Structure Determination of a Complex Tubular Uranyl Phenylphosphonate, (UO(2))(3)(HO(3)PC(6)H(5))(2)(O(3)PC(6)H(5))(2).H(2)O, from Conventional X-ray Powder Diffraction Data

The three-dimensional structure of a complex tubular uranyl phosphonate, (UO(2))(3)(HO(3)PC(6)H(5))(2)(O(3)PC(6)H(5))(2).H(2)O, was determined ab initio from laboratory X-ray powder diffraction data and refined by the Rietveld method. The crystals belong to the space group P2(1)2(1)2(1), with a = 17.1966(2) ?, b = 7.2125(2) ?, c = 27.8282(4) ?, and Z = 4. The structure consists of three independent uranium atoms, among which two are seven-coordinated and the third is eight-coordinated. These metal atoms are connected by four different phosphonate groups to form a one-dimensional channel structure along the b axis. The phenyl groups are arranged on the outer periphery of the channels, and their stacking forces keep the channels intact in the lattice. The determination of this structure which contains 50 non-hydrogen atoms in the asymmetric unit, from conventional X-ray powder data, represents significant progress in the application of powder techniques to structure solution of complex inorganic compounds, including organometallic compounds.     

Synthesis and characterization of open-framework niobium silicates: Rb2(Nb2O4)(Si2O6).H2O and the dehydrated phase Rb2(Nb2O4)(Si2O6)

A new niobium(V) silicate, Rb(2)(Nb(2)O(4))(Si(2)O(6)).H(2)O, has been synthesized by a high-temperature, high-pressure hydrothermal method and characterized by single-crystal X-ray diffraction, thermogravimetric analysis, and solid-state NMR spectroscopy. It crystallizes in the tetragonal space group P4(3)22 (No. 95) with a = 7.3431(2) A, c = 38.911(3) A, and Z = 8. Its structure contains tetrameric units of the composition Nb(4)O(18), which share corners to form a layer of niobium oxide. The Nb-O layer is a slice of the pyrochlore structure. Neighboring Nb-O layers are linked by vierer single-ring silicates generating eight-ring and six-ring channels running parallel to <100> directions, in which the Rb(+) cations and water molecules reside. The tantalum analogue was prepared and characterized by powder X-ray diffraction. Upon heating to 500 degrees C, Rb(2)(Nb(2)O(4))(Si(2)O(6)).H(2)O loses lattice water molecules, while the framework structure is retained to give the anhydrous compound Rb(2)(Nb(2)O(4))(Si(2)O(6)), whose structure was also characterized by single-crystal X-ray diffraction. The dehydrated sample absorbs water reversibly, as indicated by powder X-ray diffraction. Rb(2)(Nb(2)O(4))(Si(2)O(6)) crystallizes in the tetragonal space group I4(1) (No. 80) with a = 10.2395(6) A, c = 38.832(3) A, and Z = 16.     

Tb4FeGe8 grown in liquid gallium: trans-cis chains from the distortion of a planar Ge square net

The ternary germanide Tb4FeGe8 was obtained from Ga flux reactions. The crystal structure studied with single-crystal X-ray diffraction revealed the existence of an orthorhombic average substructure (Cmcm, Z=1) with cell parameters a = 4.1118(14) A, b=15.844(5) A, and c=3.9885(15) A. The refinement [I > 2sigma(I)] converged to final residuals R1/wR2 = 0.0363/0.0893. The average structure (CeNiSi2-type) consists of a 3D [Fe1/4Ge2] framework where Ge atoms form a square net and Fe atoms reside alternatively above and below it with only 1/4 occupation probability. X-ray and electron diffraction studies showed a modulation in the Ge net. The modulated structure was refined based on a 4-fold monoclinic supercell (P2(1)/n) with parameters a = 5.7315(11) A, b = 15.842(3) A, c = 11.438(2) A, and beta = 91.724(4) degrees with R1/wR2 = 0.0643/0.1735 and uncovered a severe distortion of the Ge square net. The Ge atoms are displaced to form an array of cis-trans chains. The Ge-Ge distances within these chains are distinctively bonding, whereas those between the chains are nonbonding. Results of the electronic structure calculations and magnetic measurements are also reported. The structural distortions found in Tb4FeGe8 cast a doubt onto the correctness of many of the reported REM1-xGe2 disordered compounds and call for reinvestigation.     

Crystal Structure and Antitumor Activity of Tri[2-[N-（4′-methyl-benzylsulfonyl）amino]ethyl]-amine

The crystal structure of the title compound (C27H38N4O7S3, Mr = 626.79) has been determined by single-crystal X-ray diffraction. The crystal is of triclinic, space group Pīwith a = 9.411(1), b = 11.645(2), c = 14.672(2) (A。), α = 91.80(1), β = 95.36(1), γ =104.56(1)o, V = 1547.0 (A。)3, Z = 2, Dc = 1.346 g/cm3, λ = 0.71073 (A。), μ(MoKα) = 0.289 mm－1 and F(000) = 664. The structure was refined to R = 0.0406 and wR = 0.1177 for 4103 observed reflections with I > 2σ(I). X-ray diffraction analysis reveals that the title compound is a practically distorted tetrahedron and each molecule contains one lattice H2O by hydrogen bond. The antitumor activity of the title compound against HL-60 human leukemia cells has also been studied by MTT method.     

Solid phases of cyclopentane: combined experimental and simulation study

The phase diagram of cyclopentane has been studied by powder neutron diffraction, providing diffraction patterns for phases I, II, and III, over a range of temperatures and pressures. The putative phase IV was not observed. The structure of the ordered phase III has been solved by single-crystal diffraction. Computational modeling reveals that there are many equienergetic ordered structures for cyclopentane within a small energy range. Molecular dynamics simulations reproduce the structures and diffraction patterns for phases I and III and also show an intermediate disordered phase, which is used to interpret phase II.     

Crystal and magnetic structure of the double perovskite Sr2CoUO6: a neutron diffraction study

Sr2CoUO6 double perovskite has been prepared as a polycrystalline powder by solid-state reaction, in air. This material has been studied by X-ray, neutron powder diffraction (NPD) and magnetic measurements. At room temperature, the crystal structure is monoclinic, space group P2(1)/n, Z= 2, with a= 5.7916(2), b= 5.8034(2), c= 8.1790(3) A, beta= 90.1455(6)degrees. The perovskite lattice consists of a completely ordered array of CoO6 and UO6 octahedra, which exhibit an average tilting angle phi= 11.4 degrees. Magnetic and neutron diffraction measurements indicate an antiferromagnetic ordering below TN = 10 K. The low-temperature magnetic structure was determined by NPD, selected among the possible magnetic solutions compatible with the P2(1)/n space group, according with the group theory representation. The propagation vector is k= 0. A canted antiferromagnetic structure is observed below TN = 10 K, which remains stable down to 3 K, with an ordered magnetic moment of 2.44(7)mu(B) for Co2+ cations. The magnetic moment calculated from the Curie-Weiss law at high temperatures (5.22 mu(B)/f.u.) indicates that the orbital contribution is unquenched at high temperatures, which is consistent with high-spin Co2+((4)T(1g) ground state) in a quasi-regular octahedral environment. Magnetic and structural features are consistent with an electronic configuration Co2+[3d(7)]-U6+[Rn].     

V2AlC, V4AlC3-x (x approximately 0.31), and V12Al3C8: synthesis, crystal growth, structure, and superstructure

Single crystals of V2AlC and the new carbides V4AlC3-x and V12Al3C8 were synthesized from metallic melts. V2AlC was formed with an excess of Al, while V4AlC3-x (x approximately 0.31) and V12Al3C8 require the addition of cobalt to the melt. All compounds were characterized by XRD, EDX, and WDX measurements. Crystal structures were refined on the basis of single-crystal data. The crystal structures can be explained with a building-block system consisting of two types of partial structures. The intermetallic part with a composition VAl is a two-layer cutting of the hexagonal closest packing. The carbide partial structure is a fragment of the binary carbide VC1-x containing one or three layers. V2AlC is a H-phase (211-phase) with space group P63/mmc, Z=2, and lattice parameters of a=2.9107(6) A, and c=13.101(4) A. V4AlC3-x (x approximately 0.31) represents a 413-phase with space group P63/mmc, Z=2, a=2.9302(4) A, and c=22.745(5) A. The C-deficit is limited to the carbon site of the central layer. V12Al3C8 is obtained at lower temperatures. In the superstructure (P63/mcm, Z=2, a=5.0882(7) A, and c=22.983(5) A) the vacancies on the carbon sites are ordered. The ordering is combined to a small shift of the V atoms. This ordered structure can serve as a structure model for the binary carbides TMC1-x as well. V4AlC3-x (x approximately 0.31) and V12Al3C8 are the first examples of the so-called MAX-phases (MX)nMM' (n=1, 2, 3), where a deficit of X and its ordered distribution in a superstructure is proven, (MX1-x)nMM'.     

Powder diffraction study of a coordination polymer comprised of rigid building blocks: [Rh2(O2CCH3)4.mu2-Se2C5H8-Se,Se']infinity

The crystal structure of a new hybrid product comprised of two rigid building blocks, namely dirhodium(II) tetraacetate, [Rh(2)(O(2)CCH(3))(4)] (1), and 2,6-diselenaspiro[3.3]heptane, Se(2)C(5)H(8) (2), has been solved ab initio using laboratory source X-ray powder diffraction (XRPD) data. The rigid body refinement approach has been applied to assist in finding an adequate model and to reduce the number of the refined parameters. Complex [Rh(2)(O(2)CCH(3))(4).mu(2)-Se(2)C(5)H(8)-Se,Se'] (3) conforms to the triclinic unit cell with lattice parameters of a = 8.1357(4), b = 8.7736(4), and c = 15.2183(8) A, alpha = 77.417(3), beta = 88.837(3), and gamma = 69.276(4) degrees, V = 989.66(8) A(3), and Z = 2. The centrosymmetric P space group was selected for calculations. The final values of the reduced wR(p), R(p), and chi(2) were calculated at 0.0579, 0.0433, and 5.95, respectively. The structure of 3 is a one-dimensional zigzag polymer built on axial Rh...Se interactions at 2.632(6) A. The 2,6-diselenaspiro[3.3]heptane ligand acts as a bidentate linker bridging dirhodium units via both selenium atoms. The geometrical parameters of individual groups for rigid body refinement have been obtained from X-ray powder data for dirhodium(II) tetraacetate (1) and from single-crystal X-ray diffraction for diselenium molecule 2. The crystal structures of 1 and 2 are reported here for the first time. For 1 indexing based on XRPD data has resulted in the triclinic unit cell P with lattice parameters of a = 8.3392(7), b = 5.2216(5), and c = 7.5264(6) A, alpha = 95.547(10), beta = 78.101(6), and gamma = 104.714(13) degrees, V = 309.51(5) A(3), and Z = 1. The final values were wR(p) = 0.0452, R(p) = 0.0340, and chi(2) = 1.99. The 1D polymeric motif built on axial Rh.O interactions of the centrosymmetric dirhodium units has been confirmed for the solid-state structure of 1. Compound 2,6-diselenaspiro[3.3]heptane (2) conforms to the monoclinic space group P2(1)/c with the unit cell parameters of a = 5.9123(4), b = 19.6400(13), and c = 5.8877(4) A, beta = 108.5500(10) degrees, V = 648.15(8) A(3), and Z = 4.     

Ce4

The yellow-orange oxonitridosilicate oxide Ce4[Si4O4N6]O was obtained by the reaction of cerium metal with Si(NH)2 and SiO2 in a radiofrequency furnace at 1560 degrees C. The crystal structure was determined by single-crystal X-ray diffraction (a = 1033.67(6) pm, P2,3, Z = 4, R1 = 0.0412, wR2 = 0.0678) and powder neutron diffraction. In the solid there are complex cations [Ce4O]10+ that are enveloped by a hyperbolical layer structure [Si4O4N6]10-. The layer is built up by corner-sharing SiON3 tetrahedra of Q3 type. The oxygen atoms of the SiON3 tetrahedra are terminally bound to Si, while all nitrogen atoms bridge two neighboring Si centres. The crystallographic differentiation of O and N was unequivocally possible by a careful evaluation of the single-crystal X-ray diffraction data combined with lattice-energy calculations by using the MAPLE concept (Madelung part of lattice energy). Furthermore the results were confirmed by the chemical analyses. Subsequently, the determined N/O distribution and their crystallographic ordering was proved by neutron powder diffraction. In accordance with the molar ratio Si:(O,N) = 2:5 the [Si4O4N6]10- network may be classified as a layer silicate. In this specific case a hyperbolically corrugated topology of the layers is observed; this is correlated to periodic nodal surface (PNS) representatives.     

1-苯基-3-甲基-4-(6-氢-4-甲基氨基-5-硫杂-2,3-吡嗪)-吡唑啉酮的合成与晶体结构

通过1-苯基-3-甲基-4-氯乙酰基-吡唑啉酮-5 (PMCP) 和4-甲基氨基硫脲 (MTSC) 缩合, 形成了一种新的双杂环化合物 (PMCP-MTSC)。利用元素分析与单晶X-射线衍射进行了表征。 该化合物(C14H15N5OS)属单斜晶系, P21 空间群, 晶体学参数为 a = 7.634(1), b = 11.639(2), c = 8.150(2) ? ?= 98.13(1), V = 716.9(2) ?, Z = 2, Dc = 1.396 g/cm3, (MoKa) = 0.232 mm-1, F(000) = 316, Mr = 301.37。结构由直接法解出,共收集3114个衍射点,其中I > 2(I)的独立衍射点有2453个,用全矩阵最小二乘法修正,最终偏离因子:R = 0.0294, wR = 0.0738。结构分析表明: 该化合物以酮式存在,分子间通过氢键作用(N(5)H…O)连接起来并形成一维链状结构。     

Crystal Structure of Indenyl—3—indenyl

1 INTRODUCTION Indene is an intermediate used for the synthesis of organometallic complexes involving silylene-bridged indenyl[1～5]. In the process of synthesizing (CH3)(C6H5)Si(Ind)2[6], a new compound as a by-product which is a dimer of indene was obtained, and only one similar crystal was found in CCDC[7]. Up to now, there are no crystal structure reports on this kind of structure. The present paper will describe the crystal structure of the title compound. 2 EXPERIMEN…     

Molecular structure of a D-homoandrostanyl steroid derivative: single crystal and powder diffraction analyses

The knowledge of the structure of a molecular crystal is frequently a prerequisite for the understanding of its solid state properties. Even though single-crystal diffractometry is the method of choice when it comes to crystal structure determination, methods using powder diffraction data become more and more competitive. There has been much recent interest in the development of a new generation of "direct-space" approaches that are particularly suited for molecular crystals. The crystallographic structure of a steroid derivative molecule (17,17-di-n-propyl-17a-aza-D-homo-5alpha-androstan-3beta-ol) was obtained in two independent ways: from a single crystal by laboratory X-rays and from a polycrystalline powder by high-resolution synchrotron powder diffraction. The molecule crystallizes in the orthorhombic space group P2(1)2(1)2(1) (a = 6.5346, b = 17.6006 and c = 19.6978 A). Hydrogen bonds form infinite chains of molecules parallel to the c axis.     

Li3[ScN2]: the first nitridoscandate(III)-tetrahedral Sc coordination and unusual MX2 framework

Li(3)[ScN(2)] was prepared from Li(3)N with Sc or ScN in a nitrogen atmosphere at 1020 K as a light yellow powder with an optical band gap of about 2.9 eV. The crystal structure was refined based on X-ray and neutron powder diffraction data (Ia$\bar 3$, Z=16, X-ray diffraction: R(profile)=0.078, R(Bragg)=0.070; Neutron diffraction: R(profile)=0.077, R(Bragg)=0.074; Rietfeld: a=1003.940(8) pm, Guinier: a=1004.50(3) pm). Li(3)[ScN(2)] is an isotype of Li(3)[AlN(2)] and Li(3)[GaN(2)] and crystallizes in an ordered superstructure of the Li(2)O structure type, leading to a three-dimensional framework of all-vertex-sharing tetrahedra 3[infinity[ScN[4/2][3-]]. Li is displaced from the center of a tetrahedron of N atoms in the direction of one trigonal face. Li(3)[ScN(2)] decomposes above 1050 K to form ScN and Li(3)N. Calculations of the periodic nodal surface (PNS) and of the electron localization function (ELF) support the picture of a covalent Sc-N network separated from isolated Li cations, whereby scandium d orbitals are involved in the chemical bonding.     

Synthesis, Crystal Structure, Thermal Stability and Luminescent Properties of a New 2D Zinc Complex

A new coordination polymer associated with zinc ion,[Zn(Tda)(bpp)] n (1,H 2 tda=thiophene-2,5-dicarboxylic acid,bpp=1,3-bis(4-pyridyl)propane),was prepared under solvothermal conditions,and characterized by single-crystal X-ray diffraction,elemental analysis and IR spectra.The complex belongs to monoclinic,space group P2 1 /c with a=9.8799(4),b=12.0430(6),c=15.4269(9),β=95.424(5) o,V=1827.33(16) 3,Z=4,D c=1.577 g/cm 3,S=1.074,μ=1.486 mm-1,F(000)=888,M r=433.80,R=0.0359 and wR=0.0968 for 2685 observed reflections (I > 2σ(Ⅰ)).Complex 1 displays an interesting 2D lattice structure.In 1,four coordinated zinc ions were bridged by Tda and bpp ligands to generate a (4,4) two-dimensional layer.The thermogravimetric analysis,powder X-ray diffraction (XRD) and luminescent properties for 1 also have been explored.     

Synthesis and Crystal Structure of 6—Bromo—piperonal—dimethyl—acetal

1 INTRODUCTION 6-Bromo-piperonal-dimethyl-acetal is an intermediate used for the synthesis of natural products, such as podophyllotoxin[1] and the related compounds[2～6] due to the useful biological activities associated with some of its derivatives[7, 8]. In particular, glycoside derivatives of 4?dimethyl- 4-epipodophyllotoxin have been used in cancer chemotherapy[9, 10]. The title compound has been synthesized from raw material piperonal, after bromo substitution and acetal protection…     

Synthesis and Crystal Structure of Tetrakis（4—methylpyridine）bis（μ4—pentathio）—tetracopper（Ⅰ）（4—methylpyridine）solvate

1 INTRODUCTION An interesting aspect in the studies of copper-sulfur coordination chemistry is the apparent tendency of Cu(Ⅰ) ions to form various clusters with sulfur ligands. The coordination chemistry of Cu(Ⅰ) has been studied extensively owing to the importance of Cu(Ⅰ) in biological systems and copper-sulfur bonds detected in some metallopro- teins[1]. More recently, remarkably rich photoluminescence properties have been found in the tetranuclear complexes[2～5] and the cage-ty…     

Synthesis, structural characterization, and thermal stability of a new layered germanate structure, Na4Ge16O28(OH)12

The new layered germanate structure Na4Ge16O28(OH)12 has been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, FTIR, and SEM. The crystal lattice parameters are a = 7.3216(6) A, b = 14.3986(9) A, c = 7.7437(6) A, alpha = 90.0 degrees, beta = 100.179(7) degrees, gamma = 90.0 degrees, and V = 803.5(1) A3. The space group is C2/m with Z = 1. The germanium oxide sheets are connected non-covalently via electrostatic interactions with the sodium cations and H-bridging. At temperatures above 400 degrees C, the structure starts decomposing into sodium enneagermanate (Na4Ge9O20), germanium dioxide, and water as determined by powder X-ray diffraction, TGA, DTA, DSC, and GCMS.     

Synthesis,structure, and magnetic properties of two new vanadocarboxylates with three-dimensional hybrid frameworks

(V(III)(OH))(2)[C(6)H(2)(CO(2))(4)].4H(2)O (labeled MIL-60) and V(III)(OH)[(2)(O(2)C)C(6)H(2)(COOH)(2)].H(2)O (labeled MIL-61) were hydrothermally synthesized from mixtures of VCl(3), 1,2,4,5-benzenetetracarboxylic acid, and water heated for 3 days at 473 K. The structure of MIL-60 was solved from single-crystal X-ray diffraction data in the triclinic centrosymmetric P1 (No. 2) space group with lattice parameters a = 6.3758(5) A, b = 6.8840(5) A, c = 9.0254(5) A, alpha = 69.010(2) degrees, beta = 85.197(2) degrees, gamma = 79.452(2) degrees, V = 363.53(5) A(3), and Z = 1. The structure of MIL-61 was ab initio determined from an X-ray powder diffraction pattern. MIL-61 crystallizes in the Pnma (No. 62) orthorhombic space group with lattice parameters a = 14.8860(1) A, b = 6.9164(1) A, c = 10.6669(2) A, V = 1098.23(3) A(3), and Z = 4. Both structures contain the same inorganic building block that consists of trans chains of V(III)O(4)(OH)(2) octahedra. The three-dimensional frameworks of MIL-60 and MIL-61 are constituted by the linkage of these chains via the organic molecules so delimiting the channels or cages where the water molecules are encapsulated. The magnetic behavior of these two phases is presented: MIL-60 is paramagnetic, and MIL-61 antiferromagnetically orders below T(N) = 55(5) K.     

硝酸铕18-C-6(4:3)络合物的晶体结构

标题化合物的分子式为[Eu(NO₃)₆][Eu(NO₃)₂C₁₂H₂₄O₆]₃。晶体属单斜晶系,空间群为C2/m,a=28.772(6),b=11.142(2),c=12.024(2)Å,β=112.63(2)°,Z=2。对1167个可观察反射(I≥3σ(I)),用块矩阵最小二乘法精修所有的结构参数,最后的一致性因子R=0.063。结构分析表明:晶体学上有三个不同的离子,(1)[Eu(NO₃)₆]^3-,(2)[Eu(NO₃)₂C₁₂H₂₄O₆]⁺(有序)和(3)[Eu(NO₃)₂C₁₂H₂₄O₆]⁺(无序)。前两个离子都具有C_2h对称性。第三个离子是C₁对称性,它有一个无序的冠醚环。在Fourier图上二个冠醚环叠加,它们的相互交错角为32°。