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Bustos C.,Austral University of Chile | Alvarez-Thon L.,Andrés Bello University | Carcamo J.-G.,Austral University of Chile | Ibaez A.,Laboratorio Of Cristalografia | Sanchez C.,Austral University of Chile
Acta Crystallographica Section E: Structure Reports Online | Year: 2011

The mol-ecular structure of the title compound, C21H 15ClN2O2, features one strong intra-molecular N - H⋯O resonance-assisted hydrogen bond (RAHB). In the crystal, mol-ecules form inversion-related dimers via pairs of weak inter-molecular N - H⋯O contacts. These dimers are further stabilized via three weak C - H⋯O contacts, developing the three-dimensional structure.


Pena-Pedraza H.,University of Pamplona | Lopez-Rivera S.A.,Laboratorio Of Fisica Aplicada | Martin J.M.,Laboratorio Of Fisica Aplicada | Delgado J.M.,Laboratorio Of Cristalografia
Materials Science and Engineering B: Solid-State Materials for Advanced Technology | Year: 2012

Using single-crystal X-ray diffraction and Raman spectroscopy, the characterization of a member of the II-IV-V 2 family of semiconducting compounds, ZnSiP 2, is presented in this work. The diffraction experiment showed that ZnSiP 2 crystallizes in a chalcopyrite-type of structure (space group: I4̄2d) with unit cell parameters a = 5.407(9) and c = 10.454(2) . The structure is based on a cubic close-packed arrangement of phosphorus atoms with the two cations in an orderly way occupying one-half of the tetrahedral sites. In this structure, two Zn and two Si are bonded to each phosphorus atom and four phosphorus atoms are bonded to each cation. The results obtained are consistent with previous reports. Raman spectroscopy, Group Theory, and a modified correlation method allowed the assignment of the characteristics of the thirteen first-order Raman active optical vibrational modes observed for this material. © 2011 Elsevier B.V.


Torres J.,Catedra de Quimica Inorganica | Morales P.,Catedra de Quimica Inorganica | Dominguez S.,University of La Laguna | Gonzalez-Platas J.,University of La Laguna | And 4 more authors.
Journal of Molecular Structure | Year: 2011

The stoichiometric reaction of copper(II) chloride with iminodiacetic acid (H2ida), and lanthanide(III) chloride in water yields the heteropolynuclear complexes [Ln2Cu3(ida) 6]·xH2O. In this work, the synthesis and full characterization of those complexes with Ln = Ce, Ho is presented. The structures are based on [Cu(ida)2] building blocks, linked by the Ln ions via carboxylate bridges. The formation of nanochannels along the crystallographic c axis is verified. The comparison with analogous complexes containing other Ln ions, shows that the channels are perfectly tuneable in size along the series. These chemical systems were also investigated in solution (25.0 °C, I = 0.5 M Me4NCl) by potentiometry. The same kind of polynuclear species have been found in aqueous solution. © 2011 Elsevier B.V. All rights reserved.


Pintos V.,Catedra de Quimica Inorganica | Cuevas A.,Catedra de Quimica Inorganica | Onetto S.,University of the Republic of Uruguay | Seoane G.,University of the Republic of Uruguay | And 5 more authors.
Journal of Molecular Structure | Year: 2010

The azine bridged dicatechol ligand (E,E)-benzaldehyde azine (H4L) was fully characterized by X-ray analysis. The reaction of [ReCl6]2- with this compound was studied and the novel Re(IV) complex (HNEt3)(NBu4)[ReCl4(H2L)] was prepared and characterized. The structure and spectroscopy of the compound H4L and its Re(IV) complex were studied experimentally and by means of density functional calculations. © 2009 Elsevier B.V. All rights reserved.


Arizaga L.,Catedra de Quimica Inorganica | Cerda M.F.,University of the Republic of Uruguay | Faccio R.,Laboratorio Of Cristalografia | Mombru A.W.,Laboratorio Of Cristalografia | And 4 more authors.
Inorganica Chimica Acta | Year: 2011

Reaction of sodium picolinate with FeIII oxo-centered carboxylate triangles in MeCN in the presence of PPh4Cl yields (PPh4)[Fe4O2(O2CR) 7(pic)2] (R = Ph (1), But (2)). Omitting the phosphonium cation produces [Fe8Na4O4(O 2CPh)16(pic)4(H2O)4] (3), which contains two Fe4Na2 units bridged by two picolinate ligands. X-ray crystal structures of 1 and 3 are reported. Voltammetric profiles in MeCN show four one-electron reduction steps for complexes 1 and 2. Variable-temperature magnetic susceptibility measurements in polycrystalline samples of 1 and 3 reveal strong antiferromagnetic couplings leading to S = 0 ground states. © 2011 Elsevier Ltd. All rights reserved.


Vazquez S.,Laboratorio Of Cristalografia | Davyt S.,Laboratorio Of Cristalografia | Basbus J.F.,Grupo Caracterizacion de Materiales | Soldati A.L.,Grupo Caracterizacion de Materiales | And 4 more authors.
Journal of Solid State Chemistry | Year: 2015

Nanocrystalline La0.6Sr0.4Fe0.8Cu0.2O3-δ (LSFCu) material was synthetized by combustion method using EDTA as fuel/chelating agent and NH4NO3 as combustion promoter. Structural characterization using thermodiffraction data allowed to determine a reversible phase transition at 425 °C from a low temperature R-3c phase to a high temperature Pm-3m phase and to calculate the thermal expansion coefficient (TEC) of both phases. Important characteristics for cathode application as electronic conductivity and chemical compatibility with Ce0.9Gd0.1O2-δ (CGO) electrolyte were evaluated. LSFCu presented a p-type conductor behavior with maximum conductivity of 135 S cm-1 at 275 °C and showed a good stability with CGO electrolyte at high temperatures. This work confirmed that as prepared LSFCu has excellent microstructural characteristics and an electrical conductivity between 100 and 60 S cm-1 in the 500-700 °C range which is sufficiently high to work as intermediate temperature Solid Oxide Fuel Cells (IT-SOFCs) cathode. However a change in the thermal expansion coefficient consistent with a small oxygen loss process may affect the electrode-electrolyte interface during fabrication and operation of a SOFC. © 2015 Elsevier Inc. All rights reserved.


Bello L.,Venezuelan Institute for Scientific Research | Quintero M.,Venezuelan Institute for Scientific Research | Quintero M.,Laboratorio Of Cristalografia | Mora A.J.,Laboratorio Of Cristalografia | And 5 more authors.
CrystEngComm | Year: 2015

Three new coordination polymers based on the combination of rctt-1,2,3,4-cyclobutanetretracarboxylic acid (rctt-H4Cbtc) and trans-1,2-bis(4-pyridyl)ethane (4,4′-bpe) and Zn and Ni metal centers were synthesized under hydrothermal conditions and structurally characterized either by X-ray single crystal or powder diffraction: [Zn2(4,4′-bpe)(rctt-Cbtc)(OH2)]n·4H2O (1), [Zn(4,4′-bpe)0.5(rctt-Cbtc)0.5(OH2)]n (2) and [Ni2(4,4′-bpe)2(rctt-Cbtc)(OH2)6] (3). The crystal structure of 1 formed a 3-D coordination polymer. A similar building unit is found in 2 but it forms as a part of a polymeric 2-D array, where the bipyridine displays a gauche conformation in contrast to the anti conformation found for 1. In 3, the replacement of Zn with Ni as a node produces a novel supramolecular array based on a 1-D coordination polymer, which is constructed from chains bearing 4,4′-bpe in an anti configuration. A sequential hydrothermal transformation was observed between 1 and 2 in the range between 80 and 120 °C, respectively. An increase in time or temperature of reaction favored the formation of 2 below 140 °C. The solid phases of 1 and 2 are metastable above 140 °C. A novel unidentified phase is observed at 180 °C, starting from the same chemical precursors in a similar molar ratio. DFT calculations corroborate the experimental observations; compound 2 is a little more stable than 1. The energy lost when water leaves the Zn atom is partially compensated by the O atom of the rctt-Cbtc ligand and could induce the formation of compound 2. © The Royal Society of Chemistry 2015.


Delgado G.E.,Laboratorio Of Cristalografia | Guillen M.,Laboratorio Of Cristalografia | Ramirez J.W.,Laboratorio Of Cristalografia | Mora A.J.,Laboratorio Of Cristalografia | And 2 more authors.
Powder Diffraction | Year: 2016

N-Acylamino acid isomers: ortho, meta, and para-methylhippuric acids, are specific xylene metabolites. Here, we report X-ray powder diffraction data, unit-cell parameters, and space groups for the three isomer (C10H11NO3), [ortho-methylhippuric acid 2 mHA, monoclinic P21/n cell, a = 8.522(1), b = 10.443(1), c = 10.734(1) Å, β = 92.43(1)°, V = 954.5(1) Å3; meta-methylhippuric acid 3 mHA, monoclinic C2/c cell a = 20.0951(2), b = 10.485(1), c = 10.074(2) Å, β = 119.08(1)°, V = 1933.9(1) Å3; para-methylhippuric acid 4 mHA, orthorhombic P212121 cell, a = 5.1794(7), b = 8.279(1), c = 22.276(2) Å, V = 955.2(2) Å3], space group. In each case, all measured diffraction peaks were indexed and are consistent with the corresponding space group. Copyright © International Centre for Diffraction Data 2016.


Santi E.,Quimica Inorganica DEC | Viera I.,Quimica Inorganica DEC | Mombru A.,Laboratorio Of Cristalografia | Castiglioni J.,Fisicoquimica DETEMA | And 2 more authors.
Biological Trace Element Research | Year: 2011

Five new copper and zinc heteroleptic complexes with saccharin and aminoacids with general stoichiometry Na 2[M(sac) 2(aa) 2]·nH 2O (M denotes Cu or Zn, sac the saccharinate ion, and aa the aminoacids) were synthesized and characterized by elemental and thermogravimetric analysis, conductimetric measurements and IR, Raman and UV-vis spectroscopies. In all the complexes, copper and zinc ions coordinated with the aminoacids through the terminal amine and carboxylate residues and with saccharin through the heterocyclic nitrogen atom. Besides, the superoxide dismutase-like activity of the heteroleptic copper complexes was evaluated and compared with the homoleptic copper amino acid complexes with the aim to observe the influence of the saccharin coordination. © 2011 Springer Science+Business Media, LLC.


Delgado G.E.,Laboratorio Of Cristalografia | Mora A.J.,Laboratorio Of Cristalografia | Contreras J.E.,Laboratorio Of Cristalografia | Betancourt L.,University of Los Andes, Venezuela
Bulletin of Materials Science | Year: 2010

Mn2SnTe4 was synthesized by direct fusion using the anneal method. X-ray powder diffraction analysis indicated that this material crystallizes in the olivine-type structure, space group Pnma, Z = 4, with unit cell parameters: a = 14.020(2) Å, b = 8.147(1) Å, c = 6.607(1) Å, V = 754.7(2) Å3. The Rietveld refinement converged to the figures of merit, Rp = 6.9%, Rwp = 8.5%, R exp = 6.0%, χ2 = 2.0 and S = 1.4. © Indian Academy of Sciences.

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