scholarly journals Unique and Effective Characterization of Space Groups in Computer Applications

10.5772/50179 ◽  
2012 ◽  
Author(s):  
Kazimierz Str
Keyword(s):  
Computer Applications ◽  
Space Groups

Conformational differences and intermolecular C—H...N interactions in three polymorphs of a bis(pyridinyl)-substituted benzimidazole

2016 ◽  
Vol 72 (11) ◽  
pp. 867-874 ◽  
Author(s):  
David K. Geiger ◽  
Matthew R. DeStefano
Keyword(s):  
Dft Calculations ◽  
Intermolecular Interactions ◽  
Crystal Engineering ◽  
Density Functional ◽  
Molecular Conformation ◽  
Molecular Structures ◽  
Acta Cryst ◽  
Space Groups ◽  
Polymorphic Forms

The structural characterization of several polymorphic forms of a compound allow the interplay between molecular conformation and intermolecular interactions to be studied, which can contribute to the development of strategies for the rational preparation of materials with desirable properties and the tailoring of intermolecular interactions to produce solids with predictable characteristics of interest in crystal engineering. The crystal structures of two new polymorphs of 5,6-dimethyl-2-(pyridin-2-yl)-1-[(pyridin-2-yl)methyl]-1H-benzimidazole, C20H18N4, are reported. The previously reported polymorph, (1) [Geiger & DeStefano (2014).Acta Cryst.E70, o365], exhibits the space groupC2/c, whereas polymorphs (2) and (3) presented here are in thePnmaandP\overline{1} space groups, respectively. The molecular structures of the three forms differ in their orientations of the 2-(pyridin-2-yl)- and 1-[(pyridin-2-yl)methyl]- substituents. Density functional theory (DFT) calculations show that the relative energies of the molecule in the three conformations follows the order (1) < (2) < (3), with a spread of 10.6 kJ mol−1. An analysis of the Hirshfeld surfaces shows that the three polymorphs exhibit intermolecular C—H...N interactions, which can be classified into six types. Based on DFT calculations involving pairs of molecules having the observed interactions, the C—H...N energy in the systems explored is approximately −11.2 to −14.4 kJ mol−1.

Preparation and Characterization of the New Y257 Superconductors

2013 ◽  
Vol 770 ◽  
pp. 22-25 ◽  
Author(s):  
Thitipong Kruaehong
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Critical Temperature ◽  
Solid State ◽  
Superconducting Phase ◽  
Lattice Parameters ◽  
Peritectic Temperature ◽  
Space Group ◽  
Space Groups

The new Y257 superconductor in YBaCuO family was synthesized by standard solid state reaction. The Y257 samples were measured the critical temperature (Tc) by the four-probes method that found at 90 K. The XRD technique and FULLPROF program were used to determine the lattice parameters, space group and phase compositions. It was found that the Y257 exhibited in both of superconducting and non-superconducting phase. The Pmmm space group was fit well on superconducting phase with the lattice parameters as a=3.8108 Å, b=3.8544 Å and c=26.4967 Å. The non-superconducting phase exhibited in two space groups of Pccm (a=12.9770 Å, b=20.54780 Å and c=11.3530 Å) and Im-3m (a= 18.2104 Å, b=18.2104 Å and c=18.2104 Å). The peritectic temperature at 976.73°C was measured by differential thermal analysis.

scholarly journals Structural Insights of Three 2,4-Disubstituted Dihydropyrimidine-5-carbonitriles as Potential Dihydrofolate Reductase Inhibitors

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3286
Author(s):  
Lamya H. Al-Wahaibi ◽  
Althaf Shaik ◽  
Mohammed A. Elmorsy ◽  
Mohammed S. M. Abdelbaky ◽  
Santiago Garcia-Granda ◽  
...  
Keyword(s):  
Water Molecule ◽  
Dihydrofolate Reductase ◽  
Crystal Packing ◽  
Docking Simulation ◽  
X Ray Diffraction ◽  
Space Groups ◽  
Reductase Inhibitors ◽  
Inhibitory Potential ◽  
Human Dihydrofolate Reductase

In this report, we describe the structural characterization of three 2,4-disubstituted-dihydropyrimidine-5-carbonitrile derivatives, namely 2-{[(4-nitrophenyl)methyl]sulfanyl}-6-oxo-4-propyl-1,6-dihydropyrimidine-5-carbonitrile 1, 4-(2-methylpropyl)-2-{[(4-nitrophenyl)methyl]sulfanyl}-6-oxo-1,6-dihydropyrimidine-5-carbonitrile 2, and 2-[(2-ethoxyethyl)sulfanyl]-6-oxo-4-phenyl-1,6-dihydropyrimidine-5-carbonitrile monohydrate 3. An X-ray diffraction analysis revealed that these compounds were crystallized in the centrosymmetric space groups and adopt an L-shaped conformation. One of the compounds (3) crystallized with a water molecule. A cyclic motif (R22(8)) mediated by N–H···O hydrogen bond was formed in compounds 1 and 2, whereas the corresponding motif was not favorable, due to the water molecule, in compound 3. The crystal packing of these compounds was analyzed based on energy frameworks performed at the B3LYP/6-31G(d,p) level of theory. Various inter-contacts were characterized using the Hirshfeld surface and its associated 2D-fingerprint plots. Furthermore, a molecular docking simulation was carried out to assess the inhibitory potential of the title compounds against the human dihydrofolate reductase (DHFR) enzyme.

Structural characterization of Cd3(O3PC2H4CO2)2·2H2O from in-house X-ray powder data and NMR

2005 ◽  
Vol 61 (6) ◽  
pp. 669-674 ◽  
Author(s):  
Naima Bestaoui ◽  
Xiang Ouyang ◽  
Florence Fredoueil ◽  
Bruno Bujoli ◽  
Abraham Clearfield
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Structural Characterization ◽  
Title Compound ◽  
Solid State Nmr ◽  
Hydrothermal Reaction ◽  
X Ray ◽  
Space Groups ◽  
Nmr Data

The title compound poly[[bis(μ-2-carboxylatoethylphosphonato)cadmium] dihydrate], Cd3(O3PC2H4CO2)2·2H2O, was prepared by a hydrothermal reaction and its crystal structure determined from in-house powder data. The structure was solved in both P21/c and P21 space groups. The refinement converged with Rp = 0.1046, R wp = 0.1378 and Rf = 0.0763 in P21/c. However, the solid-state NMR data could not be explained. The structure was then solved in P21 and the refinement converged with Rp = 0.0750, R wp = 0.1022 and Rf = 0.0409 and satisfied the NMR requirements.

scholarly journals Purification, crystallization and preliminary X-ray diffraction analysis of inner membrane complex (IMC) subcompartment protein 1 (ISP1) fromToxoplasma gondii

2012 ◽  
Vol 68 (7) ◽  
pp. 832-834 ◽  
Author(s):  
Michelle L. Tonkin ◽  
Shannon Brown ◽  
Josh R. Beck ◽  
Peter J. Bradley ◽  
Martin J. Boulanger
Keyword(s):  
Diffraction Analysis ◽  
X Ray Diffraction ◽  
Inner Membrane ◽  
Crystal Forms ◽  
X Ray ◽  
Space Groups ◽  
Membrane Complex ◽  
Specific Proteins ◽  
Inner Membrane Complex

The protozoan parasites of the Apicomplexa phylum are devastating global pathogens. Their success is largely due to phylum-specific proteins found in specialized organelles and cellular structures. The inner membrane complex (IMC) is a unique apicomplexan structure that is essential for motility, invasion and replication. The IMC subcompartment proteins (ISP) have recently been identified inToxoplasma gondiiand shown to be critical for replication, although their specific mechanisms are unknown. Structural characterization ofTgISP1 was pursued in order to identify the fold adopted by the ISPs and to generate detailed insight into how this family of proteins functions during replication. An N-terminally truncated form ofTgISP1 was purified fromEscherichia coli, crystallized and subjected to X-ray diffraction analysis. Two crystal forms ofTgISP1 belonging to space groupsP4132 orP4332 andP212121diffracted to 2.05 and 2.1 Å resolution, respectively.

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