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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. Fil: Piro, Oscar Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; Argentina

Durante 2012 se celebraron dos acontecimientos científicos relacionados. Uno de ellos es el Centenario de un descubrimiento cardinal de la Física, esto es el fenómeno de difracción de rayos-X por cristales, realizado por Walter Friedrich, Paul Knipping y Max von Laue. La instrumentación e interpretación de este fenómeno por el trabajo pionero de William Henry Bragg y su hijo William Lawrence Bragg inició el desarrollo de los hoy poderosos métodos de análisis estructural. Dichos métodos estructurales por difracción de rayos-X resultarían clave en el otro acontecimiento que se conmemoró en 2012: el Cincuentenario del Premio Nobel en Fisiología o Medicina otorgado a Francis Crick, James Watson y Maurice Wilkins por sus trabajos de 1953 sobre la estructura molecular del ácido desoxirribonucleico (ADN), la sustancia de la herencia, un hallazgo fundamental para el entendimiento del fenómeno natural más extraordinario: la Vida. A sesenta años de la culminación de aquellos trabajos, hacemos aquí una descripción sucinta de los eventos que desembocaron en uno de los descubrimientos científicos más importantes del siglo XX., During 2012 two related scientific breakthroughs were celebrated. One of them was the Centennial of a cardinal discovery in Physics, namely the X-ray diffraction by crystals, by Walter Friedrich, Paul Knipping and Max von Laue. The instrumentation and interpretation of this phenomenon by the pioneer work of William Henry Bragg and his son William Lawrence Bragg paved the way for the development of the today powerful methods of structural analysis. These X-ray diffraction methods would play a key role in the other discovery celebrated in 2012: the fifty years of the Nobel Prize in Physiology or Medicine awarded to Francis Crick, James Watson and Maurice Wilkins for their work of 1953 on the molecular structure of deoxyribonucleic acid (DNA), the substance of the heredity, a fundamental finding for the understanding of the most extraordinary natural phenomena: Life. In the sixtieth anniversary of the culmination of those works, we succinctly describe here the events that lead to one of the major scientific discoveries of the twentieth century., Instituto de Física La Plata

Se sintetizaron dos nuevos derivados 5-nitro y 7-nitrofenantro[9,10-c][1,2,5]tiadiazol 2,2-dióxido, por nitración convencional del compuesto padre, con un redimiendo global ca. 55%. Las estructuras de los dos isómeros se dilucidaron por medio de estudios de difracción de rayos-X. Por reducción química de ambos compuestos con cianuro de litio se obtuvieron aniones-radicales estables derivados de los mismos, los cuales se caracterizaron espectroscópicamente (UV-Vis, EPR). Los derivados nitrados se ensayaron como inhibidores de la corrosión de Cu en H2SO4 0,25 M, lográndose una eficiencia de inhibición máxima del 84 %. Se efectuaron ensayos de citoxicidad de los derivados nitrados, encontrándose que para concentraciones inferiores a 10,8 M no presentan efectos desfavorables en la línea celular CHO-K1 Two new 5-nitro and 7-nitro derivatives were synthesized by conventional nitration procedure of phenanthro [9,10-c] [1,2,5] thiadiazole 2,2-dioxide with ca. 55% of global yield. Their structures were elucidated by of X-ray diffraction studies. Stable radical-anions were obtained by chemical reduction of the nitrated derivatives with lithium cyanide, which were characterized by spectroscopic measurements (UV-Vis, EPR). Nitro derivatives were tested as corrosion inhibitors for Cu in 0.25 M H2SO4 with a maximum of inhibition efficiency of 84%. Cytotoxicity assays of the nitro compounds were performed and it was found that for concentrations lower than 10.8 M they have not adverse effects on the cell line CHO-K1. Fil: Banera, Mauro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicaciones; Argentina Fil: Caram, Jorge Pablo. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - Santa Fe. Instituto de Fisica del Litoral; Argentina Fil: Gennaro, Ana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); Argentina Fil: Grillo, Claudia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicaciones; Argentina Fil: Piro, Oscar Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - La Plata. Instituto de Fisica La Plata; Argentina Fil: Mirifico, Maria Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicaciones; Argentina

The formation and characterisation of a polymeric copper complex produced by chemical reaction between copper (II) ions and 3-mercapto1-propanesulphonate sodium salt (MPSA) were studied. The formation of this complex, followed by sequential UVevisible spectroscopic measurements, involves the reduction of Cu(II) ions to Cu(I) by MPSA, the latter being oxidised to bis-(3-sulphopropyl)-disulphide (SPS), a dimer of MPSA. In the presence of oxygen, the re-oxidation of Cu(I) to Cu(II) results in the formation of polymeric complex species consisting of [Cu(SO3(CH2)3S-S(CH2)3SO3)(H2O)4] units. Single crystal X-ray diffraction shows that this polymeric copper complex crystallizes in the monoclinic C2/c space group. The Cu(II) ion in the complex structure lies on an inversion centre in an elongated octahedral environment, equatorially coordinated to four water molecules and axially to two MPSA ligands through one of their sulphonic oxygen atoms. The complex units are arranged in the lattice as polymeric [Cu(SPS)(H2O)4]n molecules extending along the crystal [101] direction. The IR and Raman spectra as well as TGA and DTA data are reported. The stepwise thermal decomposition from room temperature up to 1000 C begins with the loss of water molecules and ends with the formation of copper sulphide species., Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas

The synthesis and characterization of the first two Re complexes with semicarbazone ligands is presented. Selected ligands are 5-Nitro-2-furaldehyde semicarbazone (Nitrofurazone) (L1) and its derivative 3-(5-Nitrofuryl)acroleine semicarbazone (L2). Complexes of general formula [RevOCl2(PPh3)L], where L = L1 and L2, were prepared in good yields and high purity by reaction of [RevOCl3(PPh3)2] with L in ethanol or methanol solutions. The complexes formula and molecular structures were supported by elemental analyses and electronic, FTIR, 1H, 13C and 31P NMR spectroscopies. In addition, the crystal and molecular structure of [RevOCl2(PPh3)L2] was determined by X-ray diffraction methods. [ReOCl2(PPh3)(3-(5-Nitrofuryl)acroleine semicarbazone)] crystallizes in the space group P-1 with a = 11.2334(2), b = 11.3040(2), c = 12.5040(2) Å, α = 81.861(1), β = 63.555(1), γ = 83.626(1)°, and Z = 2. The Re(V) ion is in a distorted octahedral environment, equatorially coordinated to a deprotonated semicarbazone molecule acting as a bidentate ligand through its carbonylic oxygen and azomethynic nitrogen atoms, to an oxo ligand and a chlorine atom. The six-fold coordination is completed by another chlorine atom and a triphenylphosphine ligand at the axial positions. Fil: Otero, L.. Universidad de la República Facultad de Química; Uruguay Fil: Noblia, P.. Universidad de la República Facultad de Química; Uruguay Fil: Gambino, D.. Universidad de la República Facultad de Química; Uruguay Fil: Cerecetto, H.. Universidad de la República Facultad de Química; Uruguay Fil: González, M.. Universidad de la República Facultad de Química; Uruguay Fil: Sánchez-Delgado, R.. Instituto Venezolano de Investigaciones Científicas; Venezuela Fil: Castellano, E.E.. Universidade de Sao Paulo; Brasil Fil: Piro, Oscar Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina

The title compound crystallizes in the triclinic space group P͞1, with a = 8.6161(4) Å, b = 10.591(1) Å, c = 11.406(1) Å, α = 67.976(7)°, β = 86.868(6)°, γ = 67.798(6)°, and Z = 1. The structure was refined to R1 = 0.0413. The decavanadate anion V₁₀O₂₈⁶⁻ and the [Na₂(H₂O)₁₀]²⁺ bridged cation are located at inversion centers. Partial deuteration of the substance indicates that the coordinated water molecules are strongly asymmetric, forming weak hydrogen bonds with acceptor oxygen atoms from the decavanadate anion. The infrared and Raman spectra are dominated by the water and decavanadate anion bands., Instituto de Física La Plata, Centro de Química Inorgánica

We report the molecular structure and a single crystal EPR study at 9.8 and 33.9 GHz of a new copper(II) compound with the amino acid L-Glutamine, Cu[NH2CO2CH(CH2)2CONH2]2. The CuII ion is in an elongated octahedral environment equatorially trans-coordinated by two glutamine molecules acting as bidentate ligands through the nitrogen atom and one oxygen atom of each amino acid group, and axially by two carboxylate oxygen atoms of two neighboring glutamine molecules. Copper ions are arranged in layers connected by syn-anti carboxylate bridges that provide equatorial and apical ligands to the copper ions. Neighboring layers are connected by long chemical paths, which include two amino acid side chains connected by H bonds. Single crystal EPR spectra show a single exchange-collapsed resonance at both microwave frequencies for any magnetic field orientation. The evaluation of the molecular g-tensor from the angular variation of the EPR line position yielded g⊥ = 2.051 and g|| = 2.248, which indicates a dmath image ground orbital for the Cu ions. The angular variation of the EPR line width displays a contribution that is typical of a 2-D magnetic system, and another contribution depending on the microwave frequency, which is attributed to the incomplete collapse of the resonances corresponding to magnetically nonequivalent copper ions. A quantitative analysis of the line width data allowed us to estimate a mean exchange coupling constant |J/k| = 0.42(2) K, which is assigned to the syn-anti carboxylate chemical path that connects neighboring copper ions within a layer. The results are discussed and compared with those observed in similar systems. Fil: Schveigkardt, J.. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; Argentina Fil: Rizzi, Alberto Claudio. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; Argentina Fil: Piro, Oscar Enrique. Universidad Nacional de La Plata; Argentina Fil: Castellano, E.E.. Universidade de Sao Paulo; Brasil Fil: Costa de Santana, R.. Universidade Federal de Goiás; Brasil Fil: Calvo, Rafael. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Brondino, Carlos Dante. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina

An isolated reaction intermediate in the desulfurization of thiones promoted by phosphanes is provided by the ylide derivative 3, which is obtained by thiophilic addition of PCy3 to 2. Complex 2 is formed from the disulfide‐containing dimetallic complex 1 by scission of the S−S bond. [Mn]=Mn(CO)4+, R=Ph. Fil: Ruiz, Javier. Universidad de Oviedo; España Fil: Ceroni, Mario. Universidad de Oviedo; España Fil: Quinzani, Oscar Valentín. Universidad de Oviedo; España Fil: Riera, Víctor. Universidad de Oviedo; España Fil: Piro, Oscar Enrique. Universidad de Oviedo; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina