Search results for "x-ray"
showing 10 items of 4234 documents
Methyl 3',5'-dimethoxybiphenyl-4-carboxylate
2013
In the title compound, C16H16O4, the dihedral angle between the benzene rings is 28.9 (2)°. In the crystal, molecules are packed in layers parallel to the b axis in which they are connected via weak intermolecular C-H...O contacts. Face-to-face π-π interactions also exist between the benzene rings of adjacent molecules, with centroid-centroid and plane-to-plane shift distances of 3.8597 (14) and 1.843 (2) Å, respectively.
Methyl 3',4',5'-trimethoxybiphenyl-4-carboxylate
2013
In the title compound, C17H18O5, the dihedral angle between the benzene rings is 31.23 (16)°. In the crystal, the molecules are packed in an antiparallel fashion in layers along the a axis. In each layer, very weak C-H...O hydrogen bonds occur between the methoxy and methyl ester groups. Weak C-H...[pi] interactions between the 4'- and 5'-methoxy groups and neighbouring benzene rings [methoxy-C-ring centroid distances = 4.075 and 3.486 Å, respectively] connect the layers.
Poly[[myy-N,N'-bis(2-hydroxyethyl)-N,N,N',N'-tetramethylpropane-1,3-diaminium-kappa2O:O']tetra-myy-bromido-dibromidodimanganese(II)]
2012
The asymmetric unit of the title three-dimensional coordination polymer, [Mn2Br6(C11H28N2O2)]n, consists of one MnII cation, half of a dicationic N,N0 -bis(2-hydroxyethyl)- N,N,N0 ,N0 -tetramethylpropane-1,3-diaminium ligand (L) (the other half being generated by a twofold rotation axis), and three bromide ions. The MnII cation is coordinated by a single L ligand via the hydroxy O atom and by five bromide ions, resulting in a distorted octahedral MnBr5O coordination geometry. Four of the bromide ions are bridging to two adjacent MnII atoms, thereby forming polymeric chains along the a and b axes. The L units act as links between neighbouring Mn—(-Br)2—Mn chains, also forming a polymeric con…
N-{4-[(3-Methylphenyl)sulfamoyl]phenyl}benzamide
2011
In the title compound, C20H18N2O3S, the dihedral angle between the central benzene ring and the amide group is 24.1 (3) and that between this ring and the aromatic ring of the tolyl group is 68.2 (16). In the crystal, adjacent molecules are linked by N—HO hydrogen bonds into a linear chain running along [100]. Weak C—HO contacts also occur. Extensive weak – interactions exist from both face-to-face and face-to-edge interactions occur between the aromatic rings [centroid–centroid distances = 3.612 (2) and 4.843 (2) A˚ ]. Related peerReviewed
A method for measuring wetting and swelling of bentonite using X-ray imaging
2022
A non-invasive method based on X-ray imaging for measuring deformation and water transport in wetting and swelling bentonite samples is introduced. Sequential X-ray images taken of the samples were used to calculate the attenuation coefficient and deformation. These results, together with careful calibration, allowed finding the dry density and water content distributions and their temporal evolution in the wetting and swelling samples. A specific correction technique, based on regularly taking reference X-ray images of aluminum plates of varying thickness, was developed and used to take into account X-ray beam instabilities and thus to improve the accuracy of density analysis. Large deform…
1,1,4,4-Tetramethylpiperazinediium dibromide
2009
A small quantity of the title compound, C8H20N22+·2Br−, was formed as a by-product in a reaction between a diamine and an alkyl bromide. The asymmetric unit contains half of a centrosymmetric dication and a bromide anion. In the crystal, weak intermolecular C—H...Br hydrogen bonds consolidate the crystal packing.
MbCo in Saccharide Solid Amorphous Systems: A Combined FTIR and SAXS Study
2011
Saccharides, and in particular trehalose, are known for their efficiency in protecting biostructures against environmental stress [1], although the preservation mechanism is still debated. Experiments and simulations [2,3] on carboxy-myoglobin (MbCO) showed that the protein dynamics is highly inhibited in dry trehalose matrices, the inhibition being dependent on the water content. In these conditions, a mutual protein-matrix structural and dynamic influence is observed.Here we report a combined FTIR and SAXS study on MbCO embedded in dry amorphous matrices of trehalose and sucrose. FTIR measurements were performed at different protein/sugar ratios, focussing on the stretching band of the bo…
Analysis of microtomographic images of porous heterogeneous materials
2015
In this work, we study the phases of image processing chain of microtomographic imag- ing in order to obtain reliable results while optimizing the time spent on denoising and segmentation. We consider that the decisions made at the early phases of the processing chain are most important and the selection made there essentially determine the overall quality of imaging process. We also compare here various denoising method qualita- tively, however, we think that the pure noise removal ability is not the only requirement for noise removal in microtomographic images. By proper denoising we can affect selec- tion of segmentation methods and, thus, also the quality of the analysis. Additionally, …
Entrapment of a linear water pentamer into a uranyl-salophen dimer in the solid state
2019
In the solid state, uranyl-salophen complex 1, decorated with bipyridyl sidearms, self-assembles from moist acetonitrile into dimeric species displaying a confined water pentamer, as observed by X-...
Diammine{N-[2-(hydroxyimino)propionyl]-N'-[2-(oxidoimino)propionyl]propane-1,3-diaminido-κ4 N,N',N'',N'''}iron(III)
2012
In the title compound, [Fe(C9H13N4O4)(NH3)2], the FeIII atom, lying on a mirror plane, is coordinated by four N atoms of a triply deprotonated tetradentate N-[2-(hydroxyimino)- propionyl]-N0 -[2-(oxidoimino)propionyl]propane-1,3-diaminide ligand in the equatorial plane and two N atoms of two ammonia molecules at the axial positions in a distorted octahedral geometry. A short intramolecular O—HO hydrogen bond between the cis-disposed oxime O atoms stabilizes the pseudo-macrocyclic configuration of the ligand. In the crystal, molecules are linked by N—HO hydrogen bonds into a three-dimensional network. The ligand has a mirror-plane symmetry. One of the methylene groups of the propane bridge i…