Two polymorphs of 2-ethyl-3-hydroxy-6-methylpyridinium hydrogenN-acetyl-L-glutamate from powder diffraction data

2013 ◽  
Vol 69 (12) ◽  
pp. 1549-1552 ◽  
Author(s):  
Vladimir V. Chernyshev ◽  
Sergey Y. Efimov ◽  
Ksenia A. Paseshnichenko ◽  
Andrey A. Shiryaev
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Crystal Packing ◽  
Three Dimensional ◽  
Powder Diffraction Data ◽  
Screw Axis ◽  
Dimensional Network ◽  
Polymorphic Modifications

The title salt, C8H12NO+·C7H10NO5−, crystallizes in two polymorphic modifications,viz.monoclinic (M) and orthorhombic (O). The crystal structures of both polymorphic modifications have been established from laboratory powder diffraction data. The crystal packing motifs in the two polymorphs are different, but the conformations of the anions are generally similar. InM, the anions are linked by pairs of hydrogen bonds of the N—H...O and O—H...O types into chains along theb-axis direction, and neighbouring molecules within the chain are related by the 21screw axis. The cations link these chainsviaO—H...O and N—H...O hydrogen bonds into layers parallel to (001). InO, the anions are linked by O—H...O hydrogen bonds into helices along [001], and neighbouring molecules within the helix are related by the 21screw axis. The neighbouring helical turns are linked by N—H...O hydrogen bonds. The cations link the helicesviaO—H...O and N—H...O hydrogen bonds, thus forming a three-dimensional network.

Two polymorphs of afobazole from powder diffraction data

2013 ◽  
Vol 69 (3) ◽  
pp. 299-302 ◽  
Author(s):  
Vladimir V. Chernyshev ◽  
Sanita Petkune ◽  
Andris Actins ◽  
Raimonds Auzins ◽  
Dmitry I. Davlyatshin ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Crystal Packing ◽  
Water Molecules ◽  
Powder Diffraction Data ◽  
Atmospheric Water ◽  
Anxiolytic Drug ◽  
Polymorphic Modifications

Afobazole {systematic name: 2-[2-(morpholin-4-yl)ethylsulfanyl]-1H-benzimidazole} is a new anxiolytic drug and Actins, Auzins & Petkune [(2012). Eur. Patent EP10163962] described four polymorphic modifications. In the present study, the crystal structures of two monoclinic polymorphs, 5-ethoxy-2-[2-(morpholin-4-ium-4-yl)ethylsulfanyl]-1H-benzimidazol-3-ium dichloride, C15H23N3O2S2+·2Cl−, (II) and (IV), have been established from laboratory powder diffraction data. The crystal packing and conformation of the dications in (II) and (IV) are different. In (II), there are channels in the [001] direction, which offer atmospheric water molecules an easy way of penetrating into the crystal structure, thus explaining the higher hygroscopicity of (II) compared with (IV).

scholarly journals Crystal structures of crotonaldehyde semicarbazone and crotonaldehyde thiosemicarbazone from X-ray powder diffraction data

2015 ◽  
Vol 71 (2) ◽  
pp. 168-172 ◽  
Author(s):  
Atef Arfan ◽  
Mwaffak Rukiah
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Crystal Packing ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Semicarbazide Hydrochloride

Crotonaldehyde semicarbazone {systematic name: (E)-2-[(E)-but-2-en-1-ylidene]hydrazinecarboxamide}, C5H9N3O, (I), and crotonaldehyde thiosemicarbazone {systematic name: (E)-2-[(E)-but-2-en-1-yldene]hydrazinecarbothioamide}, C5H9N3S, (II), show the sameEconformation around the imine C=N bond. Compounds (I) and (II) were obtained by the condensation of crotonaldehyde with semicarbazide hydrochloride and thiosemicarbazide, respectively. Each molecule has an intramolecular N—H...N hydrogen bond, which generates anS(5) ring. In (I), the crotonaldehyde fragment is twisted by 2.59 (5)° from the semicarbazide mean plane, while in (II) the corresponding angle (with the thiosemicarbazide mean plane) is 9.12 (5)°. The crystal packing is different in the two compounds: in (I) intermolecular N—H...O hydrogen bonds link the molecules into layers parallel to thebcplane, while weak intermolecular N—H...S hydrogen bonds in (II) link the molecules into chains propagating in [110].

Structures of three substituted arenesulfonamides from X-ray powder diffraction data using the differential evolution technique

2002 ◽  
Vol 58 (5) ◽  
pp. 823-834 ◽  
Author(s):  
Maryjane Tremayne ◽  
Colin C. Seaton ◽  
Christopher Glidewell
Keyword(s):  
Hydrogen Bonds ◽  
Differential Evolution ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Rietveld Method ◽  
Three Dimensional ◽  
Differential Evolution Algorithm ◽  
Space Structure ◽  
Powder Diffraction Data ◽  
X Ray

The structures of three substituted arenesulfonamides have been solved from laboratory X-ray powder diffraction data, using a new direct-space structure solution method based on a differential evolution algorithm, and refined by the Rietveld method. In 2-toluenesulfonamide, C7H9NO2S (I) (tetragonal I41/a, Z = 16), the molecules are linked by N—H...O=S hydrogen bonds into a three-dimensional framework. In 3-nitrobenzenesulfonamide, C6H6N2O4S (II) (monoclinic P21, Z = 2), N—H...O=S hydrogen bonds produce molecular ladders, which are linked into sheets by C—H...O=S hydrogen bonds: the nitro group does not participate in the hydrogen bonding. Molecules of 4-nitrobenzenesulfonamide, C6H6N2O4S (III) (monoclinic P21/n, Z = 4), are linked into sheets by four types of hydrogen bond, N—H...O=S, N—H...O(nitro), C—H...O=S and C—H...O(nitro), and the sheets are weakly linked by aromatic π...π stacking interactions.

Structure determination of three polymorphs of xylazine from laboratory powder diffraction data

2014 ◽  
Vol 70 (2) ◽  
pp. 342-346 ◽  
Author(s):  
Alvis Zvirgzdins ◽  
Anatolijs Mishnev ◽  
Andris Actins
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Structure Determination ◽  
Amine Hydrochloride ◽  
Stacking Interactions ◽  
Powder Diffraction Data ◽  
Amino Groups

The crystal structures of three xylazine hydrochloride [N-(2,6-dimethylphenyl)-5,6-dihydro-4H-1,3-thiaz-2-amine hydrochloride] polymorphsA,ZandXhave been solved from powder diffraction data and refined using Rietveld refinement. Data were obtained with Cu Kα radiation. All polymorphs were found to have structures withZ′ = 1 andZ= 4. All the structures determined contained strong hydrogen bonds between the amino groups and chloride anions. The crystal structures of formsAandXfeatured π–π stacking interactions.

Structural investigation of the nickel 3-methylglutarate from powder diffraction demonstrating adaptability of the inorganic skeleton of MIL-77

2005 ◽  
Vol 20 (4) ◽  
pp. 288-293 ◽  
Author(s):  
Nathalie Guillou ◽  
Carine Livage ◽  
Julienne Chaigneau ◽  
Gérard Férey
Keyword(s):  
Sodium Hydroxide ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Structural Investigation ◽  
Three Dimensional ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Dimensional Network ◽  
Cubic System ◽  
Autogenous Pressure

Ni20[(C6H8O4)20(H2O)8]∙33H2O, a new nickel(II) 3-methylglutarate, was prepared hydrothermally (180 °C, 48 h, autogenous pressure) from a 1:1.5:2:180 mixture of nickel (II) sulphate hexahydrate, 3-methylglutaric acid, sodium hydroxide, and water. It crystallizes in the cubic system (space group P4332, Z=1) with a=16.8488(5) Å and V=4783.1(4) Å3. Its structure was solved from conventional X-ray powder diffraction data. It presents a three-dimensional network of edge-sharing nickel octahedra, lined by deprotonated organic anions. This remarkable oxide network with corrugated 20-membered rings is constructed from homochiral helices. The rings intersect each other to generate large crossing channels full of water along [111].

The Use of PCs for AB Initio Structure Determination From Powder Diffraction Data

1993 ◽  
Vol 37 ◽  
pp. 21-25
Author(s):  
Michèle Louër ◽  
Daniel Louër
Keyword(s):  
Ab Initio ◽  
Crystal Structures ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Structure Determination ◽  
Rietveld Method ◽  
Three Dimensional ◽  
Powder Diffraction Data ◽  
Ab Initio Structure ◽  
Desk Computer

The determination ab initio of crystal structures from powder diffraction data has been the most striking advance of modern powder crystallography. It is a consequence of the major developments occurred in instrument resolution, powder pattern indexing and Fitting techniques, e.g. the problem of peak overlap resulting from the collapse of the three dimensional pattern into one dimensional powder diffraction data has been circumvented by the advent of the Rietveld method. A structure analysis starting from scratch involves successive stages from the collection of high quality powder diffraction data to the refinement of the atomic coordinates by the Rietveld method. Since the pioneering work by Werner and co-workers a number of crystal structures solved from powder diffraction data, collected with synchrotron and conventional sources have been reported. With the growing development of this important application of the powder method, integrated softwares for solving crystal structures are now of interest, and a number of programs are available for the analysis of the different stages of a structural study. These programs combine computer routines for the treatment of powder diffraction data and routines used in conventional structure determination from single crystal data. Most of these programs have been listed in the Powder Diffraction Program Information 1990 Program List. Owing to the efficiency of modern personal computers, solving a crystal structure ab initio from powder diffraction data can now be carried out with a desk computer.

Crystal structures of tricalcium citrates

2018 ◽  
Vol 33 (2) ◽  
pp. 98-107 ◽  
Author(s):  
James A. Kaduk
Keyword(s):  
Crystal Structures ◽  
Density Functional ◽  
Three Dimensional ◽  
Water Molecules ◽  
Calcium Citrate ◽  
Powder Diffraction Data ◽  
Coordination Polyhedra ◽  
X Ray ◽  
Calcium Supplements ◽  
Dimensional Network

The crystal structures of calcium citrate hexahydrate, calcium citrate tetrahydrate, and anhydrous calcium citrate have been solved using laboratory and synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Both the hexahydrate and tetrahydrate structures are characterized by layers of edge-sharing Ca coordination polyhedra, including triply chelated Ca. An additional isolated Ca is coordinated by water molecules, and two uncoordinated water molecules occur in the hexahydrate structure. The previously reported polymorph of the tetrahydrate contains the same layers, but only two H2O coordinated to the isolated Ca and two uncoordinated water molecules. Anhydrous calcium citrate has a three-dimensional network structure of Ca coordination polyhedra. The new polymorph of calcium citrate tetrahydrate is the major crystalline phase in several commercial calcium supplements.

The crystal structures of solvent-free alkali-metal squarates from powder diffraction data

2005 ◽  
Vol 220 (11) ◽  
Author(s):  
Robert E. Dinnebier ◽  
Hanne Nuss ◽  
Martin Jansen
Keyword(s):  
High Resolution ◽  
Alkali Metal ◽  
Crystal Structures ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Room Temperature ◽  
Solvent Free ◽  
Crystallographic Data ◽  
Powder Diffraction Data ◽  
X Ray

AbstractThe crystal structures of solvent-free lithium, sodium, rubidium, and cesium squarates have been determined from high resolution synchrotron and X-ray laboratory powder patterns. Crystallographic data at room temperature of Li

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