225 resultados para Crystal atomic structure


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The crystal structure of Sm(HTH)(3)Phen [HTH: 4,4,5,5,6,6,6-heptafluoro-1-(2-thienyl)-1,3-hexanedione, Phen: 1,10-Phenanthroline] has been determined by single crystal X-ray diffraction and the coordination geometry of Sm atom is a dodecahedron. The complex can give the characteristic luminescence of Sm3+ upon UV excitation.

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The reaction of trivacant precursor Nag [A-PW9O34] . 19H(2)O with Ti(SO4)(2) affords the novel dimeric, di-Ti-IV-substituted tungstophosphate K4Na6[alpha-1,2-PW10Ti2O39](2) . 14H(2)O. The X-ray structural determination shows the dimeric, anhydride structure was formed by two Ti-O-Ti bonds linking two di-titanium-substituted Keggin anion [alpha-1,2-PW10Ti2O40]. It was also characterized by elemental analysis, TGA, FT-IR and U-V-vis spectroscopies.

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Nanostructure and morphology and their development of poly(di-n-hexylsilane) (PDHS) and poly(di-n-butylsilane) (PDBS) during the crystal-mesophase transition are investigated using small angle X-ray scattering (SAXS), wide angle X-ray diffraction and hot-stage atomic force microscopy. At room temperature, PDHS consists of stacks of lamellae separated by mesophase layers, which can be well accounted using an ideal two-phase model. During the crystal-mesophase transition, obvious morphological changes are observed due to the marked changes in main chain conformation and intermolecular distances between crystalline phase and mesophase. In contrast to PDHS, the lamellae in PDBS barely show anisotropy in dimensions at room temperature. The nonperiodic structure and rather small electronic density fluctuation in PDBS lead to the much weak SAXS. The nonperiodic structure is preserved during the crystal-mesophase transition because of the similarity of main chain conformation and intermolecular distances between crystalline phase and mesophase.

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The title complex [(VB1)(2)DMFHPMo12O40.5DMF, VB1 = vitamin B-1 (thiamine chloride), DMF = N,N-dimethylformamide] has been synthesized and characterized by elemental analysis, IR, UV-Vis, electron spin resonance, X-ray photoelectron spectroscopy and cyclic voltammetry methods. The X-ray crystal structure revealed that there is one independent molecule in the unit cell of the title complex that contains one mixed-valence heteropolyanion, two VB1+ cations and six DMF molecules. The title complex possesses a centrosymmetrical arrangement in the unit cell, with the P atom at the symmetry center of the heteropolyanion and with eight O atoms surrounding the central P atom, such that two sets of PO4 tetrahedra are formed. The PO4 tetrahedra and MoO66-(7-) octahedra are disordered in the heteropolyanion. The bond distances of P-O-a and Mo=O-d are in the ranges 1.57 (4)-1.70 (4) Angstrom and 1.61 (2)-1.67 (2) Angstrom, respectively.

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A perfect single crystal of nylon-2,14 was prepared from 0.02% (w/v) 1,4-butanediol solution by a "self-seeding" technique and isothermal crystallization at 120 and 145 degreesC. The morphology and structure features were examined by transmission electron microscopy with both image and diffraction modes, atomic force microscopy, and wide-angle X-ray diffraction (WAXD). The nylon-2,14 single crystal grown from 1,4-butanediol at 145 degreesC inhabited a lathlike shape with a lamellar thickness of about 9 nm. Electron diffraction and WAXD data indicated that nylon-2,14 crystallized in a triclinic system with lattice dimensions a = 0.49 nm, b = 0.51 nm, c = 2.23 nm, alpha = 60.4degrees, beta = 77degrees, and gamma = 59degrees. The crystal structure is different from that of nylon-6,6 but similar to that of other members of nylon-2Y.

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A layered inner-tunnel supramolecular compound 1, [(CuI)(2)(o-phen)(2)], was hydrothermally synthesized and structurally characterized by X-ray crystal diffraction. It crystallizes in triclinic system, space group P (1) over bar with a=0.7759(2) nm, b=0.9070(2) rim, c=0.91894(10) rim, alpha=96.306(14)degrees, beta=104.567(16)degrees, gamma=109.421(19)degrees, V=0.5768(2) nm(3), Z=1, R=0.0348, omegaR=0.0920.

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An unusual composite hybrid material [Co-4 (phen)(8) (H2O)(2) (HPO3)(2)](H3O)(3) [PMo8VI V-4(IV) O-40 ((VO)-O-IV) 2] 1 (phen = 1,10-phenanthroline) has been hydrothermally synthesized from a mixture of NH4VO3, Na2MoO4.2H(2)O, CoCl2.6H(2)O, phen, H3PO3 and water. It was characterized by elemental analysis, IR, UV-vis, XPS, EPR, TG and single crystal X-ray diffraction. The title compound is constructed from the organic-inorganic hybrid [Co-4(phen)(8)(H2O)(2) (HPO3)(2)](4+) and highly reduced bi-capped pseudo-Keggin [(PMo8V4O40)-V-VI-O-IV ((VO)-O-IV)(2)](7-) polyoxoanions The structure exhibits an extended 2D network through hydrogen bonds among cations, anions and H2O, combining polyoxometalates with metal phosphonates for the first time.

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A novel compound [Ni(phen)(3)](2)[(SiMo10V1/2O40)-O-V((VO)-O-IV)(2)] . 2H(2)O has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. The compound crystallizes in the triclinic, system, space group P-1, a = 12.378(4) Angstrom, b = 14.148(5) Angstrom, c = 14.316(2) Angstrom, alpha = 105.91(2)degrees, beta = 95.31(2)degrees, gamma = 96.89(3)degrees, V = 2373.0(12) Angstrom(3), Z = 1, (lambdaMo(Kalpha)) = 0.71073 Angstrom, R1 (wR2) = 0.0869(0.2174). Data were collected on a Siemens P4 four-circle diffractometer at 293 K in the range of 1.51 < theta < 22.50degrees using the omega-scan technique. Empirical absorption correction (psi scan) was applied. The structure was solved by the direct method and refined by the Full-matrix least-squares on F-2 using the SHELXL-97 software. X-ray crystallographic study showed that the title compound contained a bi-capped alpha-Kegin-type [(SiMo10V2O40)-O-IV((VO)-O-IV)(2)](4-) polyoxoanion.

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The first crystal structure of tris(methylcyclopentadienyl) tetrahydrofuranato (THF) lanthanide complexes, (CH3Cp)(3)Sm . THF, is determined. The complex crystallizes from mixed solvents of tetrahydrofuran and hexane as a monomer in the orthorhombic space group Pc2(1)n with the unit cell parameters a = 9.135(2) Angstrom, b = 13.263(2) Angstrom, c = 16.176(3) Angstrom, and Z = 4.

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Themorphologies and structures of single crystals of syndiotactic poly(propene-co-1-butene) (PPBU) with 1-butene contents of 2.6, 4.2, 9.9, 16.2, and 47.9 mol % are studied by transmission electron microscopy and electron diffraction. The electron diffraction results show that the 1-butene units are included in the crystalline phase of the sPP homopolymer. A small amount of 1-butene (<4.2 mol %) has no significant influence on the antichiral chain packing of sPP. With increasing content of 1-butene units, an increasing packing disorder is observed in the PPBU copolymers. The antichiral packing model is, however, always the predominant chain packing structure of the copolymers with the analyzed composition. Bright-field electron microscopy observation shows that the PPBU single crystals exhibit always regular rectangular or lathlike shapes with preferred growth direction along their crystallographic b-axes owing to their packing features. The incorporated 1-butene units influence the crystallization behavior of sPP distinctly. With the increase of the 1-butene units, the aspect ratio of the single crystals increases. Furthermore, the typical transverse microcracks and ripples of the highly stereoregular sPP are no more so prominent for the copolymers. The microcracks are occasionally observed in the single crystals of copolymers with low 1-butene content (less than or equal to4.2 mol %), while transverse ripples are only seen in the crystals of the copolymer having a 1-butene content of 9.9 mol %. With a further increase in the content of 1-butene units, the copolymers behave like the low stereoregular sPP, where neither cracks nor ripples are observed any more.

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A novel compound [Cu(en)(2)](4)[(SiMo8V4O40)-O-v(V-IV O)(2)] [MoO4](2) . 5H(2)O has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Black crystals crystallize in the tetragonal. system, space group 14/m, a = b = 14.019(2) Angstrom, c = 20.341(4) Angstrom, V = 3997.9(11) Angstrom(3), Z = 2, lambda(MoKalpha) = 0.71073 Angstrom (R(F) = 0.0443 for 1819 reflections). Data were collected on a Siemens P4 four-circle diffractometer at 293 K in the range of 1.76 < theta < 24.98degrees using the omega-scan technique. The structure was solved by the direct method and refined by the full-matrix least squares on F-2 method using the SHELXL-97 software. X-ray crystallographic study showed that the title compound contained a bicapped alpha-Keggin fragment [SiMo8 (V4O40)-O-v((VO)-O-IV)(2)](4-) polyoxoanion.

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A new bimetallic cluster complex with the formula [{Co(phen)(2)}(2)V4O12](H2O)-H-. was synthesized from the hydrothermal reaction of V2O5, H2C2O4, Co(NO3)(2), 1,10-phenanthroline (phen), (C4H9)(4)NOH and water. The compound crystallizes in an orthorhombic system with space group Pbcn and unit cell parameters a = 19.106(3) Angstrom, b = 15.250(3) Angstrom, c = 16.321(2) Angstrom, V = 4755.4(13) Angstrom(3), Z = 4 and R = 0.0318. The bimetallic cluster complex [{Co(phen)(2)}(2)V4O12](H2O)-H-. is composed of a discrete V4O124- cluster eovalently attached to two [Co(phen)(2)](2+) fragments and the discrete hexanuclear bimetallic clusters of [{Co(phen)(2)}(V4O12)-V-2](H2O)-H-. are further extended into interesting three-dimensional supermolecular arrays via pi-pi stacking interactions of phen groups. Other characterizations by elemental analysis, IR, and thermal analysis are also described.

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[NH3CH2CH2CH2NH2][NH3CH2CH2CH2NH3](2)[(As2AsMo8V4O40)-As-III-Mo-V-O-IV].3H(2)O was hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. Crystal data: monoclinic, C2/c, a = 45.375(9) Angstrom, b = 11.774(2) Angstrom, c = 23.438(5) Angstrom, beta = 96.62(3)degrees. X-ray crystallographic study showed that the crystal structure was constructed by bicapped alpha-Keggin fragments [(As2AsMo8V4O40)-As-III-Mo-V-O-IV](5-) polyoxoanion. The title compound had a high catalytic activity for the oxidation of benzaldehyde to benzoic acid using H2O2 as oxidant in a liquid-solid biphase system.

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The title heteropoly blue, (Bu4N)(6)H-10 [(PMo11MoO40)-Mo-VI-O-V](4) . H2O has been photochemically synthesized and characterized with elemental analysis, solid diffusion reflectance electronic spectra, CV, ESR, XPS, IR spectra, conductivity measurement and X-ray single crystal analysis. The crystallographic data for C96H218Mo48N6O169P4 are as follows: M-r = 8889.76, triclinic, P (1) over bar, a = 1.4142 (3) nm, b = 2.6027 (5) nm, c = 2.6403(5) nm, alpha = 113.96(3)degrees, beta = 90.05(3)degrees, gamma = 105.71(3)degrees, V = 8.481 (3) nm(3), Z = 1, D-c = 1.741 g/cm(3), F (000) = 4264, mu = 1.798 mm(-1). The X-ray crystal structure analysis reveals that there Is one independent molecule in the unit cell of the title heteropoly blue which contains four mixed-valence heteropoly anions, six tetrabutylammonium cations and one water molecule. Its molecular structure possesses a centrosymmetrical arrangement in the unit cell. The phosphorus atom is In the crystallographic inversion center of the heteropoly anion and the eight oxygen atoms surrounding central phosphorus atom comprise of a distorted hexahedron. Heteropolyanion has two equal sets of PO4 tetrahedron. The PO4 tetrahedron and the MoO6 octahedron in the polyanion are greatly distorted.

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Rare earth complex (C5H9C9H6)(3)SmCl-Li+ (THF)(4)( I ) was synthesized by reacting anhydrous SmCl3 with two equivalents of C5H9C9H6Li. From mix-solvent of THF and hexane, red color single crystals were obtained. The crystal belongs to a cubic system, space group P2(1)3 with unit cell parameters a= b=c= 1. 754 0(2) nm, alpha=beta=gamma=90degrees, V=5. 396 4(11) nm(3), Z = 4. The ten-coordinated samarium atom is bonded to three cyclopentylindenyl rings and a chlorine atom to form the anionic part of the title complex, ring centroids and the chlorine atom form a tortured tetrahedron around samarium. In the cationic part, lithium atom coordinates to four oxygen atoms of THF molecules to form a normal tetrahedron. The Sm-C(within the same ring) distance varies from 0. 268 to 0. 299 nm.