Search results for "X-Ray"

Front Cover: The Important Role of the Nuclearity, Rigidity, and Solubility of Phosphane Ligands in the Biological Activity of Gold(I) Complexes (Che…

2018

Contribution of X-Ray diffraction to the study of spin transitions in some iron (II) complexes

1991

Abstract A review of recent single crystal investigations under constraint of iron (II) spin crossover complexes is given. The systems covered are Fe L2 (NCS)2 complexes (L = Phen, Btz) and some analogous derivatives. Emphasis is laid on the correlations between structural changes associated with spin transitions and the experimentally determined characteristics of these transitions.

XAFS STUDIES OF OCTAHEDRAL AMORPHOUS OXIDES

1993

The relationships between the structures of octahedral and tetrahedral amorphous oxides, studied by XAFS spectroscopy, are considered. It was found that a-WO3, a-MoO3, a-V2O5 thin films and glasses have strongly distorted, but well defined, oxygen octahedra, which are joined by vertices (a-WO3, a-MoO3) or by vertices and edges (a-V2O5), and form a random network. At the same time, a-IrO2 and a-NiO have less distorted oxygen octahedra, which form the rutile type and rock salt type nanocrystalline structures. The variation of the structure with the change of the metal valence is considered and the possibility of small radius polaron detection by XAFS is discussed.

Structural and Magnetic Characterization of a Novel Heptanuclear Hydroxo-Bridged Copper(II) Cluster of the Corner-Sharing Dicubane Type

1994

Hexakis(dimethylformamide)iron(II) complex cation in hexahalorhenate(IV)-based salts: synthesis, X-ray structure and magnetic properties

2018

Two iron(II)-rhenium(IV) compounds of general formula [FeII(dmf)6][ReIVX6] [X = Cl (1) and Br (2); dmf = N,N-dimethylformamide] have been prepared and characterized. X-ray powder diffraction measurements on samples of 1 and 2 support the same structure for both systems. The crystal structure of 1 was determined by single-crystal X-ray diffraction. 1 crystallizes in the triclinic system with space group Pī. Each iron(II) is six-coordinate and bonded to six oxygens from six dmf molecules building a distorted octahedral environment. Rhenium(IV) is six-coordinate by six halide anions in an almost regular octahedral geometry. The magnetic properties were investigated from variable-temperature ma…

Ein makrobicyclischer Tris-bipyridin-Ligand sowie ein Cu2I- und ein Ag3I-Komplex

1991

Powder X-ray diffraction data for potassium silver thiocyanate, AgK(SCN)2 and dipotassium silver thiocyanate, AgK2(SCN)3

2002

Previously unpublished powder X-ray diffraction data for potassium silver thiocyanate, AgK(SCN)2 and dipotassium silver thiocyanate, AgK2(SCN)3 are presented. F30 values for AgK(SCN)2 and AgK2(SCN)3 are 80(0.0075, 50) and 53(0.0089, 63), respectively. The Rietveld refinement of the patterns is also performed. For AgK(SCN)2Rp=6.98, Rwp=11.84, and RBragg=2.9. For AgK2(SCN)3Rp=7.22, Rwp=10.79, and RBragg=5.0.

Structure of mammalian plasma fetuin-B and its mechanism of selective metallopeptidase inhibition

2018

The co-crystal structure of the metallopeptidase astacin with its specific protein inhibitor fetuin-B reveals a novel mechanism of inhibition.

Timing techniques applied to distributed modular high-energy astronomy: the H.E.R.M.E.S. project

2021

The HERMES-TP/SP (High Energy Rapid Modular Ensemble of Satellites -- Technologic and Scientific Pathfinder) is an in-orbit demonstration of the so-called distributed astronomy concept. Conceived as a mini-constellation of six 3U nano-satellites hosting a new miniaturized detector, HERMES-TP/SP aims at the detection and accurate localisation of bright high-energy transients such as Gamma-Ray Bursts. The large energy band, the excellent temporal resolution and the wide field of view that characterize the detectors of the constellation represent the key features for the next generation high-energy all-sky monitor with good localisation capabilities that will play a pivotal role in the future …

Quantum gravity with THESEUS

2021

AbstractIn this paper we explore the possibility to search for a dispersion law for light propagation in vacuo with a sample of Gamma-Ray Bursts detected by the THESEUS satellite. Within Quantum Gravity theories, different models for space-time quantization predict relative discrepancies of the speed of photons w.r.t. the speed of light that (in a series expansion) depend on a given power of the ratio of the photon energy to the Planck energy. This ratio is as small as 10− 23 for photons in the soft γ −ray band (100 keV). The dominant effect is determined by the first significant term of this expansion. If the first order in this expansion is relevant, these theories imply a Lorentz Invaria…