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  • 651. Xu, Changming
    et al.
    Cai, Yanbing
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Flodström, Katarina
    Li, Zheshen
    Esmaeilzadeh, Saeid
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Zhang, Guo-Jun
    Spark plasma sintering of B4C ceramics: The effects of milling medium and TiB2 addition2012In: International journal of refractory metals and hard materials, ISSN 0263-4368, Vol. 30, no 1, p. 139-144Article in journal (Refereed)
    Abstract [en]

    Boron carbide (B4C) ceramics, with a relative density up to 98.4% and limited grain growth, were prepared at 1600-1800 degrees C by spark plasma sintering (SPS) technique. The effects of powder milling medium (water and 2-propanol) on the powders' surface characteristics and TiB2 addition on the sintering densification were investigated. The ball milling processing of B4C powders in water can promote the sintering of B4C ceramics. A B2O3 layer on B4C particle surface is concluded to promote the densification of the B4C ceramics at an early sintering stage. This B2O3 layer, which normally inhibits the densification process at the final stage of the sintering, can be reduced through reaction with TiB2 particles, resulting in further densification of the B4C ceramics.

  • 652. Xu, Changming
    et al.
    Cai, Yanbing
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Katarina, Flodström
    Jansson, Kjell
    Li, Zheshen
    Zhu, Guoqiang
    Esmaeilzadeh, Saeid
    Spark Plasma Sintering of B4C Ceramics: The Effects of Milling Medium and TiB2 AdditionIn: Journal of Marerials Research, ISSN 0884-2914Article in journal (Refereed)
  • 653. Xu, W. Z.
    et al.
    Sun, Junliang
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry. Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry, Department of Structural Chemistry.
    Huang, Z. T.
    Zheng, Q. Y.
    Molecular encapsulation of a discrete (H2O)(32) cluster with S-6 symmetry in an organic crystalline supermolecule2009In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, no 2, p. 171-173Article in journal (Refereed)
    Abstract [en]

    A discrete S-6-symmetrical (H2O)(32) cluster was encapsulated in the cavity of an organic co-crystalline supermolecule constructed by the co-crystallization of guanidinium and benzenetribenzoate ions through hydrogen bonds, pi-pi and cation-pi interactions.

  • 654. Xu, Yunhua
    et al.
    Åkermark, Torbjörn
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Gyollai, Viktor
    Zou, Dapeng
    Eriksson, Lars
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Duan, Lele
    Zhang, Rong
    Åkermark, Björn
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Sun, Licheng
    A New Dinuclear Ruthenium Complex as an  Efficient for Water Oxidation Catalyst2009In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 48, no 7, p. 2717-2719Article in journal (Refereed)
    Abstract [en]

    A dinuclear ruthenium complex, which acts as a molecular catalyst for water oxidation, has been synthesized and characterized. The electronic and electrochemical properties were studied by UV−vis spectroscopy and cyclic voltammetry. The oxidation potentials of the complex are significantly lowered by introducing a negatively charged carboxylate ligand, in comparison with those of the reported complexes that have neutral ligands. The catalytic activity of the complex toward water oxidation using Ce(NH4)2(NO3)6 as a chemical oxidant was investigated by means of an oxygen electrode and mass spectrometry. The turnover number of this catalyst with CeIV as the chemical oxidant was found to be ca. 1700. The mass spectroscopic analysis of the isotopomer distribution in oxygen evolved from 18O-labeled water indicates that O atoms in the evolved oxygen originate from water

  • 655. Yan, Haixue
    et al.
    Zhang, Hongtao
    Ubic, Rick
    Reece, Michael. J
    Liu, Jing
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Shen, Zhijian
    Zhang, Zhen
    A Lead Free High Curie Point Ferroelectric Ceramic, CaBi2Nb2O92005In: Advanced Materials, ISSN 0935-9648, Vol. 17, no 10, p. 1261-1265Article in journal (Refereed)
  • 656. Yang, Chia-Min
    et al.
    Lin, Ching-Yi
    Sakamoto, Yasuhiro
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry, Structural Chemistry.
    Huang, Wei-Chia
    Chang, Li-Ling
    2D-Rectangular c2mm mesoporous silica nanoparticles with tunable elliptical channels and lattice dimensions2008In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, no 45, p. 5969-5971Article in journal (Refereed)
    Abstract [en]

    Mesoporous silica nanoparticles with a two-dimensional center-rectangular (plane group c2mm) lattice and coiled elliptical channels have been synthesized; the new synthetic route also allows simple control over the lattice dimensions and the elliptical shape of the channels.

  • 657. Yang, T.
    et al.
    Ju, J.
    Li, GB
    Jang, SH
    Sun, Junliang
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Liao, FH
    Lin, JH
    Sasaki, J.
    Toyota, N.
    MH2P2O7 (M = Co, Ni): Metamagnetic interaction between the zigzag octahedral chains2007In: Inorganic Chemisty, Vol. 46, p. 2342-2344Article in journal (Refereed)
  • 658. Yang, T.
    et al.
    Ju, J.
    Li, G.B.
    Liao, F.H.
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Deng, F.
    Chen, L.
    Wang, Y.X.
    Lin, J.H.
    Square-pyramidal/triangular framework oxide: synthesis and structure of PKU-62007In: Inorganic Chemistry, Vol. 46, p. 4772-4774Article in journal (Refereed)
  • 659. Yang, T
    et al.
    Sun, Junliang
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Li, G
    Wang, Y
    Christensen, J
    He, Z
    Christensen, K-E
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Liao, F
    Lin, J
    Fe5O5[B6O10(OH)3nH2O: Wave-layered Iron Borate and Frustrated Antiferromagnetism2009In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 48, no 23, p. 11209-11214Article in journal (Refereed)
    Abstract [en]

    The first layered iron borate, Fe5O5[B6O10(OH)3nH2O, has been prepared by the boric acid flux method. Its structure, determined by single crystal X-ray diffraction, contains a double FeO6-octahedral layer and an unusual [B6O13] chain. The rigid and cambered [B6O13] chains bend the octahedral layers, resulting in a wave-like and sandwiched structure. Crystallographic study indicates the structural modulation is mainly from the [B6O13] chains because of the insertion of water molecules in between. Nevertheless, FeO6 layers in the average structure, which are well separated by borate chains, is still a reasonable model to understand the two-dimensional magnetism. The strong antiferromagnetic interactions and the complex Fe3+-net suggest a possible geometrically magnetic frustration, which may be the reason for the second-order temperature-induced magnetic transition at 125 K. The condensed Fe3+ layers and the relatively low redox potential at about 1.25 V versus Li+/Li show its potentials as an anodic material.

  • 660. Yang, Tao
    et al.
    Lin, Jianhua
    Liao, Fuhui
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Eriksson, Lars
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Li, Guobao
    Sun, Junliang
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Na8[Cr4B12P8O44(OH)4] [P2O7]•nH2O: A 3D Borophosphate Framework with Spherical Cages2008In: Chemistry A European Journal, Vol. 14, p. 7212-7217Article in journal (Refereed)
  • 661. Yang, Tao
    et al.
    Lin, Jianhua
    Liao, Fuhui
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Li, Guobao
    Eriksson, Lars
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Sun, Junliang
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Na5[MB24O34(OH)12]•nH2O (M=Cr3+, Al3+): Unprecedented Sphere-like Polyborate Clusters from Boric Acid Flux Synthesis2008In: Inorganic Chemistry, Vol. 47, p. 3228-3233Article in journal (Refereed)
  • 662.
    Yang, Ye
    et al.
    Nanyang Technological University, Singapore.
    Lyubartsev, Alexander
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry, Department of Physical Chemistry. Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Korolev, Nikolai
    Nanyang Technological University, Singapore.
    Nordenskiöld, Lars
    Nanyang Technological University, Singapore.
    Computer Modeling Reveals that Modifications of the Histone Tail Charges Define Salt-Dependent Interaction of the Nucleosome Core Particles2009In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 96, p. 2082-2096Article in journal (Refereed)
    Abstract [en]

    Coarse-grained Langevin molecular dynamics computer simulations were conducted for systems that mimic solutions of nucleosome core particles (NCPs). The NCP was modeled as a negatively charged spherical particle representing the complex of DNA and the globular part of the histones combined with attached strings of connected charged beads modeling the histone tails. The size, charge, and distribution of the tails relative to the core were built to match real NCPs. Three models of NCPs were constructed to represent different extents of covalent modification on the histone tails: (nonmodified) recombinant (rNCP), acetylated (aNCP), and acetylated and phosphorylated (paNCP). The simulation cell contained 10 NCPs in a dielectric continuum with explicit mobile counterions and added salt. The NCP-NCP interaction is decisively dependent on the modification state of the histone tails and on salt conditions. Increasing the monovalent salt concentration (KCl) from salt-free to physiological concentration leads to NCP aggregation in solution for rNCP, whereas NCP associates are observed only occasionally in the system of aNCPs. In the presence of divalent salt (Mg2+), rNCPs form dense stable aggregates, whereas aNCPs form aggregates less frequently. Aggregates are formed via histone-tail bridging and accumulation of counterions in the regions of NCP-NCP contacts. The paNCPs do not show NCP-NCP interaction upon addition of KCl or in the presence of Mg2+. Simulations for systems with a gradual substitution of K+ for Mg2+, to mimic the Mg2+ titration of an NCP solution, were performed. The rNCP system showed stronger aggregation that occurred at lower concentrations of added Mg2+, compared to the aNCP system. Additional molecular dynamics simulations performed with a single NCP in the simulation cell showed that detachment of the tails from the NCP core was modest under a wide range of salt concentrations. This implies that salt-induced tail dissociation of the histone tails from the globular NCP is not in itself a major factor in NCP-NCP aggregation. The approximation of coarse-graining, with respect to the description of the NCP as a sphere with uniform charge distribution, was tested in control simulations. A more detailed description of the NCP did not change the main features of the results. Overall, the results of this work are in agreement with experimental data reported for NCP solutions and for chromatin arrays.

  • 663. Yaoquan, Tu
    et al.
    Laaksonen, Aatto
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Towards Fast and Reliable Quantum Chemical Modelling of Macromolecules2007In: New Algorithms for Macromolecular Simulation, 2007, p. 315-341Chapter in book (Refereed)
  • 664. Yaoquan, Tu
    et al.
    Lennart, Nilsson
    Laaksonen, Aatto
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    A highly efficient ab initio tight-binding-like approximate density-functional2007In: Lecture Notes in Computer Science, 2007, p. 100-108Chapter in book (Refereed)
  • 665. Ying, Wan
    et al.
    Wang, Haiyan
    Zhao, Qingfei
    Klingstedt, Miia
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Zhao, Dongyuan
    Ordered Mesoporous Pd/Silica-Carbon as a Highly Active Heterogeneous Catalyst for Coupling Reaction of Chlorobenzene in Aqueous Media2009In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 131, no 12, p. 4541-4550Article in journal (Refereed)
    Abstract [en]

    Heterogeneous palladium catalysts, which are supported on ordered mesoporous silica-carbon nanocomposites, have been applied in water-mediated coupling reactions of chlorobenzene without assistance of any phase-transfer catalysts. Characterization by XRD, TEM, N2 sorption, FT-IR, TG, XPS, and H2 chemisorption techniques reveals the highly ordered mesostructure, high surface areas (?345 m2/ g), large pore volumes (?0.46 cm3/g), uniform mesopore sizes (?6.3 nm), hybrid silicate and carbonaceous compositions, and a high dispersion of palladium nanoparticles (about 3 nm) in the mesopores. The catalyst exhibits a high yield for trans-stilbene (?60%) in the Heck coupling reaction of chlorobenzene and styrene at 100 ‹C and for biphenyl (46%) in the Ullmann coupling reaction of chlorobenzene at 30 ‹C, using water as a solvent. When substituted aryl chlorides (hydroxyl, methoxyl, and methyl) are involved in the Ullmann reaction, the yields of symmetrical substituted biphenyl are also higher than 44% (this value reaches 86% for the coupling reaction of 4-chlorophenol) at a low temperature of 30 ‹C. This heterogeneous catalyst is stable, which shows negligible metal leaching, and can be reused more than 20 times. For comparison, the catalytic activities for Pd catalysts supported on pure mesoporous polymeric, carbonaceous, and silicate frameworks are also investigated. The results clearly indicate that the pore wall nature shows great influence on the dispersion of metallic Pd species and, in turn, the catalytic performance.

     

  • 666. Yoshizawa, Kazuhiro
    et al.
    Toyota, Shinji
    Toda, Fumio
    Kato, Masako
    Csöregh, Ingeborg
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    A new organic zeolite created by molecular aggregation of 1,1-bis(3,4-dihydroxyphenyl)cyclohexane in the solid state2007In: CrystEngCommArticle in journal (Refereed)
  • 667. You, TS
    et al.
    Lidin, Sven
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Gourdon, O
    To What Extent Does the Zintl-Klemm Formalism Work? : The Eu(Zn1-xGex)(2) Series2009In: Inroganic Chemistry, Vol. 48, no 14, p. 6380-6390Article in journal (Refereed)
    Abstract [en]

    The series of ternary polar intermetallics Eu(Zn1−xGex)2 (0 ≤ x ≤ 1) has been investigated and characterized by powder and single-crystal X-ray diffraction as well as physical property measurements. For 0.50(2) ≤ x < 0.75(2), this series shows a homogeneity width of hexagonal AlB2-type phases (space group P6/mmm, Pearson symbol hP3) with Zn and Ge atoms statistically distributed in the planar polyanionic 63 nets. As the Ge content increases in this range, a decreases from 4.3631(6) Å to 4.2358(6) Å, while c increases from 4.3014(9) Å to 4.5759(9) Å, resulting in an increasing c/a ratio. Furthermore, the Zn−Ge bond distance in the hexagonal net drops from 2.5190(3) Å to 2.4455(3) Å, while the anisotropy of the displacement ellipsoids significantly increases along the c direction. For x < 0.50 and x > 0.75, respectively, orthorhombic KHg2-type and trigonal EuGe2-type phases occur as a second phase in mixtures with an AlB2-type phase. Diffraction of the x = 0.75(2) sample shows incommensurate modulation along the c direction; a structural model in super space group P31(00γ)00s reveals puckered 63 nets. Temperature-dependent magnetic susceptibility measurements for two AlB2-type compounds show Curie−Weiss behavior above 40.0(2) K and 45.5(2) K with magnetic moments of 7.98(1) μB for Eu(Zn0.48Ge0.52(2))2 and 7.96(1) μB for Eu(Zn0.30Ge0.70(2))2, respectively, indicating a (4f)7 electronic configuration for Eu atoms (Eu2+). The Zintl−Klemm formalism accounts for the lower limit of Ge content in the AlB2-type phases but does not identify the observed upper limit. In a companion paper, the intrinsic relationships among chemical structures, compositions, and electronic structures are analyzed by electronic structure calculations.

  • 668. Yukosawa, Tadahiro
    et al.
    Söderberg, Karin
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Boström, Magnus
    Grüner, Daniel
    Terasaki, Osamu
    Beyond the Traditional AB2 Laves Phase: Transmission Electron Microscopy StudyManuscript (Other academic)
  • 669.
    Zani, Lorenzo
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Eriksson, Lars
    Department of Physical, Inorganic and Structural Chemistry.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis of novel amino-acid-derived sulfinamides and their evaluation as ligands for the enantioselective transfer hydrogenation of ketones2008In: European Journal of Organic Chemistry, ISSN 1434-193X, no 27, p. 4655-4664Article in journal (Refereed)
  • 670. Zerbetto, Mirco
    et al.
    Polimeno, Antonino
    Kotsyubynskyy, Dmytro
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Ghalebani, Leila
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Kowalewski, Jozef
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry, Department of Physical Chemistry.
    Meirovitch, Eva
    Olsson, Ulrika
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    An integrated approach to NMR spin relaxation in flexible biomolecules: Application to β-D-glucopyranosyl-(1→6)-α-D-mannopyranosyl-OMe2009In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 131, no 23, p. p234501-Article in journal (Refereed)
    Abstract [en]

    The description of the reorientational dynamics of flexible molecules is a challenging task, in particular when the rates of internal and global motions are comparable. The commonly used simple mode-decoupling models are based on the assumption of statistical independence between these motions. This assumption is not valid when the time scale separation between their rates is small, a situation that was found to arise in oligosaccharides in the context of certain internal motions. To make possible the interpretation of NMR spin relaxation data from such molecules, we developed a comprehensive approach generally applicable to flexible rotators with one internal degree of freedom. This approach integrates a stochastic description of coupled global tumbling and internal torsional motion, quantum chemical calculations of the local potential and the local geometry at the site of the restricted torsion, and hydrodynamics-based calculations of the diffusive properties. The method is applied to the disaccharide -D-Glcp-(16)--D-[6-13C]-Manp-OMe dissolved in a DMSO-d6/D2O cryosolvent. The experimental NMR relaxation parameters, associated with the 13CH2 probe residing at the glycosidic linkage, include 13C T1 and T2 and 13C-{1H} nuclear Overhauser enhancement (NOE) as well as longitudinal and transverse dipole-dipole cross-correlated relaxation rates, acquired in the temperature range of 253–293 K. These data are predicted successfully by the new theory with only the H–C–H angle allowed to vary. Previous attempts to fit these data using mode-decoupling models failed.

  • 671. Zetterström, Per
    et al.
    Urbonaite, Sigita
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Lindberg, Fredrik
    Delaplane, R.G.
    Leis, Jaan
    Svensson, Gunnar
    Reverse Monte Carlo studies of nanoporous carbon from TiC2005In: Journal of Physics: Condensed Matter, ISSN 0953-8984, Vol. 17, p. 3509-3524Article in journal (Refereed)
  • 672.
    Zhang, Dong
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Johnsson, Mats
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Nickel vanadium tellurium oxide, NiV2Te2O102009In: Acta Crystallographica Section C: Crystal Structure Communications, ISSN 0108-2701, E-ISSN 1600-5759, Vol. 65, p. i9-i10Article in journal (Refereed)
    Abstract [en]

    Single crystals of a nickel vanadium tellurium oide were synthesized. The crystal structure is layered. The buliding units are VO~6~ octahedra and NiO~6~ octahedra and TeO~4~E distorted square pyramids (E being the 5s2^ lone-electron pair of Te^IV^).

  • 673.
    Zhang, Dong
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Johnsson, Mats
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Zn2(TeO3)Br22008In: Acta Crystallographica E, Vol. 64, p. i26-Article in journal (Refereed)
  • 674.
    Zhang, Dong
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Johnsson, Mats
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Berger, Helmuth
    Kremer, Reinhard K
    Separation of the oxide and halide part inthe oxohalide Fe3Te3O10Cl due to high Lewis acidity of the cations2009In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 48, p. 6599-6603Article in journal (Refereed)
    Abstract [en]

    crystallizes in the monoclinic space group P21/c. The crystal structure comprises channels where the Cl ions and also the stereochemically active lone-pair electrons on Te4+ are located. The Cl-atoms rather act as counter ions than being part of the covalent/ionic network. The magnetic susceptibility indicates antiferromagnetic ordering below TN~100 K with a marked splitting of the field cooled (fc) and the zero-field cooled (zfc) susceptibility at low magnetic fields; the splitting disappears at higher magnetic fields. Heat capacity measurements confirm the long range ordering at below this temperature. Only moderate shifts are observed with Raman spectroscopy at the magnetic transition

  • 675. Zhang, H.
    et al.
    Li, Z.C.
    Bergman, B.
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Investigation of La9.33Si6O26 oxygen ionic conductor2007In: Journal of Materials Science & Technology, Vol. 23, p. 629-632Article in journal (Refereed)
  • 676. Zhang, H. T.
    et al.
    Yan, Haixue
    Zhang, X. D
    Reece, Mike
    Liu, Jing Joan
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Shen, Zhijian
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Kan, Yanmei
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Wang, Peiling
    The effect of texture on the properties of Bi_3.15 Nd_0.85 Ti_3 O_12 ceramics prepared by Spark Plasma Sintering2007In: Materials Science and Engineering AArticle in journal (Refereed)
  • 677. Zhang, H.
    et al.
    Yu, T.
    Oleynikov, P.
    Zhao, D.Y.
    Hovmöller, Sven
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    CRISP and eMap: software for determining 3D pore structures of ordered mesoporous materials by electron crystallography2007In: | Recent Progress in Mesostructured Materials, Studies in Surface Science and Catalysis. Elsevier BV, no 165, p. 109-112Article in journal (Refereed)
  • 678. Zhang, H.
    et al.
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Oleynikov, Peter
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Hovmöller, Sven Erik
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Structure relations in real and reciprocal space of hexagonal phases related to i-ZnMgRE quasicrystals2006In: Philosophical Magazine, ISSN 1478-6435, E-ISSN 1478-6443, Vol. 86, no 3-5, p. 343-348Article in journal (Refereed)
    Abstract [en]

    The µ 3 , µ 5 and µ 7 approximants in Mg-Zn-RE were related in real and reciprocal space. The structure factors of µ 3 , µ 5 and µ 7 have quite similar intensity distributions and identical phases for the strongest corresponding reflections. Structure models of any of µ 3 , µ 5 and µ 7 can be obtained from any of the others using the strong reflections approach.

  • 679.
    Zhang, Hongqiang
    et al.
    Stockholm University, Faculty of Science, Department of Physics.
    He, Z.B.
    Oleynikov, Peter
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Hovmöller, Sven Erik
    Stockholm University, Faculty of Science, Department of Physics.
    Zou, X.D.
    Kuo, K.H.
    A structure model for τ(μ) phase in Al-Cr-Si alloys deduced from λ phase by the strong reflections approach2006In: Acta Crystallographica Section B: Structural Science, ISSN 0108-7681, E-ISSN 1600-5740, Vol. 62, no 1, p. 16-25Article in journal (Refereed)
    Abstract [en]

    There are very obvious common features in the electron diffraction patterns of the λ and τ(μ) phases in the Al–Cr–Si system. The positions of the strong reflections and their intensity distributions are similar for the two structures. The relation of the reciprocal lattices of the λ and τ(μ) phases is studied. By applying the strong-reflections approach, the structure factors of τ(μ) are deduced from the corresponding structure factors of the known λ phase. Rules for selecting reflections for the strong-reflections approach are described. Similar to that of λ, the structure of τ(μ) contains six layers stacked along the c axis in each unit cell. There are 752 atoms in each unit cell, 53 of them are unique. The corresponding composition of the τ(μ) model is Al3.82  −  xCrSix. Simulated electron diffraction patterns from the structure model are in good agreement with the experimental ones. The arrangement of interpenetrated icosahedral clusters in the τ(μ) phase is discussed.

  • 680. Zhang, Hongtao
    et al.
    Yan, Haixue
    Eriksson, Mirva
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Shen, Zhijian
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    The grain size effect on the properties of Aurivillius phase Bi3.15Nd0.85Ti3O12 ferroelectric ceramics2009In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 20, no 38, p. 385708/1-385708/5Article in journal (Refereed)
  • 681. Zhang, YF.
    et al.
    Li, YS.
    Sakamoto, Yasuhiro
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Che, S.
    Structure and thermal stability of mesostructured zirconium oxophosphates2007In: Microporous and mesoporous materials, Vol. 100, p. 295-301Article in journal (Refereed)
  • 682.
    Zhao, Gui-Ling
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Dziedzic, Pawel
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ullah, Farman
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Eriksson, Lars
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry, Department of Structural Chemistry.
    Córdova, Armando
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Organocatalytic enantioselective domino synthesis of highly functionalized cyclohexanes with an all-carbon quaternary stereocenter2009In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 50, no 26, p. 3458-3462Article in journal (Refereed)
    Abstract [en]

    A highly enantioselective organocatalytic domino Michael/aldol reaction is presented. The reaction is catalyzed by chiral amines and gives access to highly functionalized cyclohexanes with one all-carbon quaternary stereocenter and multiple chiral stereocenters in high yields and 83–98% ee.

  • 683.
    Zhao, Gui-Ling
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ullah, Farman
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Luca, Deiana
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lin, Shuangzheng
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zhang, Qiong
    Sun, Junliang
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry, Structural Chemistry.
    Ibrahem, Ismail
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Dziedzic, Pawel
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Córdova, Armando
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Dynamic kinetic asymmetric transformation (DYKAT) by combined amine- and transition-metal-catalyzed enantioselective cycloisomerization2010In: Chemistry: a European Journal, ISSN 0947-6539, Vol. 16, no 5, p. 1585-1591Article in journal (Refereed)
  • 684.
    Zhao, Gui-Ling
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Xu, Yongmei
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sundén, Henrik
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Eriksson, Lars
    Department of Physical, Inorganic and Structural Chemistry.
    Sayah, Mahmoud
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Córdova, Armando
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Organocatalytic enantioselective conjugate addition of aldehydes to maleimides2007In: Chemical Communications, p. 734-735Article in journal (Refereed)
  • 685.
    Zhao, Guoying
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Aziz, Baroz
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Hedin, Niklas
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Carbon dioxide adsorption on mesoporous silica surfaces containing amine-like motifs2010In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 87, no 9, p. 2907-2913Article in journal (Refereed)
    Abstract [en]

    The postcombustion separation of CO2 from a flue gas mixture is a unit operation in carbon capture. Today, CO2 is normally separated with alkanolamines in aqueous solutions. These absorption processes are energy intensive and costly. Increased environmental considerations and the significant footprints of many energy sources warrant the development of new gas separation techniques for the competitive implementation of carbon capture and storage technologies. Improved adsorbent-mediated separation processes are candidates for such new low-energy low-cost processes. In this study, porous silica-based adsorbents with amine-like motifs were synthesized. The temperature- and pressure-dependent adsorption of CO2 and CO2/H2O mixtures were determined and compared for these materials. The experimental uptake capacities of the materials modified with primary propyl amine moieties were significantly higher than those of materials modified with bis-ethanol amine or amidine. The propyl-amine-modified samples also showed good selectivity for CO2 over nitrogen gas.

  • 686.
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry, Structural Chemistry.
    3D structure determination from HRTEM and electron diffraction tomography2009Conference paper (Other (popular science, discussion, etc.))
  • 687.
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry, Structural Chemistry.
    3D Structure determination of novel porous materials by electron crystallography2009Other (Other academic)
  • 688.
    Zou, Xiaodong
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Conradsson, T.
    Christensen, Kirsten Elvira
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Ren, T.Z.
    O'Keeffe, M.
    Crystalline Micro- and Meso-porous Materials from Inorganic Molecular Clusters2007In: Recent Progress in Mesostructured Materials, Studies in Surface Science and Catalysis. Elsevier BV, Vol. 165, p. 173-176Article in journal (Refereed)
  • 689.
    Zou, Xiaodong
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Wan, Wei
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Hovmöller, Sven
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Quantitative 3D electron microscopy and 3D electron diffraction2010In: Journal of Chinese Electron Microscopy Society, Vol. 29, p. 230-243Article in journal (Refereed)
    Abstract [en]

    Electron crystallography can be used for determination of atomic structures of micrometer-/ nanometer-sized crystals, which are million times smaller than those required by X-ray crystallography. Structure determination at atomic resolution can be done from both high-resolution electron microscopy images combined with crystallographic image processing and electron diffraction data, or by combining them with powder X-ray diffraction data. Atoms may be overlapped in all projections if the unit cell of the crystal is large. In such cases, atomic structures can be obtained by collecting several diffraction patterns and images from different directions and combining them to reconstruct a three-dimensional potential map. In this paper, some recent developments of electron crystallography and its applications in structure determination of inorganic crystals in the past decade are shown.

     

  • 690. Zubkov, VG
    et al.
    Tyutyunnik, AP
    Tarakina, NV
    Svensson, Gunnar
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Forslund, Bertil
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Synthesis, crystal structure and luminescent properties of pyrovanadates A(2)CaV(2)O(7) (A = Rb, Cs)2009In: Solid State Sciences, ISSN 1293-2558, E-ISSN 1873-3085, Vol. 11, no 3, p. 726-732Article in journal (Refereed)
    Abstract [en]

    The novel vanadium oxides Rb2CaV2O7 and Cs2CaV2O7 have been prepared by solid-state reaction and their crystal structures determined and refined using X-ray, neutron powder and electron diffraction data. Rb2CaV2O7 and Cs2CaV2O7 are isostructural, crystallizing in space group P21/n with unit cell parameters: a = 13.8780(1), b = 5.96394(5), c = 10.3376(1) Å, ? = 104.960(1)º and a = 14.0713(2), b = 6.0934(1), c = 10.5944(1) Å, ? = 104.608(1)º, respectively. Their crystal structures can be described as a framework of CaO6 octahedra and V2O7 pyrogroups with alkaline metals found in the tunnels formed. Photoluminescence (PL) and PL excitation spectra of the concerned pyrovanadates have been studied in the vacuum ultraviolet (VUV) to visible light (VIS) range as well as their pulse cathode luminescence (PCL) spectra and the kinetic parameters of PCL. In the PL and the PCL spectra of both pyrovanadates recorded at T = 300 K a broad band with maxima at 2.38, 2.2 eV and a shoulder (band) at 2.08 eV have been observed. At T = 10 K the band at 2.08 eV becomes the main band in the spectra. Two types of luminescence centers for each pyrovanadates, with very similar excitation bands at 3.75, 4.84, 6.2, 7.3 and 9.1 eV, have been found. The nature of the luminescence centers connected with the band 2.08 eV (center I) and the bands 2.2 and 2.38 eV (center II) is discussed

  • 691. Öberg, Elisabet
    et al.
    Schäfer, Bernhard
    Geng, Xue-Li
    Pettersson, Jenny
    Hu, Qi
    Kritikos, Mikael
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Rasmussen, Torben
    Ott, Sascha
    C, C-Diacetylenic Phosphaalkenes as Heavy Diethynylethene Analogues2009In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 74, no 24, p. 9265-9273Article in journal (Refereed)
    Abstract [en]

    A series of C,C-diacetylenic phosphaalkenes 1be has been prepared from 1-chloropenta-1,2-dien-4-ynes 6be in a reaction with Mes*PCl2 (Mes* = 2,4,6-(tBu)3Ph) in the presence of LDA. Under identical conditions, isomeric butadiyne-substituted phosphaalkenes 2cf can be obtained from 3-chloropenta-1,4-diynes 5cf. The title compounds represent rare examples of diethynylethenes in which a constituting methylene has been replaced by a phosphorus center. The formation of both isomers can be rationalized by a common pathway that involves isomeric allenyllithium species. Spectroscopic, electrochemical, and theoretical investigations show that the phosphorus heteroatoms are an intrinsic part of the compounds’ π−systems and lead to decreased HOMO−LUMO gaps compared to those in all-carbon-based reference compounds.

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