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Cell Parameters (cell + parameter)
Kinds of Cell Parameters Selected AbstractsPowder second harmonic generation measurement and thermal decomposition mechanisms of a new organometallic compound [(18C6)Li][Cd(SCN)3]CRYSTAL RESEARCH AND TECHNOLOGY, Issue 9 2009J. J. Zhang Abstract Single crystals of a novel nonlinear optical organometallic compound CLTC, ([(18C6)Li][Cd(SCN)3]), were grown from aqueous solutions via evaporation technique and characterized by IR spectroscopy, thermal gravimetric analysis and X-ray single-crystal diffraction. By X-ray single-crystal structural analysis it is revealed that the compound crystallized in a noncentrosymmetric space group Cmc21 of orthorhombic system with cell parameter a = 14.767(3) Å, b = 15.454(3) Å, c = 10.644(2) Å, V = 2429.0(8) Å3 and Z = 4. The thermal stability and thermal decomposition of CLTC crystal were investigated by means of thermogravimetry and differential thermal analysis. The second harmonic generation (SHG) efficiency was measured using the Kurtz and Perry powder technique. It was shown that the value of the SHG efficiency of CLCT powder was about 2 times higher than that of potassium dihydrogen phosphate (KDP). (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Crystal structure of cobalt-substituted calcium hydroxyapatite nanopowders prepared by hydrothermal processingJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2010Ljiljana Veselinovi A series of cobalt-exchanged hydroxyapatite (CoHAp) powders with different Ca/Co ratios and nominal unit-cell contents Ca10,xCox(PO4)6(OH)2, x = 0, 0.5, 1.0, 1.5 and 2.0, were synthesized by hydrothermal treatment of a precipitate at 473,K for 8,h. Based on ICP (inductively coupled plasma) emission spectroscopy analysis, it was established that the maximum amount of cobalt incorporation saturated at ,12,at.% under these conditions. The effects of cobalt content on the CoHAp powders were investigated using ICP emission spectroscopy, particle size analysis, transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) analyses as well as X-ray powder diffraction (XRPD) including Rietveld analysis. According to XRPD, all the materials are single-phase HAp and CoHAp of low crystallinity. Rietveld analysis shows that Co enrichment causes the c cell parameter to decrease at a faster rate than the a cell parameter. A microstructural analysis showed anisotropic X-ray line broadening due to crystallite size reduction. In CoHAp there is significant crystal elongation in [001], and the average size decreases with increasing cobalt content. The crystallite morphology transforms from rod-like for the pure HAp to lamellae at the highest degree of Co substitution. The results of Rietveld refinement (symmetry, size and morphology of the crystallites) were confirmed by TEM and HRTEM analysis. [source] Negative (and very low) thermal expansion in ReO3 from 5 to 300,KJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2009Monica Dapiaggi This paper reports the accurate measurement of the ReO3 cell parameter as a function of temperature. The thermal expansion is confirmed to be negative over most of the temperature range from 5 to 300,K. The main problems with the measurements are the very small variations (in the range of 10,5,Å) in the cell parameter at each temperature, requiring tight control of the stability and reliability of instrumental effects. In particular, achieving monochromator stability over time might be challenging with the high energy and high beam current variations of a third-generation synchrotron facility. On the other hand, such effects are usually checked by the addition of silicon as an internal standard, but the accuracy (and precision) of the published thermal expansion (which is not certified) might not be sufficient for its use when dealing with very small cell parameter variations. [source] Synthesis and characterization of Cu3TaIn3Se7 and CuTa2InTe4PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2008P. Grima-Gallardo Abstract Polycrystalline samples of Cu3TaIn3Se7 and CuTa2InTe4 were synthesized by the usual melt and anneal technique. X-ray powder diffraction showed a single phase behavior for both samples with tetragonal symmetry and unit cell parameter values a = 5.794 ± 0.002 Å, c = 11.66 ± 0.01 Å, c /a = 2.01, V = 391 ± 1 Å3 and a = 6.193 ± 0.001 Å, c = 12.400 ± 0.002 Å, c /a = 2.00, V = 475 ± 1 Å3, respectively. Differential thermal analysis (DTA) measurements suggested a complicated behavior near the melting point with several thermal transitions observed in the heating and cooling runs. From the shape of the DTA peaks it was deduced that the melting is incongruent for both materials. Magnetic susceptibility measurements (zero-field cooling and field cooling) indicated an antiferromagnetic character with transition temperatures of T = 70 K (Cu3TaIn3Se7) and 42 K (CuTa2InTe4). A spin,glass transition was observed in Cu3TaIn3Se7 with Tf , 50 K. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Impact of ultraviolet radiation on HDPE and HDPE/STC blendsPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 3 2009Min Qiao Abstract The structure and properties of high-density polyethylene (HDPE) ultraviolet irradiated in ozone atmosphere were studied by FTIR, XPS, GPC, XRD, DSC, TG, gel, and contact angle test. The oxygen-containing groups such as CO, CO, and C(O)O were quickly introduced onto HDPE chains through ultraviolet irradiation in ozone atmosphere; their content increased with increase in the time of ultraviolet irradiation. Compared with those of HDPE, the molecular weight of the irradiated HDPE decreased and its distribution became wider. There was no gel in the HDPE irradiated in ozone atmosphere. After ultraviolet irradiation for short times in ozone atmosphere, the water contact angle of the irradiated HDPE decreased and its hydrophilicity was improved. The crystal shape of the irradiated HDPE was still an orthorhombic structure; its cell parameter and the face space did not alter, but its melting temperature decreased slightly. Compared with that of HDPE, the temperature of initial weight loss for irradiated HDPE decreased. The irradiated HDPE/sericite-tridymite-cristobalite (STC) blends were prepared. The dispersion and compatibility of the irradiated HDPE/STC blends were improved compared with those of HDPE/STC blends; thus its mechanical properties increased. Copyright © 2008 John Wiley & Sons, Ltd. [source] Comments on papers reporting IR-spectra and other data of alleged L-alanine alaninium nitrate and L-alanine sodium nitrate crystalsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 7 2009M. Fleck Abstract We argue that the IR- and Raman-spectra of "L-alanine alaninium nitrate" given in "Investigation on the growth, optical behaviour and factor group of an NLO crystal: L-Alanine Alaninium nitrate" by Aravindan et al., Cryst. Res. Technol. 42, 1097 (2007), actually concern L-Alanine. Correspondingly, the data presented in "A comparative study on the growth and characterization of nonlinear optical amino acid crystals: L-Alanine (LA) and L-alanine alaninium nitrate (LAAN)" by Aravindan et al., Spectrochim. Acta A 71, 297 (2008), seems to be erroneous, as is "Synthesis, Growth, and Characterization of a New Semiorganic Nonlinear Optical Crystal: L-Alanine Sodium Nitrate (LASN)", Sethuraman, et al., Cryst. Growth Des. 8, 1863 (2008). In these papers properties and data were reported for L-Alanine compounds that actually are L-Alanine crystals and, in addition, unit cell parameters were given that seem to have been copied from other papers. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Crystal structure characterization of the quaternary compounds CuFeAlSe3 and CuFeGaSe3CRYSTAL RESEARCH AND TECHNOLOGY, Issue 5 2009G. E. Delgado Abstract The crystal structure of the chalcogenide compounds CuFeAlSe3 and CuFeGaSe3, belonging to the system I-II-III-III3, were characterized using X-ray powder diffraction data. Both compounds crystallize in the tetragonal space group P42c (N° 112), Z = 1, with unit cell parameters a = 5.609(1) Å, c = 10.963(2) Å for CuFeAlSe3 and a = 5.6165(3) Å, c = 11.075(1) Å for CuFeGaSe3. These compounds are isostructural with CuFeInSe3, and have a normal adamantane structure. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Structural study of the semimagnetic semiconductor Zn0.5Mn0.5In2Te4CRYSTAL RESEARCH AND TECHNOLOGY, Issue 2 2009G. E. Delgado Abstract The semimagnetic semiconductor alloy Zn0.5Mn0.5In2Te4 was refined from an X-ray powder diffraction pattern using the Rietveld method. This compound crystallizes in the space group I42m (Nº 121), Z = 2, with unit cell parameters a = 6.1738(1) Å, c = 12.3572(4) Å, V = 471.00(2) Å3, c/a = 2.00. This material crystallizes in a stannite-type structure. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Synthesis, crystal structure and vibrational characterization of bis-,-peroxo-hexacarbonatodicerate(IV) complexes of rubidium and cesiumCRYSTAL RESEARCH AND TECHNOLOGY, Issue 11 2008N.-P. Pook Abstract The new compounds Rb8[Ce(O2)(CO3)3]2 · 12 H2O (1) and Cs8[Ce(O2)(CO3)3]2 · 10 H2O (2) were obtained from the reaction of hydrogen peroxide and Ce(III) in saturated alkali carbonate solutions. The crystal structures and the unit cell parameters of (1) triclinic, P-1 with a = 8.973(2) Å, b = 10.815(2) Å, c = 11.130(3) Å, , = 66.992(2)°, , = 68.337(2)°, , = 74.639(2)°, VEZ = 914.7(4) Å3, Z = 2, and (2) orthorhombic, Pbca, a = 19.3840(16) Å, b = 18.528(2) Å, c = 10.487(3) Å, VEZ = 3766.4(13) Å3, Z = 8, were determined. Both compounds contain the bis-µ-peroxo-hexacarbonatodicerate(IV)-ion, [(CO3)3Ce(O2)2Ce(CO3)3]8- . IR and Raman spectra were measured and discussed. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Crystal structure of a ternary mononuclear copper (II) complex: 4-chloro-3-methyl-6[(N-2-picolyl)-1,-iminomethyl]phenolato copper(II)perchlorateCRYSTAL RESEARCH AND TECHNOLOGY, Issue 5 2006S. M. Malathy Sony Abstract The complex crystallizes in monoclinic space group P21/n with unit cell parameters a = 7.295(4), b = 19.627(5), c = 12.770(4) Å, , = 101.25(4)º, V = 1793.2(12) Å3, Z = 4, , = 1.684 Mg/m3 at T = 293(2)K. The structure was solved by Patterson method and refined by full-matrix least-squares procedures to final R = 0.0387 using 2906 observed reflections. The asymmetric unit of the complex contains a mononuclear tridentate ligand, a perchlorate group and a methanol molecule. The compound crystallizes as parallel layers of polymeric complex bridged through perchloarate groups. The molecular CuN2OO,O,,2 chromophore involves an elongated rhombic octahedral structure and the Cu-ligand bond shows greater disparity. The five-membered chelate ring and the pyridine ring lie in the same plane while the six membered chelate ring assumes sofa conformation. A strong O-H,O inter molecular interaction plays a key role in the formation of dimer along b-axis. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Synthesis and structural conformation of N-substituted 1,4-dihyropyridine derivativesCRYSTAL RESEARCH AND TECHNOLOGY, Issue 1 2006M. Mahendra Abstract N-(Phenyl)-3,5-dicarbethoxy-2,6-dimethyl-4-(phenyl)-1,4-dihydropyridine (A) and N-(4-methoxy phenyl)--3,5 dicarbethoxy-2,6 dimethyl-4-(3-nitro phenyl)-1,4-dihydropyridine (B) has been synthesized as per scheme and characterized by the X-ray diffraction method. The compound A crystallizes in monoclinic space group P21/c with cell parameters a = 9.2770(11)Å, b = 8.6410(5)Å, c = 27.601(3)Å, , = 97.724(3)°, Z = 4. The compound B crystallizes in monoclinic space group P21/c with cell parameters a = 11.229(6), b = 12.746(7)Å, c =17.606(6)Å, , = 104.531(3)°, Z = 4. The structures exhibit both intra and intermolecular hydrogen bonds. Dihydropyridine ring of both the compounds adopt a flat boat conformation. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Synthesis, structural and thermal studies of tetrathioureacopper(I) chloride crystalsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 8 2005M. Dhandapani Abstract Tetrathioureacopper(I) chloride, hereafter abbreviated as TCC, was synthesised and single crystals were obtained from saturated aqueous solution by slow evaporation (solution growth) method at room temperature. The crystals obtained are bright, colourless and transparent having well defined external faces. The grown crystals were characterized through elemental analysis, single crystal X-ray diffraction study, thermal analysis, electron spin resonance spectroscopy and Fourier Transform infrared spectroscopy. The elemental analysis confirms the stoichiometry of the compound. The single crystal diffraction studies indicate that TCC crystallises in the tetragonal lattice and the unit cell parameters are a = b = 13.4082 Å, c = 13.8074 Å, V = 2482.29 Å3, , = , = , = 90°. Space group and the number of molecules per unit cell (Z) are found to be P41212 and 8 respectively. The TG curve of the sample shows a prolonged decomposition from 210 to 628.3 °C, from which the decomposition pattern has been formulated. The endothermic peaks in the DTA curve indicate melting and decomposition of the compound at 165.2 and 633.8 °C respectively. An exothermic peak in high temperature DSC indicates a phase transition in the compound at 274.8 °C. Thermal anomalies observed in the low temperature DSC at ,163.3, ,152.0, ,141.5, ,108.3, 1.0 and 12.1 °C in the heating run and ,157.1 and ,153.9 °C in the cooling run reveal first order phase transitions in the crystal. The peaks observed at ,146.2 °C in both the heating and cooling runs suggest occurrence of a second order phase transition in this compound. The IR spectroscopic data were used to assign the characteristic vibrational frequencies of various groups present in the compound. The ESR study confirms that the copper is in the +1 oxidation state in the complex. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Crystal structure of N-[(1Z)-1-(3-methyl-3-phenylcyclobutyl)-2-thiomorpholin-4-ylethylidene] thioureaCRYSTAL RESEARCH AND TECHNOLOGY, Issue 7 2005U. Sar Abstract The crystal structure of N-[(1Z)-1-(3-methyl-3-phenylcyclobutyl)-2-thiomorpholin-4-ylethylidene] thiourea (C18H26N4S2) has been determined by X-ray crystallographic techniques. The compound crystallizes in the orthorhombic space group Pbca, with unit cell parameters: a = 15.692(3), b = 20.803(8), c = 11.979(6)Å, Z = 8, V = 3911(7)Å3. The crystal structure was solved by direct methods and refined by full-matrix least squares to a final R-value of 0.084 for 1447 observed reflections [I > 2, ( I ) ]. In the thiosemicarbazide moiety, the S = C bond length is 1.656(6), N-C-N angle is 115.6(5)°. The crystal structure is stabilized by the intermolecular N-H...S hydrogen bonds. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Growth and characterization of undoped, Sr2+ -, and Mn2+ -doped ammonium tetrachlorozincateCRYSTAL RESEARCH AND TECHNOLOGY, Issue 3 2005M. A. Gaffar Abstract Crystals of ammonium tetrachlorozincate (AZC) undoped and doped with Sr2+ or Mn2+ in different concentrations were grown by the slow evaporation method from an aqueous solution. The crystal morphology changed considerably by doping. The dopant concentration in the crystals was measured by the atomic absorption technique. Slight changes in the unit cell parameters of AZC after doping with Sr2+ - or Mn2+ have been detected. Optical absorption measurements indicated strong influence of Sr2+ and Mn2+ doping. The optical energy gap at room temperature decreased continuously with increasing Sr2+ and Mn2+ concentration but with two different rates. The dc conductivity was also measured as a function of temperature for the undoped and two samples doped with 0.144 Sr2+ and 0.191 Mn2+ and the results were compared. Positions possibly occupied by Sr2+ and Mn2+ cations in AZC lattice have been identified. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Structure, growth and optical properties of Zn0.24Ni0.76(SO4)·7H2O single crystalCRYSTAL RESEARCH AND TECHNOLOGY, Issue 9 2004Xinxin Zhuang Abstract A new crystalline complex zinc nickel sulfate heptahydrate (ZNSH) has been prepared. The crystal structure was investigated by x-ray single crystal diffraction method and the empirical formula is Zn0.24Ni0.76(SO4)·7H2O. The ZNSH crystal belongs to the orthorhombic space group P212121 with cell parameters a = 6.7742(14) Å, b = 11.748(2) Å, c = 12.009(2) Å. The deep-green ZNSH single crystal with dimension of 30 × 25 × 25 mm3 has been grown by the cooling solution method. The constituent ratio of ZNSH crystal grown from various compounding solutions at temperature range 40-50 °C is approximate invariant. The crystal absorption spectra with theoretical analysis are reported. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Ca for Er substitution in tetragonal ErPO4 · H2O crystallised from phosphoric acid solutionCRYSTAL RESEARCH AND TECHNOLOGY, Issue 2 2004R. Kijkowska Abstract Erbium phosphate monohydrate with limited Ca for Er substitution, obtained through crystallisation from boiling phosphoric acid solution has been characterised by X-ray diffraction, Ir-spectroscopy and thermal analysis (TGA-DTA) methods. The difference in the electric charge between di-valent calcium and tri-valent erbium in the solid crystallised was compensated by simultaneous substitution of HPO42- for PO43- . Ca incorporation in erbium phosphate made expansion of tetragonal ErPO4 · H2O unit cell. After ignition at 900 °C the tetragonal crystal modification was maintained but the unit cell parameters of all the investigated phosphates, whether Ca-substituted or Ca-free, contracted to the same level. The unique contraction of the unit cell was resulted from recrystallisation of Ca-substituted into Ca-free erbium phosphate, while Ca was transferred into Ca(PO3)2 formed as a separate phase. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Structure and conformation of a nickel complex: {2-Hydroxo-3-piperidine-1-yl-methyl-N,N,(bis-5-bromobenzylpropylenediimine)nickel(II)perchlorate}CRYSTAL RESEARCH AND TECHNOLOGY, Issue 2 2004S. M. Malathy Sony Abstract The title compound, a nickel complex [C23H26N3O2Br2Ni.(ClO4)] (CCDC 199520) crystallizes in triclinic space group P with the cell parameters a = 10.2560(4), b = 10.8231(4), c = 12.0888(5)Å, , = 99.404(1), , = 99.780(1), , = 92.252(1)° and V = 1301.49(9)Å3. The structure was solved by Patterson method and refined by full-matrix least-squares procedures to a final R = 0.0497 using 6287 observed reflections. In the complex, the piperidine ring takes chair conformation and the geometry around the Ni ion is slightly distorted square planar. The dihedral angle between the planes [N-Ni-N and O-Ni-O] is 9.4(1)°. The chelate ring containing both the nitrogen atoms adopts twisted boat conformation. The molecules in the crystal are stabilized by N-H,O and C-H,O types of hydrogen bonds in addition to a C-H,, interaction. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Crystal structure of ,-phenoxo bridged dicopper complex: {N-[(2-hydroxylato-5-methyl)benzyl-(2,-hydroxylato-3,,5,-dimethylbenzyl)]ethyl amine dicopper(II)}CRYSTAL RESEARCH AND TECHNOLOGY, Issue 12 2002S. M. Malathy Sony Abstract The title compound crystallizes in monoclinic space group C2/c with cell parameters a = 21.404(2), b = 13.962(1), c = 17.917(1)Å, , = 124.394(2)°, V = 4418.3(6)Å3, Z = 8, Dcal = 1.193Mg/m3 and T = 293 K. The structure was solved by Patterson method and refined by full-matrix least-squares procedures to final R = 0.0882 using 5253 observed reflections. The tetra coordinated copper atom have a slight distorted square planar geometry with the Cu-Cu distance of 2.987(1)Å. The two six membered rings containing copper atom assume distorted sofa conformation. C-H,, and C-H,O type of intermolecular interactions play a role in stabilizing the crystal packing in addition to van der Waals forces. [source] Changes in murine bone marrow macrophages and erythroid burst-forming cells following the intravenous injection of liposome-encapsulated dichloromethylene diphosphonate (Cl2MDP)EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 4 2001A. L. Giuliani Abstract: In order to explore the effect on bone marrow macrophages of liposome-encapsulated dichloromethylene diphosphonate (Cl2MDP), mice were injected intravenously with a preparation of such liposomes at a dose known to deplete spleen and liver macrophages. Two days later, the macrophages in the marrow of the femoral bones were quantified by flow cytometry using a macrophage-specific monoclonal antibody (F4/80), and their ultrastructure and phagocytic activity towards zymosan particles was assessed. To determine the effect on erythropoiesis of liposome-encapsulated Cl2MDP-induced changes in bone marrow macrophages, red blood cell parameters and the formation of erythroid burst-forming unit (BFU-E)-derived colonies in vitro were evaluated. In mice injected with liposome-encapsulated Cl2MDP, there was a 54% and 67% decrease in the total number of bone marrow macrophages as compared to uninjected controls and mice treated with empty liposomes, respectively. Moreover, residual macrophages showed an abnormal ultrastructure, with reduced numbers of crystalloid inclusions and increased numbers of large myelin figures. However, the phagocytic activity of these cells was unimpaired or slightly enhanced. In mice injected with liposome-encapsulated Cl2MDP there was an approximately 60% decrease in the percentage and total number of circulating reticulocytes and a 54% reduction in the BFU-E number, demonstrating deregulation of erythropoiesis under conditions of macrophage loss and impairment. The results suggest that mice treated with liposome-encapsulated Cl2MDP are a model for studying the role of macrophages in erythropoiesis. [source] Mu-35: A Fluorogallophosphate Obtained by In Situ Generation of the TemplateEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 25 2007Louwanda Lakiss Abstract A two-dimensional microporous fluorogallophosphate, named Mu-35, closely related to ULM-8, was hydrothermally synthesized by in situ generation of the structure-directing agent. The precursor of the structure-directing agent is ethylformamide, which is generated in situ by decomposition, and goes on to form ethylamine molecules that act as templates in the medium used for the synthesis. The fluorogallophosphate Mu-35 (Mu is Mulhouse), Ga3(PO4)2(HPO4)F3(C2H8N)2(C2H7N)0.5 (Z = 8), crystallizes in the orthorhombic space group Pbcn with the following unit cell parameters: a = 22.117(1), b = 17.3740(8), c = 10.1550(4) Å. The structure of fluorogallophosphate Mu-35 was determined from single-crystal XRD data. It exhibits anionic layers composed of an unusual arrangement of three-, five-, and eight-membered rings (MR) [Ga2PO2F, Ga3P2O4F, and Ga3P3O8, respectively], and intercalated by protonated and nonprotonated ethylamine molecules. Mu-35 was also characterized by powder XRD, SEM, elemental and thermal analyses, and solid-state NMR spectroscopy (1H, 13C, 19F, and 31P MAS and 1H- 31P HETCOR experiments). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] One-Dimensional Oxalato-Bridged Metal(II) Complexes with 4 - Amino-1,2,4-triazole as Apical LigandEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 21 2005Urko García-Couceiro Abstract The synthesis, chemical characterization, thermal behavior and magnetic properties of six new one-dimensional oxalato-bridged metal(II) complexes of formula [M(,-ox)(4atr)2]n [MII = Cu (1), Ni (2), Co (3), Zn (4), Fe(5)] and [Cd(,-ox)(4atr)2(H2O)]n (6) (ox = oxalato dianion, 4atr = 4-amino-1,2,4-triazole) are reported. The crystal structures of 1 and 6 have been solved by single-crystal X-ray diffraction, whereas the remaining compounds have been studied by means of X-ray powder diffraction methods. Compounds 1,5 are isomorphous and crystallize in the triclinic space group P1¯ with unit cell parameters for 1 of a = 5.538(1) Å, b = 7.663(1) Å, c = 7.711(2) Å, , = 62.21(1)°, , = 73.91(1)°, , = 86.11(1)°, and Z = 1. The crystal structures are comprised of one-dimensional linear chains in which the trans -[M(4atr)2]2+ units are sequentially bridged by bis(bidentate) oxalato ligands, resulting in an octahedral O4N2 donor set. Cryomagnetic susceptibility measurements show the occurrence of antiferromagnetic intrachain interactions for 2, 3, and 5, whereas compound 1 exhibits a weak ferromagnetic coupling in agreement with the out-of-plane exchange pathway involved. The magnetic behavior of 1 and 2 is analyzed and discussed in the light of the available magneto-structural data for analogous systems. CdII complex crystallizes in the monoclinic space group C2/c with unit cell parameters of a = 16.128(2) Å, b = 6.757(1) Å, c = 11.580(2) Å, , = 104.46(1)°, and Z = 4. Its crystal structure contains one-dimensional chains in which metal centers are heptacoodinated to four oxygen atoms from two symmetry-related bis(bidentate) oxalato bridges, two endocyclic nitrogen atoms of trans -coordinated triazole ligands and one water molecule, to give a CdO4OwN2 pentagonal-bipyramidal geometry. Thermoanalytical and variable-temperature X-ray powder diffraction analyzes show that compound 6 undergoes a reversible dehydration,hydration process in which the anhydrous residue crystallizes with a different crystal lattice retaining the dimensionality of the oxalato,metal framework. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Material Solubility-Photovoltaic Performance Relationship in the Design of Novel Fullerene Derivatives for Bulk Heterojunction Solar CellsADVANCED FUNCTIONAL MATERIALS, Issue 5 2009Pavel A. Troshin Abstract The preparation of 27 different derivatives of C60 and C70 fullerenes possessing various aryl (heteroaryl) and/or alkyl groups that are appended to the fullerene cage via a cyclopropane moiety and their use in bulk heterojunction polymer solar cells is reported. It is shown that even slight variations in the molecular structure of a compound can cause a significant change in its physical properties, in particular its solubility in organic solvents. Furthermore, the solubility of a fullerene derivative strongly affects the morphology of its composite with poly(3-hexylthiophene), which is commonly used as active material in bulk heterojunction organic solar cells. As a consequence, the solar cell parameters strongly depend on the structure and the properties of the fullerene-based material. The power conversion efficiencies for solar cells comprising these fullerene derivatives range from negligibly low (0.02%) to considerably high (4.1%) values. The analysis of extensive sets of experimental data reveals a general dependence of all solar cell parameters on the solubility of the fullerene derivative used as acceptor component in the photoactive layer of an organic solar cell. It is concluded that the best material combinations are those where donor and acceptor components are of similar and sufficiently high solubility in the solvent used for the deposition of the active layer. [source] Plastic Solar Cells Based on Fluorenone-Containing Oligomers and Regioregular Alternate Copolymers,ADVANCED FUNCTIONAL MATERIALS, Issue 9 2005R. Demadrille Abstract Oligomers and regioregular copolymers based on fluorenone subunits are synthesized and used in bulk-heterojunction photovoltaic cells. These are 2,7-bis(5-[(E)-1,2-bis(3-octylthien-2-yl)ethylene])-fluoren-9-one (TVF), the product of its oxidative polymerization, that is, (poly[(5,5,-(bis-(E)-1,2-bis(3-octylthien-2-yl)ethylene]- alt -(2,7-fluoren-9-one)]) (PTVF), and an alternate copolymer of fluoren-9-one and di- n -alkylbithiophene, namely poly[(5,5,-(3,3,-di- n -octyl-2,2,-bithiophene))- alt -(2,7-fluoren-9-one)] (PDOBTF). The interpenetrating networks of active layers consisting of these new compounds as electron donors and of methanofullerene [6,6]-phenyl-C61 -butyric acid methyl ester (PCBM) as an acceptor exhibit an extended absorption band in the visible part of the spectrum with an absorption edge close to 700,nm. The external power conversion efficiencies (EPCEs) and the external quantum efficiency of the various TVF-, PTVF-, and PDOBTF-based photovoltaic cells have been determined. EPCE values of up to 1,% have been achieved, which demonstrate the potential of fluorenone-based materials in solar cells. It has also been demonstrated that fluorenone subunits are efficient photon absorbers for the conversion. Interestingly, some cell parameters such as, for example, the fill factor, have been improved as compared to photovoltaic cells with a "classical" poly[2-methoxy-5-(3,,7,-dimethyloctyloxy)-1,4-phenylenevinylene]/PCBM active layer, fabricated and studied under the same experimental conditions. [source] Respiratory changes in human red cellsINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 6 2001G. Aliberti To investigate physiological respiratory changes in human red cells, we measured automated red cell parameters in samples from the pulmonary and radial arteries of 86 patients undergoing aorto-coronary bypass and from the pulmonary artery and the aorta in 23 patients. Our results showed higher mean corpuscular volume (88.53 ± 5.06 fl vs. 88.12 ± 4.94 fl, P < 0.000001), haematocrit (0.369 ± 0.039 vs. 0.367 ± 0.038, P < 0.0005), red cell distribution width (43.38 ± 4.16 vs. 43.04 ± 4.05 fl, P < 0.000001) and a lower mean corpuscular haemoglobin concentration (338.3 ± 15.9 vs. 339.9 ± 16.8 g/l, P < 0.005) in pulmonary arterial as compared to radial arterial blood. There were no differences with respect to haemoglobin concentration, red blood cell count, or mean corpuscular haemoglobin. Similar differences were observed between pulmonary arterial and aortic blood. Our results suggest cyclic respiratory modifications of red cell parameters attributable to the CO2 Jacobs,Stewart cycle. [source] Structural study of monoclinic KGd(WO4)2 and effects of lanthanide substitutionJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 1 2001M. C. Pujol The crystal structure of monoclinic KGd(WO4)2 (KGW) has been refined at room temperature by using single-crystal X-ray diffraction data. The unit-cell parameters are a = 10.652,(4), b = 10.374,(6), c = 7.582,(2),Å, , = 130.80,(2)°, with Z = 4, in space group C2/c. The linear thermal expansion tensor has been determined and the principal axes are [302], [010] and [106]. The principal axis with maximum thermal expansion ( = 23.44 × 10,6,K,1), , was located 12° from the c axis. Undoped crystals of KGW and crystals that were partially doped by Pr, Nd, Ho, Er, Tm and Yb were grown by the top-seeding-solution growth slow-cooling method. The effect of doping on the KGW structure was observed in the cell parameters and in morphological changes. The changes in parameters follow the changes in lanthanide ionic radii. The doped crystals show {021} and {21} faces in addition to the {110}, {11}, {010}, {130} and {310} faces which basically follow the habit of the undoped KGW crystals. The development of the faces is related to the number of the most important periodic bond chains parallel to them. [source] Synthesis of processible doped polyaniline-polyacrylic acid compositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2009Bhavana Gupta Abstract Processible composites of emeraldine salt form of polyaniline (PANI) with polyacrylic acid (PAA) are synthesized and studied for their structural, electrical, mechanical, thermal, and electrochemical properties. The processible conducting composites of various weight percentage from 20 wt % to 90 wt % (of PANI) have been prepared by mixing the PANI and PAA under vigorous stirring and sonication conditions. Self-standing films of electroactive homogeneous composites are obtained by solution casting method. A significant improvement in processibility, crystallinity, and thermal stability is observed in the composites; however, the electrical conductivity decreased remarkably as the percentage of PANI is decreased in the composites. The 60 wt % PANI-PAA composite showed crystalline structural property with orthorhombic crystal system and cell parameters as a = 5.93Å, b = 7.57Å, and c = 10.11Å. The 60 wt % PANI-PAA composite also showed better thermal stability and highest capacitance amongst all the composites and used as an active material for development of electrochemical capacitors (parallel plate assembly). The processible composites based electrochemical capacitors using 0.5 M NaClO4 -Acetonitril electrolyte showed super capacitance with ease in fabrication and cost effectiveness in comparison to other similar materials based capacitors. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Cell morphology and intracellular ionic homeostasis explored with a multimodal approach combining epifluorescence and digital holographic microscopyJOURNAL OF BIOPHOTONICS, Issue 7 2010Nicolas Pavillon Abstract The authors have developed a live-cell multimodality microscope combining epifluorescence with digital holographic microscopy; it has been implemented with a decoupling procedure allowing to separately measure from the quantitative phase important cell parameters including absolute volume, shape and integral intracellular refractive index. In combination with the numerous different specific fluorescent cellular probes, this multimodality microscopy can address important issues in cell biology. This is demonstrated by the study of intracellular calcium homeostasis associated with the change in cell volume, which play a critical role in the excitotoxicity-induced neuronal death. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] On the Crystal Structure of Isotactic cis -1,4-Poly(1,3-pentadiene)MACROMOLECULAR THEORY AND SIMULATIONS, Issue 8 2006Roberto Napolitano Abstract Summary: A comparison between the crystal structure of isotactic cis -1,4-poly(1,3-pentadiene) previously predicted by molecular mechanics calculations and that successively determined by other authors by experimental data is reported. The agreement between the two structures is very good as far as the space group, the unit cell parameters and the conformation of the polymer chain are concerned. The mode of packing of the chains proposed in the experimental crystal structure is very similar to that found as relative minimum in the previous energy calculations. The coexistence, in different amounts, of these two modes of packing is suggested by the analysis of the simulated X-ray spectra and by the results of new energy calculations. A mode of packing of chains of isotactic cis -1,4-poly(1,3-pentadiene). [source] Investigation of structure and dynamics in the sodium metallocenes CpNa and CpNa·THF via solid-state NMR, X-ray diffraction and computational modellingMAGNETIC RESONANCE IN CHEMISTRY, Issue S1 2007Cory M. Widdifield Abstract Solid-state 23Na NMR spectra of two organometallic complexes, cyclopentadienylsodium (CpNa) and the tetrahydrofuran (THF) solvate of CpNa (CpNa·THF), are presented. Analytical simulations of experimental spectra and calculated 23Na electric-field gradient (EFG) tensors confirm that both complexes are present in microcrystalline samples of CpNa recrystallized from THF. For the solvate, 23Na NMR experiments at 9.4 T and 11.7 T elucidate sodium chemical shielding (CS) tensor parameters, and establish that the EFG and CS tensor frames are non-coincident. Single-crystal X-ray diffraction (XRD) experiments are used to determine the crystal structure of CpNa·THF: Cmca (a = 9.3242(15) Å, b = 20.611(3) Å, c = 9.8236(14) Å, , = , = , = 90° , V = 1887.9(5)Å3, Z = 8). For CpNa, 23Na NMR data acquired at multiple field strengths establish sodium CS tensor parameters more precisely than in previous reports. Variable-temperature (VT) powder XRD (pXRD) experiments determine the temperature dependence of the CpNa unit cell parameters. The combination of 23Na quadrupolar NMR parameters, pXRD data and calculations of 23Na EFG tensors is used to examine various models of dynamic motion in the solid state. It is proposed that the sodium atom in CpNa undergoes an anisotropic, temperature-dependent, low frequency motion within the ab crystallographic plane, in contrast with previous models. Copyright © 2007 John Wiley & Sons, Ltd. [source] Crystal structure of the new quaternary copper manganese and zirconium chalcogenidesPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 4 2007V. P. Sachanyuk Abstract The compounds Cu2MnZrS4 and Cu2MnZrSe4 were obtained by solid-state synthesis method. It was established using an XRD powder method that they crystallize in the hexagonal structural type (space group P3m1) with unit cell parameters a = 0.37427(2) nm, c = 0.61004(3) nm (Cu2MnZrS4); a = 0.39085(2) nm, c = 0.63709(3) nm (Cu2MnZrSe4). Atomic parameters were calculated using the anisotropic approximation (RI = 0.0523 and RI = 0.0473 for Cu2MnZrS4 and Cu2MnZrSe4, respectively). (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||||||||||||||||||||