 1 crystallizes in monoclinic system, space groupP2 ₁/n, a = 15.801(1) Å, b = 12.914(1) Å, c = 15.913(2) Å, = 113.55°,V = 2976.4 (5)ų, Z = 2, R = 0.0498 with 6818 reflections. Water molecules, ammonium ions, and caffeine act as cement linking the polyanions into 1D chain along the c-axis by hydrogen bonding. In compound 1, extensive hydrogen-bond contacts and strong – interactions lead to an ordered 3D supramolecular framework. TG-DTA curves indicate that the weight loss of the complex can be divided into three stages.     

Hydrothermal crystallization and X-ray structure determination of a new decavanadate with mixed cations [Mn(H2O)6]2[N(CH3)4]2[V10O28]·2H2O

A new decavanadate with mixed cations, [Mn(H₂O)₆]₂[N(CH₃)₄]₂[V₁₀O₂₈]·2H₂O (1), was crystallized from a hydrothermal reaction between MnCO₃ and V₂O₅ in the presence of N(CH₃)₄Br at 100°C. The structure of 1, as determined by x-ray single crystal analysis, consists of cations and anions of hexa-aqua manganese [Mn(H₂O)₆]²⁺, tetramethyl ammonium [N(CH₃)₄]⁺ and decavanadate [V₁₀O₂₈]^6–. The extended H-bonding between the [Mn(H₂O)₆]²⁺ and [V₁₀O₂₈]^6– ions gives rise to a pseudo- two-dimensional network in the crystal lattice x-ray crystallographic data for 1: monoclinic P2₁/n, a = 9.1499(5), b = 12.8725(7), c = 18.625(1) Å, = 92.252(1)°, V = 2192.0(2) ų, MZ = 2, and D _calcd = 2.22 g cm^–3.     

Structure of V2O5–P2O5 glasses by X-ray and neutron diffraction

The atomic structures of two V₂O₅–P₂O₅ glasses and vitreous (v-) V₂O₅ were investigated by X-ray and neutron diffraction. The V=O double bond is a common characteristic of the VO_n units that constitute the structures of the glasses. VO₅ square pyramids with elongated bonds of ~ 0.190 nm to the pyramidal base are found for the 50V₂O₅–50P₂O₅ glass. These weaker V–O bonds are balanced in V–O–P bridges by overbonded P–O bonds. The V^(IV) sites, which account for 19.7% and 35.2% of the total V sites in the 73V₂O₅–27P₂O₅ and 50V₂O₅–50P₂O₅ glasses, respectively, form similar pyramids in agreement with the structure of crystalline (VO)₂P₂O₇. The short-range structure of v-V₂O₅ and the 73V₂O₅-27P₂O₅ glass is formed of mixtures of VO₅ and VO₄ pyramids. A significant amount of V···O distances > 0.22 nm found for all glasses belong either to linkages V=O···V or to three-coordinated O sites.     

Synthesis and crystal structure of [Ni(H2O)6](C19H17O9S)2·2H2O

A water soluble flavonoid sulfate, [Ni(H₂O)₆](C₁₉H₁₇O₉S)₂·2H₂O was synthesized and its structure was determined by single-crystal X-ray diffraction analysis. The crystal of it belongs to triclinic crystal system, space group P–1. The results show that the title compound consists of [Ni(H₂O)₆]²⁺, C₁₉H₁₇O₆SO₃ ⁻ and H₂O. Ni(II) is located on the symmetry center and octahedrally coordinated by six water molecules. A variety of hydrogen bonds among [Ni(H₂O)₆]²⁺, C₁₉H₁₇O₆SO₃ ⁻ and the lattice water molecules build a hydrophilic region. Aromatic π–π stacking interactions assemble isoflavone skeletons into a column and the columns form a hydrophobic region of the title compound. The sulfo-groups bridge the hydrophilic regions and the hydrophobic regions as well as the inorganic components and organic components. Hydrogen bonds, stacking interactions and the electrostatic interactions between cation [Ni(H₂O)₆]²⁺ and anion sulfonate C₁₉H₁₇O₆SO₃ ⁻ lead the moieties to a three-dimensional structure.     

Synthesis and crystal structure of a new lithium cyclohexaphosphate hydrate: Li6P6O18·10H2O

The synthesis and crystal structure of a novel hydrate of lithium cyclohexaphosphate are reported. Li₆P₆O₁₈·10H₂O crystallizes in the space group C2/c with a = 15.113(5), b = 12.006(2), c = 15.892(2) Å, = 122.85(2)°, and Z = 4. The structure consists of P₆O₁₈ ring layers stacked along the c direction in between which are located the lithiumions and water molecules. Two LiO₄ tetrahedra share common edges with LiO₅ pseudosquare pyramids to form two independant Li₃O₉ units. About 50% of the water molecules have fractional occupancy rates and form fragments of molecules. A linear relationship is established between the relative cell volume V/Z and the hydration degree, n, for all the known hydrates: Li₆P₆O₁₈·nH₂O.     

Temperature-induced changes in the single-crystal structure of K9H7(SO4)8 · H2O

Interest in superprotonic crystals of M _m H _n (XO₄)_{(m + n)/2} is associated with the solution to the fundamental problem of modern condensed matter physics: investigations of structural phase transitions and the stabilization of phases with high proton conductivity with the aim of designing new functional materials. The available data suggest that changes in the physical properties in these crystals can occur through different structural mechanisms. To reveal the structural conditionality for anomalies in the physical properties, the crystals of K₉H₇(SO₄)₈ · H₂O were studied by X-ray diffraction in the temperature range of 25–463 K, and the crystal structure of the high-temperature phase was determined at 418 K (sp. gr. Pcan). The results of the study indicate that the occurrence of high conductivity in K₉H₇(SO₄)₈ · H₂O crystals at high temperatures is associated with the diffusion of water of crystallization, the hydrogen-bond network rearrangement, and the motion of K ions. The hydrogen-bond rearrangement and the hindered back diffusion of water to the crystal stabilize the high-temperature phase and ensure its supercooling to low temperatures.     

Interferometric study of the growth kinetics of K2Co(SO4)2 · 6H2O and K2Ni(SO4)2 · 6H2O crystals

Crystallography Reports - The growth kinetics of the (001) and (110) faces of K2Co(SO4)2 · 6H2O and K2Ni(SO4)2 · 6H2O crystals in the kinetic mode has been in situ investigated for the...     

Synthesis and structure of [Ca(triethyleneglycol)2](NO3)2·H2O

Crystallization of calcium nitrate from a toluene solution of triethyleneglycol (= 2,2-[1,2-ethanediylbis(oxy)]-bisethanol) resulted in the formation of the 1:2 solvate [Ca(triethyleneglycol)₂](NO₃)₂·H₂O. [Ca(C₆H₁₄O₄)₂](NO₃)₂·H₂O is monoclinic, P2₁/c, a = 15.775(1), b = 8.660(2), c = 16.342(1) Å, = 91.239(7)°, V = 2232.1(6) ų, Z = 4, and D _c = 1.429 g cm^–3. The eight-coordinate calcium has square antiprismatic geometry with two triethyleneglycol molecules straddling the metal center. The nitrate anions and water of crystallization are involved in hydrogen bonding with the alcoholic hydrogen atoms.     

Synthesis and structure of (H2O·HBF4)2(18-crown-6)

The title compound has been prepared by the addition of fluoroboric acid to 18-crown-6 in toluene. The compound crystallizes in the triclinic space group P¯1 witha=7.341(2),b=8.364(2),c=10.631(3)Å,=71.48(2),=67.91(2), =67.94(2)°, andD _c =1.44 g cm^–3 forZ=1. The final conventionalR value was 0.079 based on 1575 observed reflections. The molecule resides on a center of inversion. The (H₂O·HBF₄) moieties are best viewed as fluoroboric acid monohydrate molecules hydrogen bonded to the crown ether, one above and one below the plane of the crown. The FO(water) hydrogen bond separation is 2.474(5)Å, and the O(crown)O(water) separations are 2.834(5) and 2.841(6) Å. The oxygen atoms of the crown ether are planar to 0.23 Å.     

Low temperature phases of strontium nitroprusside tetrahydrate (Sr[Fe(CN)5NO]·4H2O). Refinement of the neutron structure at 60 K

The behavior of Sr[Fe(CN)₅NO]·4H₂O between room temperature and 77 K has been investigated by X-ray powder diffraction (XRD), differential thermal analysis (DTA), and infrared spectroscopy (IRS). DTA puts into evidence five phase transitions—at 152.7, 174.3, 183.0, 193.0, and 199.5 K—when temperature is increased very slowly. When decreasing the temperature, XRD detects a change of space group below 153 K—from C2/m to P2/m—already reported as a result of a neutron diffraction study performed at 130 K. The P2/m space group remains at least down to 60 K. The structure at this temperature (monoclinic, space group P2/m, Z = 4, a = 19.765(21) Å, b = 7.540(5) Å, c = 8.384(1) Å, β = 98.87(1)°, V = 1236(16) ų) has been refined to a final R factor 0.077 using 687 observed structure factors. Of the two series of IR spectra obtained when cooling the sample (first series) and when heating the previously cooled sample (second series), only a feature of the first series of spectra seems to be related with the transition observed at 153 K.     

Crystal structure of neptunium(V) sulfate hexahydrate, (NpO2)2SO4 · 6H2O

Single crystals of (NpO₂)₂SO₄ · 6H₂O are obtained, and their structure is determined. The structure is built of NpO ₂ ⁺ dioxo cations, SO ₄ ^2? anions, and molecules of coordination and crystallization water. The NpO ₂ ⁺ ions are linked into cationic ribbons stretched along the [001] direction. In the ribbons, neptunoyl ions of one type act as monodentate ligands, whereas neptunoyl ions of the other type coordinate the neighboring neptunoyl groups by two oxygen atoms. The Np(1) and Np(2) atoms have oxygen environments in the shape of a pentagonal bipyramid whose equatorial plane consists of oxygen atoms of the neighboring dioxo cations, sulfate ions, and water molecules. The sulfate ion acts as a bidentate ligand bridging the two neighboring atoms Np(1) and Np(2). Six water molecules are revealed in the structure; one of them is a crystallization water molecule. Hydrogen bonds link cationic ribbons into a three-dimensional network.     

Synthesis and crystal structure of a new bimetallic complex of diethylenetriamine pentaacetic acid: [YbAg2(dtpa)(H2O)]·3H2O

The reaction between Yb(III) nitrate, Ag(I) nitrate, and the diethylenetriamine pentaacetate (dtpa) ligand gives rise to a bimetallic complex. [YbAg₂(dtpa)(H₂O)]·3H₂O is triclinic, space group P-1, with a = 8.768 (3), b = 9.862 (2), c = 13.055 (2) Å, = 75.40 (1), = 83.00 (2) and = 87.46 (2)°. Each dtpa is coordinated to one ytterbium and six silver atoms. The resulting crystal structure can be described as 2D packing. In the layers, the ytterbium atoms are connected through [Ag(COO)]₂ dimers. Strong hydrogen bonds, involving the noncoordinated water molecules, ensure crystal cohesion.     

The crystal and molecular structure of 14-β-N-pentylaminomorphinone,C22H28N2O3

The crystal and molecular structure of 14--N-pentylaminomorphinone (14--N-PAM), C₂₂H₂₈N₂O₃, has been determined by analysis of single crystal X-ray diffraction data. The compound crystallized at room temperature in the orthorhombic system, space group P2₁2₁2₁ witha=12.4535(8),b=13.7855(8),c=11.710(1) Å,V _c =2010.3(2) ų,Z=4,D _x =1.22 gm/cm³,(Cu K)=6.58 cm^–1, andF(000)=792. The final refinement yieldedR=0.051,R _w =0.059 for 328 variables with 1133 unique observed reflections. The absolute configuration is established via the synthesis from thebaine by the noninvolvement of certain asymmetric centers. The molecule is found to have as its central structure a T shape similar to that found in morphine and codeine. The distinctive feature of the molecule is the 14--N-pentylamino lipophilic side chain. Molecular modeling studies on the alkylamino chain result in the identification of clusters of conformations based on energy and dihedral angle criteria. Selected conformations are compared to 19-propylthevinol (etorphine), another potent analgesic which contains a lipophilic hydroxyalkyl substituent at C19. The enhanced analgesic activity of 14--N-pentylaminomorphinone is postulated to arise from an overall morphine-like contact with the receptor augmented by the interaction of the aliphatic chain with a lipophilic receptor pocket.     

Metal-hydroxycarboxylate interactions: syntheses and structures of K2[VO2(C6H6O7)]2·4H2O and (NH4)2[VO2(C6H6O7)]2·2H2O

Potassium and ammonium dimeric (citrato)dioxovanadium(V) hydrate K₂[VO₂(H₂cit)]₂·4H₂O1 and (NH₄)₂[VO₂(H₂cit)]₂·2H₂O2 (H₄cit=citric acid) have been prepared and characterized by X-ray structure analyses. Vanadate1 crystallizes in the monoclinic space groupP2₁/n (No. 14) with unit cell parameters:a=9.304(2),b=11.756(2),c=11.911(2)Å, =111.72(3)°, andD _c=1.911 g/cm³,Z=2; Vanadate2 also crystallizes in the monoclinic space groupP2₁/n with unit cell parameters:a=9.719(2),b=11.111(3),c=11.294(2)Å, =109.03(2)°, andD _c=1.781 g/cm³,Z=2. Each dimer contains a centro-symmetric planar four-member V₂O₂ ring with two exocyclic citrate entities coordinated by the oxygen atoms of the hydroxy-and -carboxylate ligands, while the other two -carboxylate groups remain uncomplexed. Principal dimensions of the V–O bonds are 1.986(4)_av (hydroxy) and 1.980(3)Å(-carboxyl) for vanadate1, 1.988(2)_av (hydroxy) and 1.974(3)Å(-carboxyl) for vanadate2.     

Synthesis and crystal structure of hexaaquamagnesium hydrogen phosphododecatungstate tetrahydrate [Mg(H2O)6][HPW12O40]·4H2O

Crystals suitable for X-ray structure analysis were obtained after the slow evaporation of the reaction mixture containing equimolar quantities of magnesium chloride and dodecatungstophosphoric acid aqueous solution insuring pH of the solution between 1.0 and 1.2. This simple synthetic route yielded stability of Keggin anion and high quality [Mg(H₂O)₆][HPW₁₂O₄₀]·4H₂O single crystals. The obtained compound belongs to the group of heteropoly compounds and its structure is composed of Keggin [PW₁₂O₄₀]^3– anions, [Mg(H₂O)₆]²⁺ cations and lattice water molecules. Zigzag arrangement of Keggin anions along c-axis creates irregular channels occupied by [Mg(H₂O)₆]²⁺ cations and lattice H₂O molecules. The calculation of the total potential solvent volume indicated the presence of 4.1 lattice H₂O lattice molecules per formula unit, which is in agreement with the here presented structural model. The position of one lattice water molecule is well defined, while each of three other molecules is statistically distributed over two locations. Hydrogen bonds involve all coordinated and lattice H₂O molecules, as well as some oxygen atoms from the Keggin anion. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Molecular structure of [trans-FeCl2(imidazole)4]Cl·THF·H2O

The structure of [trans-FeCl₂(imidazole)₄]Cl has been determined as the THF/H₂O solvate. The Fe-Cl and Fe-N distances in the cation are shorter than analogous trans-FeCl₂(L)₄ compounds, concomitant with the decreased ionic radius of Fe³⁺ versus Fe²⁺. Crystal data: orthorhombic, Pnma, a = 8.456(2), b = 20.991(4), c = 13.288(3) Å, V = 2358.6(8), andZ = 4.