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Orthorhombic System (orthorhombic + system)
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] Synthesis, Characterization and in Vitro Study of the Cytostatic and Antiviral Activity of New Polymeric Silver(I) Complexes with Ribbon Structures Derived from the Conjugated Heterocyclic Thioamide 2-Mercapto-3,4,5,6-tetra- hydropyrimidineEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 7 2004Panagiotis C. Zachariadis Abstract Silver(I) bromide reacts with 2-mercapto-3,4,5,6-tetrahydropyrimidine (StpmH2, C4H8N2S) in DMSO with an excess of triethylamine to give a water-insoluble complex of formula [Ag6(,2 -Br)6(,2 -StpmH2)4(,3 -StpmH2)2]n (1), while the reaction of silver(I) nitrate with StpmH2 under the same conditions gives a water-insoluble complex of formula [{Ag4(,2 -StpmH2)6}(NO3)4]n (2). The products were characterized by elemental analyses, and FT-IR far-IR, UV/Vis, 1H and 13C NMR spectroscopy. Crystal structures of complexes 1 and 2 were determined by X-ray diffraction. Complex 1, C24H48Ag6N12S6, crystallizes in the triclinic system space group P , a = 8.041(1) Å, b = 12.838(4) Å, c = 13.281(2) Å, , = 68.40(1)°, , = 72.97(1)°, , = 87.80(2), Z = 2, forming a one-dimensional infinite ribbon structure by strong interatomic interactions of two ,2 -Br bonds with Ag(1). Complex 2, C24H48Ag4N16O12S6, crystallizes in the orthorhombic system, space group Cmc21, and a = 32.148(3) Å, b = 9.461(2) Å, c = 7.234(1) Å, , = , = , = 90°, Z = 8, forming infinite Ag,S,Ag chains which are bridged to each other by a sulfur atom of ,2 -StpmH2 ligands. Complexes 1 and 2 were studied for their cytostatic activity against murine leukemia (L1210) and human T-lymphocyte (Molt4/C8 and CEM) cells and for their antiviral activity against a wide variety of viruses. They are markedly cytostatic at 50% inhibitory concentration (IC50) values ranging from 3 to 17 ,g/mL. None of the compounds showed appreciable antiviral activity at subtoxic concentrations. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Spectroscopic Investigation of the Europium(3+) Ion in a New ZnY4W3O16 MatrixHELVETICA CHIMICA ACTA, Issue 11 2009bieta Tomaszewicz Abstract A new Zn and Eu tungstate was characterized by spectroscopic techniques. This tungstate, of the formula ZnEu4W3O16, crystallized in the orthorhombic system and was synthesized by a solid-state reaction. It melts incongruently at 1330°. The luminescent properties, including excitation and emission processes, luminescent dynamics, and local environments of the Eu3+ ions in ZnEu4W3O16 and ZnY4W3O16,:,Eu3+ diluted phases (1, 5, and 10,mol-% of Eu3+ ion) were studied basing on the f6 -intraconfigurational transitions in the 250,720,nm spectral range. The excitation spectra of this system (,em 615 and 470,nm) show broad bands with maxima at 265 and 315,nm related to the ligand-to-metal charge-transfer (LMCT) states. The emission spectra under excitation at the O,W (265,nm) and O,Eu3+ (315,nm) LMCT states present the blue-green emission bands. The emission of tungstate groups mainly originate from the charge-transfer state of excited 2p orbitals of O2, to the empty orbitals of the central W6+ ions. On the other hand, in the emission of the Eu3+ ions, both the charge transfer from O2, to Eu3+ and the energy transfer from W6+ ions to Eu3+ are involved. The emission spectra under excitation at the 7F0,5L6 transition of the Eu3+ ion (394,nm) of ZnY4W3O16,:,Eu3+ diluted samples show narrow emission lines from the 5D3, 5D2, and 5D1 emitting states. The effect of the active-ion (Eu3+) concentration on the colorimetric characteristic of the emissions of the compound under investigation are presented. [source] Sildenafil citrate (Viagra) complexes with bivalent ionsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 1 2006Petr Melnikov Abstract The interaction of Ca2+ -ions with sildenafil citrate (Viagra) leads to the precipitation of a new polymorph variety of sildenafil base. Under the same conditions, Mg2+, Zn2+, and Cd2+ ions form structurally related crystalline complexes of the composition Me2+C28H34N6O11S. Lattice parameters have been determined showing that magnesium compound belongs to an orthorhombic system, while the zinc and cadmium compounds are its monoclinic distortions. All three compounds are thermally stable, undergoing decomposition above 175°C with the consequent formation of carbonates Me2+CO3 and oxides. © 2005 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 95:225,227, 2006 [source] Deficiency effects upon the physical properties of Pr0.8Sr0.2MnO3 manganite oxidePHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 9 2006W. Cheikh-Rouhou Koubaa Abstract The effects of deficiency in praseodymium and in strontium upon the magnetic and magneto-transport properties of lacunar Pr0.8,x,xSr0.2MnO3 and Pr0.8Sr0.2,x,x MnO3 oxides have been investigated. Our synthesized samples have been elaborated using the conventional solid state reaction at high temperature. Crystallographic studies show that all our samples are single phase and crystallize in the orthorhombic system with Pnma space group. The praseodymium deficient samples Pr0.8,x,xSr0.2MnO3 exhibit three different regimes in the resistivity variation as a function of praseodymium deficiency amount: (i) at low concentration (0 , x , 0.1), a semiconductor behaviour is observed in the whole temperature range, (ii) at an intermediate amount (x = 0.15), a semiconductor-metallic transition is followed by a metallic-semiconductor one with decreasing temperature, and finally (iii) at x = 0.2 and 0.25, a metallic behaviour is observed below TC, whereas all the strontium deficient samples exhibit a semiconductor behaviour in the whole temperature range. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] 1,1,-Fc(4-C6H4CO2Et)2 and its unusual salt derivative with Z, = 5, catena -[Na+]2[1,1,-Fc(4-C6H4CO2,)2]·0.6H2O [1,1,-Fc = (,5 -(C5H4)2Fe]ACTA CRYSTALLOGRAPHICA SECTION B, Issue 2 2010John F. Gallagher The neutral diethyl 4,4,-(ferrocene-1,1,-diyl)dibenzoate, Fe[,5 -(C5H4)(4-C6H4CO2Et)]2 (I), yields (II) (following base hydrolysis) as the unusual complex salt poly[disodium bis[diethyl 4,4,-(ferrocene-1,1,-diyl)dibenzoate] 0.6-hydrate] or [Na+]2[Fe{,5 -(C5H4)-4-C6H4CO}2]·0.6H2O with Z, = 5. Compound (I) crystallizes in the triclinic system, space group , with two molecules having similar geometry in the asymmetric unit (Z, = 2). The salt complex (II) crystallizes in the orthorhombic system, space group Pbca, with the asymmetric unit comprising poly[decasodium pentakis[diethyl 4,4,-(ferrocene-1,1,-diyl)dibenzoate] trihydrate] or [Na+]10[Fe{,5 -(C5H4)-4-C6H4CO}2]5·3H2O. The five independent 1,1,-Fc[(4-C6H4CO2),]2 dianions stack in an offset ladder (stepped) arrangement with the ten benzoates mutually oriented cisoid towards and bonded to a central layer comprising the ten Na+ ions and three water molecules [1,1,-Fc = ,5 -(C5H4)2Fe]. The five dianions differ in the cisoid orientations of their pendant benzoate groups, with four having their ,C6H4, groups mutually oriented at interplanar angles from 0.6,(3) to 3.2,(3)° (as ,..., stacked C6 rings) and interacting principally with Na+ ions. The fifth dianion is distorted and opens up to an unprecedented ,C6H4, interplanar angle of 18.6,(3)° through bending of the two 4-C6H4CO2 groups and with several ionic interactions involving the three water molecules (arranged as one-dimensional zigzag chains in the lattice). Overall packing comprises two-dimensional layers of Na+ cations coordinated mainly by the carboxylate O atoms, and one-dimensional water chains. The non-polar Fc(C6H4)2 groups are arranged perpendicular to the layers and mutually interlock through a series of efficient C,H..., stacking contacts in a herringbone fashion to produce an overall segregation of polar and non-polar entities. [source] A New Keggin Tungstocobaltate Decorated by Zinc(II) Complex Groups: [Zn(2,2,-bipy)3]3{[Zn(2,2,-bipy)2(H2O)]2 -[HCoW12O40]2}·H2OCHINESE JOURNAL OF CHEMISTRY, Issue 6 2009Hong WANG Abstract A new organic-inorganic hybrid compound based on Keggin tungstocobaltate decorated by zinc(II) coordination groups, [Zn(2,2,-bipy)3]3{[Zn(2,2,-bipy)2(H2O)]2[HCoW12O40]2}·H2O (bipy=bipyridine), has been synthesized under hydrothermal conditions and characterized by elemental analyses, IR, TG analyses and X-ray single crystal diffraction. This compound crystallizes in the orthorhombic system, space group C2/c with a=46.966(9) ?, b=14.358(3) Å, c=26.154(5) Å, ,=,=,=90°, V=17637(6) Å3, and Z=4. The result of structure determination shows that the crystal structure is constructed from a mono-supporting Keggin tungstocobaltate polyanion {[Zn(2,2,-bipy)2(H2O)]2[HCoW12O40]2}6,, three [Zn(2,2,-bipy)3]2+ cations and one water molecule. It is interesting that [Zn(1)(2,2,-bipy)3]2+ cations are held together into a helix chain through hydrogen-bonding interactions. Additionally, the compound is stable in air and shows intense photoluminescence at room temperature. [source] | |||||||||||||