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201. N-nitrosomelatonin

Author

Turjanski, Adrián, Chaia, Zulema Débora, Doctorovich, Fabio, Estrin, Dario, Rosenstein, Ruth, and Piro, Oscar Enrique

Subjects
Física, Cristalografía
Abstract

The title compound, N-[2-(5-methoxy-1-nitroso-1H-indol-3-yl)ethyl]acetamide, C13H15N3O3, an N-nitroso derivative of melatonin, crystallizes in the monoclinic C2/c space group. The molecules are arranged in such a way that the aromatic rings are in a planar conformation, with the alkylamide side chains in a different plane, at a dihedral angle of 108.60 (6)°. The alkylamide chains are interconnected by hydrogen bonds, constituting an infinite array., Facultad de Ciencias Exactas

Published
2000

202. Structural and spectroscopic characterization of tris (o-phenanthroline)iron(II) disaccharinate monosaccharin hexahydrate

Author

Williams, Patricia Ana María, Ferrer, Evelina Gloria, Pasquevich, Karina Alejandra, Baran, Enrique José, Castellano, Eduardo Ernesto, and Piro, Oscar Enrique

Subjects
crystal structure, o-phenanthroline, saccharinate, Química, Iron(II), spectroscopic properties, thermal behavior, Ciencias Exactas
Abstract

The crystal and molecular structure of the title compound, for short [Fe(o-phen)3](sac)2·(Hsac)·6H2O, has been determined by X-ray diffraction methods. It crystallizes in the monoclinic space group P21/n with a = 16.3190(1), b = 19.2890(1), c = 17.4490(2) A, β = 92.586(1)°, V = 5486.95(8) A3 and, Z = 4. The investigated compound constitutes the first example of a species in which uncoordinated saccharin and saccharinate anions are present in the structure. The crystallographic results reveal the subtle differences between the structure of the neutral molecule and its anion. The complex was also characterized by means of infrared, electronic, and 57Fe-Mossbauer spectroscopy. Its magnetic susceptibility was determined at room temperature and its thermal behavior investigated by means of thermogravimetric and differential thermal analytical techniques., Centro de Química Inorgánica

Published
2000

203. N-nitrosomelatonin

Author

Turjanski, Adrián, Chaia, Zulema Débora, Doctorovich, Fabio, Estrin, Dario, Rosenstein, Ruth, and Piro, Oscar Enrique

Subjects
Física, Cristalografía, General Medicine, General Biochemistry, Genetics and Molecular Biology
Abstract

The title compound, N-[2-(5-methoxy-1-nitroso-1H-indol-3-yl)ethyl]acetamide, C13H15N3O3, an N-nitroso derivative of melatonin, crystallizes in the monoclinic C2/c space group. The molecules are arranged in such a way that the aromatic rings are in a planar conformation, with the alkylamide side chains in a different plane, at a dihedral angle of 108.60 (6)°. The alkylamide chains are interconnected by hydrogen bonds, constituting an infinite array. Facultad de Ciencias Exactas

Published
1999

204. Crystal and molecular structure determination, TGA, DTA, and infrared and Raman spectra of rubidium nitroprusside monohydrate, Rb₂[Fe(CN)₅NO] . H₂O

Author

Soria, Delia Beatriz, Piro, Oscar Enrique, Castellano, Eduardo Ernesto, and Aymonino, Pedro José

Subjects
Crystal structure, Properties, Rubidium nitroprusside monohydrate, Química
Abstract

The crystal structure of rubidium nitroprusside monohydrate, Rb₂[Fe(CN)₅NO] . H₂O, has been determined from X-ray diffraction data and refined using direct and Fourier methods to R = 0.066 and Rw = 0.075, employing 1894 independent reflections with I > 3 (I). The substance crystallizes in the monoclinic space group C2/c (C62h), with a = 13.987(2), b = 10.241(1), c = 18.151(1) Å, β = 110.94°, and Z = 8. Anions are located at C1 sites, one per asymmetric unit, and are slightly distorted octahedra. TGA, DTA, FTIR, and FTIR Raman results were interpreted on the basis of the formula of the compound, its crystal structure, and the behavior of other nitroprussides., Centro de Química Inorgánica

Published
1999

205. Crystal structure and EPR spectra of glycilglycilglycinocopper(II)bromide sesquihydrate

Author

Castellano, Eduardo Ernesto, Piro, Oscar Enrique, Casado, Nieves M. C., Brondino, Carlos D., and Calvo, Rafael

Subjects
Cu(II) complex, crystal structure, Química, Ciencias Exactas, EPR spectra
Abstract

The title compound, Cu(glyglygly)Br·1·5H2O, crystallizes in the space group C2/c, with a = 21.468(7), b = 6.716(5), c = 16.166(6) A, β = 98.39°, and Z = 8. The tripeptide is bonded to one Cu(II) ion through the nitrogen [Cu–N=1.97(1)A] and oxygen [Cu–O=2.019(8)A] atoms of the amino end glycine residue and to another Cu(II) through one oxygen atom [Cu–O=1.931(9)A] of the terminal carboxyl group. This give rise to covalently bonded and infinite ···–Cu–tripeptide–Cu–··· chains. These chains are linked to one another by a network of H-bonds involving the water molecules and bromide ions. The Cu(II) ion is in a distorted tetragonal pyramidal coordination polyhedron. At the corner of the base of the pyramid are the terminal glycine nitrogen and oxygen atoms of one tripeptide, a carboxylic oxygen of another tripeptide and a bromide ion. The fivefold coordination is completed with a water molecule at the top of the pyramid [Cu–Ow=2.286(9)A]. For all orientations of the applied magnetic field the single crystal EPR spectra display a single anisotropic exchange collapsed resonance without hyperfine structure. Its position was measured in three perpendicular planes and the crystal g-tensor evaluated from the data. This tensor is interpreted in terms of the contributing Cu(II) complexes in the unit cell to deduce the principal values g1 = 2.273, g2 = 2.050 and g3 = 2.131 for the molecular gyromagnetic tensor. We also discuss the magnitude of the exchange interaction between neighboring copper ions in the lattice on the basis of the features in the EPR spectra and the structural information., Facultad de Ciencias Exactas

Published
1998

208. Centennial of X-ray diffraction: development of an unpromising experiment with a wrong explanation.

Author

Piro, Oscar E.

Subjects
*X-ray diffraction, *CRYSTALLOGRAPHY, *CRYSTAL optics, *ELECTROMAGNETIC radiation
Abstract

In February 1912 in Munich, P. P Ewald, one of A. Sommerfeld's Ph.D. students, consulted M. Laue on matters related to crystal optics, his thesis subject. During the conversation, Laue conceived the idea that a crystal might act as a three-dimensional diffraction grating to the X-rays. Despite the idea having met with scepticism among his colleagues, Laue succeeded in getting the help of two of W. C. Roentgen's doctorands: F. Friedrich, Sommerfeld's laboratory assistant, and P. Knipping: to undertake the, by now, legendary experiments that originated a new branch of Physics. The results solved two fundamental questions of the time: namely are the X-rays electromagnetic radiation (light) of very short wavelength? And also, do the crystals have spatial periodic arrangements? The affirmative answer to both questions was immediately followed in 1913 by the instrumentation and re-interpretation of the phenomenon through the pioneering work by W. H. Bragg and his son W. L. Bragg, who paved the way to the portentous development of structural crystallography by X-ray diffraction that took place during the last hundred years. [ABSTRACT FROM PUBLISHER]

Published
2016
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209. Structural and IR-spectroscopic characterization of magnesium acesulfamate.

Author

Piro, Oscar E., Echeverría, Gustavo A., Parajón-Costa, Beatriz S., and Baran, Enrique J.

Subjects
*MAGNESIUM, *MAGNESIUM carbonate, *X-ray diffraction, *TRICLINIC crystal system, *MAGNESIUM group
Abstract

Magnesium acesulfamate, Mg(C4H4NO4S)2·6H2O, was prepared by the reaction of acesulfamic acid and magnesium carbonate in aqueous solution, and characterized by elemental analysis. Its crystal structure was determined by single crystal X-ray diffraction methods. The substance crystallizes in the triclinic space group P1̅ with one molecule per unit cell. The FTIR spectrum of the compound was also recorded and is briefly discussed. Some comparisons with other simple acesulfamate and saccharinate salts are also made. [ABSTRACT FROM AUTHOR]

Published
2016
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210. Crystal structure and EPR spectrum of dimeric di-μ-azide-bis[cyanide(N,N-diethylethylenediamine)]-copper(II), [Cu(N₃)(NCO)(diEten)]₂

Author

Piro, Oscar Enrique, Castellano, Eduardo Ernesto, Zukerman Schpector, Julio, De Simone, C. A., Martino, D. M., and Steren, C. A.

Subjects
copper(II) dimer, Crystal structure, EPR spectrum, Física, Química
Abstract

The title compound, [Cu(N₃)(NCO)(C₆H₁₆N₂)]₂, crystallizes in the space groupP2₁/n, witha=8.336(1),b=17.405(3),c=8.376(1) Å, β=109.73(2)o andZ=4. The molecules are arranged as centrosymmetric dimers in which two azide ligands bridge neighboring copper ions in an asymmetric head-on fashion. The Cu(II) ion is coordinated to five nitrogen atoms which form a distorted tetragonal pyramid. At the pyramid base are the two N atoms of a diEten molecule [Cu−N=2.00(1), 2.130(9) Å], an azide end atom [Cu−N=1.99(1) Å] and a NCO group [Cu−N=1.93(1) Å]. At the pyramid apex is the other, inversion related, azide N atom in the dimer [Cu−N=2.38(1) Å]. This Cu−N contact links the monomers within a dimer. Neighboring dimers are coupled by weak N−H…O contacts. Single crystal EPR data at X-band show that the pair of resonances expected for neighboring, magnetically nonequivalents dimers, collapse into a single line, a signature of inter-dimers superexchange coupling. The observed crystal gyromagnetic tensor is used to disclose the electronic and magnetic structure around Cu(II) ions., Facultad de Ciencias Exactas

Published
1997

211. The crystal and molecular structure of ammonium-bis(malonato) oxovanadium(IV) dihydrate

Author

Piro, Oscar Enrique and Baran, Enrique José

Subjects
crystal structure, IR and Raman spectra, Física, Ciencias Exactas, Bis(malonato)oxovanadiumt(lV)
Abstract

The title compound, (NH4)2[VO(C3H2O4)2]·2H2O, crystallizes in the monoclinic space group P21/n, with a=7.1889(7), b=19.254(2), c=9.879(2) A, β=108.19(1)o, and Z=4. The VO2+ cation is five-fold coordinated with two malonate anions acting as bidentate ligands and a water molecule. Infrared and Raman spectra are also reported to attain a wider insight into the compound characteristics., Departamento de Física

Published
1997

212. Crystallographic new light on an old complex: NaMg[Cr(oxalato) 3 ]·9H 2 O and structure redetermination of the isomorphous aluminum(III) compound.

Author

Piro, Oscar E., Echeverría, Gustavo A., González-Baró, Ana C., and Baran, Enrique J.

Subjects
*CRYSTALLOGRAPHY, *SODIUM compounds, *COMPLEX compounds, *ALUMINUM compounds, *CRYSTAL structure, *X-ray diffraction, *METAL complexes
Abstract

The crystal structure of sodium and magnesiumtris(oxalato)chromato(III) nona hydrate, NaMg[Cr(C2O4)3]·9H2O, has been determined by X-ray diffraction methods. It crystallizes in the trigonalP3c1 space group with (in the hexagonal setting)a = b = 16.9635(4),c = 12.5247(3) Å, andZ = 6 molecules per unit cell. The Cr(III) and sodium ions are in octahedral environments coordinated to three oxalate molecules and arranged in a honeycomb-like layered structure perpendicular to the crystalc-axis. There are three different octahedral [Mg(H2O)6]2+hydrated ions that fill the honeycomb holes giving rise to electrically neutral Na[Mg(H2O)6][Cr(oxalato)3] crystal slabs. Neighboring slabs are bridged by the remaining three water molecules through H-bonds and therefore the whole crystal can be more properly described as Na[Mg(H2O)6][Cr(oxalato)3]·3H2O. Also, the structure of isomorphous NaMg[Al(C2O4)3]·9H2O compound has been re-examined and compared with the chromium(III) complex. Infrared and Raman spectra of both complexes were also recorded and briefly discussed. [ABSTRACT FROM PUBLISHER]

Published
2015
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213. Estructura molecular y espectro de RPE de [Cu(L-proIina)₂]₂.5H₂0

Author

Castellano, Eduardo Ernest, Piro, Oscar Enrique, Sartoris, R., Ortigoza, L., Casado, N., and Calvo, R.

Subjects
Física, Caracterización estructural y magnética, Nuevo compuesto
Abstract

Reportamos una caracterización estructural y magnética del nuevo compuesto de [Cu(L-prolina)₂]₂.5H₂0 (C₂₀CU₂H₄₂N₄O₁₃). Cristaliza en el grupo espacial P2₁, con a=11.187(1)A, b=12.172(3)A, c=11.661(1)Á, β=114.96(1)A y Z=2. Los átomos no-H fueron localizados empleando 1834 difracciones de rayos-X con intensidades I>3σ(I). Un mapa de diferencias de Fourier mostró ocho de los diez hidrógenos de las cinco moléculas de agua. Esos hidrógenos, junto con los de las prolinas ubicados estereoquímicamente, fueron incorporados al modelo molecular para el refinamiento final (R=3.8%). En los dos grupos Cu(L- prolina)₂ independientes, el Cu(II) exhibe una coordinación equatorial cuadrada trans con un par de oxígenos y de nitrógenos pertenecientes a sendas prolinas. En un grupo, la coordinación piramidal se completa con un agua apical. En el otro, la coordinación es octahédrica elongada y se completa con dos aguas axiales. Los espectros de resonancia paramagnética electrónica (RPE) a 9.7 GHz de muestras monocristalinas mostraron una única resonancia para toda orientación del campo magnético y se midió su posición y ancho en tres planos cristalinos. Se discuten los autovalores obtenidos para el tensor g molecular en términos de la geometría y estructura electrónica moleculares de [Cu(L-prolina)₂]₂.5H₂0 y de las interacciones de intercambio entre iones cobre., Facultad de Ciencias Exactas

Published
1996

214. Water‐Soluble (Pterin)rhenium(I) Complex: Synthesis, Structural Characterization, and Two Reversible Protonation–Deprotonation Behavior in Aqueous Solutions

Author

Ragone, Fabricio, primary, Ruiz, Gustavo T., additional, Piro, Oscar E., additional, Echeverría, Gustavo A., additional, Cabrerizo, Franco M., additional, Petroselli, Gabriela, additional, Erra‐Balsells, Rosa, additional, Hiraoka, Kenzo, additional, García Einschlag, Fernando S., additional, and Wolcan, Ezequiel, additional

Published
2012
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219. Analgesic and Anti-Inflammatory Activities of Salicylaldehyde 2-Chlorobenzoyl Hydrazone (H2LASSBio-466), Salicylaldehyde 4-Chlorobenzoyl Hydrazone (H2LASSBio-1064) and Their Zinc(II) Complexes

Author

Júnior, Walfrido Bispo, primary, Alexandre-Moreira, Magna S., additional, Alves, Marina A., additional, Perez-Rebolledo, Anayive, additional, Parrilha, Gabrieli L., additional, Castellano, Eduardo E., additional, Piro, Oscar E., additional, Barreiro, Eliezer J., additional, Lima, Lídia Moreira, additional, and Beraldo, Heloisa, additional

Published
2011
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221. Binuclear zinc(II) complexes with the anti-inflammatory compounds salicylaldehyde semicarbazone and salicylaldehyde-4-chlorobenzoyl hydrazone (H2LASSBio-1064)

Author

Parrilha, Gabrieli L., primary, Vieira, Rafael P., additional, Rebolledo, Anayive P., additional, Mendes, Isolda C., additional, Lima, Lidia M., additional, Barreiro, Eliezer J., additional, Piro, Oscar E., additional, Castellano, Eduardo E., additional, and Beraldo, Heloisa, additional

Published
2011
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223. On the synthesis and structures of the complexes [RuCl(L)(dppb)(N–N)]PF6 (L = CO, py or 4-NH2py; dppb = 1,4-bis(diphenylphosphino)butane; N–N = 2,2′-bipyridine or 1,10-phenanthroline) and [(dppb)(CO)Cl2-Ru-pz-RuCl2(CO)(dppb)] (pz = pyrazine)

Author

Frazão Barbosa, Marilia I., primary, Valle, Eliana M.A., additional, Queiroz, Salete L., additional, Ellena, Javier, additional, Castellano, Eduardo E., additional, Malta, Valéria R.S., additional, de Sousa, Jackson R., additional, Piro, Oscar, additional, de Araujo, Márcio P., additional, and Batista, Alzir A., additional

Published
2010
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248. Synthesis and structural characterization of two new polynuclear metal thiosaccharinates: Hexakis(thiosaccharinato)hexasilver(I) and tetrakis(thiosaccharinato)tetracopper(I)

Author

Dennehy, Mariana, primary, Tellería, Gabriela P., additional, Tarulli, Susana H., additional, Quinzani, Oscar V., additional, Mandolesi, Sandra D., additional, Guida, Jorge A., additional, Echeverría, Gustavo A., additional, Piro, Oscar E., additional, and Castellano, Eduardo E., additional

Published
2007
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