Suchergebnisse

Cyclometallated compounds have been extensively studied, in particular those with palladium and platinum. This is because of their possible applications in medicinal chemistry, as anticancer or antimicrobial agents; in some cases, with similar results as cisplatin, carboplatin or oxaliplatin. What is also remarkable is their use as homogeneous catalysts, for example, in cross coupling reactions such as Suzuki–Miyaura or Mizoroki–Heck. Herein, we report the synthesis of different thiosemicarbazone ligands, which will be reacted with a palladium or platinum salt, to give the corresponding cyclometallated compounds; in addition, their reactivity with bis(diphenylphosphino)methane (dppm) will be studied. Characterization has been carried out by elemental analysis, IR spectroscopy, 1H and 31P NMR spectroscopy. Additionally, 1c has been studied by X-ray diffraction ; Francisco Reigosa wants to thank the Spanish Government (AEI) for their financial support through an FPU grant (number 13/05014). The authors thank funding from Xunta de Galicia (Galicia, Spain) under the Grupos de Referencia program (GRC 2019/014) ; SI

Mixed crystals Cs1−x(NH4)xH2PO4 of the ferroelectric CsH2PO4 (CDP) and the antiferroelectric (NH4)H2PO4 were grown with x=0.2 (CADP0.2) in solution. The structural properties of the crystal were analyzed by means of x-ray diffraction. Dielectric measurements at several temperatures and frequencies have been performed along the three crystallographic axes in this sample and also in the fully deuterated CADP0.2 sample (DCADP0.2). NMR experiments were also performed. ; NSFgrantDMR-9520215; Basque Government under grant BFI96.041

<p>Hypereutectoid steel wire rod of diameter 6.40 mm is lead patented in lead bath of an electric powered furnace and then it is cold drawn through converging conical dies in a die sequence up to 2.50 mm diameter. The drawn wires subjected to different true strain are analysed using line profile X-ray diffraction methods. The classical Williamson-Hall plot as well as modified Williamson-Hall plot of drawn wire specimens of different true strain is plotted. The theoretical as well as experimental value of q is evaluated. The q is a parameter which depends up on elastic constant of the crystal and type of dislocations. The changes in nature of dislocations from edge dislocations to screw dislocations are calculated against true strain and are verified by scanned electron microscopy's micrograph of drawn wire.</p>

Boron nitride (BN) layers with sp(2) bonding have been grown by metal organic chemical vapor deposition on AlN underlayers, which are deposited on c-plane sapphire substrates. Two different boron precursors were employed-trimethylboron and triethylboron-while ammonia was used as the nitrogen precursor. The BN obtained epitaxial BN films contain ordered rhombohedral (rBN) and partially ordered turbostratic (tBN) stackings as evidenced by x-ray diffraction analysis. We discriminatively identify the PL signatures of the rBN and tBN from those typical of the hexagonal (hBN) and Bernal stackings (bBN). The optical signature of tBN appears at 5.45eV, and it intercalates between the two recombination bands typical of rBN at 5.35eV (strong intensity) and 5.55eV(weaker intensity). The analogs of the high intensity band at 5.35eV in rBN sit at 5.47eV for hBN and at 5.54eV for bBN. ; Funding Agencies|network GaNeX [ANR-11-LABX-424 0014]; BONASPES project [ANR-19-CE30 0007]; ZEOLIGHT project [ANR-19-CE08-0016]; Universite de Montpellier; Swedish Research CouncilSwedish Research CouncilEuropean Commission [2017-04164]; Swedish Foundation for Strategic Research (SSF)Swedish Foundation for Strategic Research [IS14-0027]; Carl Tryggers Foundation for Scientific Research [CTS 14:189]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University [2009-00971]; Office of Naval ResearchOffice of Naval Research [N00014-20-1-2474, 428]; National Science FoundationNational Science Foundation (NSF) [CMMI 429, 1538127]

Abstract
The temperature dependence of unit cell parameters was studied using high-temperature X-ray diffraction and the coefficient of thermal expansion of SnSe single crystal was determined. Fluorescence spectra of SnSe single crystal grown by the Bridgman-Stockbarger method were examined using a Cary Eclipse spectrophotometer at room temperature in the wavelength range 200–900 nm. When the samples were irradiated by a pulse at a wavelength of 230 nm, the fluorescence spectra exhibited maxima at wavelengths 313.07, 423.03, 458.93, 495.07, and 530.00 nm.

Methods based on X-ray diffraction commonly used to decipher diagenetic/low- grade metamorphic conditions are revised and evaluated according to our current knowledge of related geological processes obtained via transmission electron microscopy. A lack of evident qualitative changes in phyllosilicates, including their mineral chemistry, from deep diagenetic to low-epizone conditions explains the scarcity of valid grade criteria. Throughout this range of diagenetic-metamorphic conditions a progressive increase in the crystalline domain size together with a decrease in the number of defects are the only significant changes to be observed. Therefore indices related to crystallinity still remain the most successful methods based on the crystal- chemical characteristics of phyllosilicates. ; Se revisan y evalúan los métodos basados en difracción de rayos X comúnmente usados para conocer las condiciones diagenéticas/metamórficas de bajo grado, de acuerdo con el conocimiento actual de los procesos geológicos relacionados obtenido por microscopía electrónica de transmisión. La falta de cambios cualitativos evidentes en los filosilicatos, incluida su química mineral, desde condiciones diagenéticas profundas hasta condiciones de epizona débil, explica la escasez de criterios de grado válidos. En toda esta gama de condiciones diagenético-metamórficas, un aumento progresivo en el tamaño del dominio cristalino junto con una disminución en el número de defectos son los únicos cambios significativos que se pueden observar. Por lo tanto, los índices relacionados con la cristalinidad siguen siendo los métodos basados en características cristaloquímicas de los filosilicatos más adecuados .