scholarly journals Crystal Structure of 17α-Dihydroequilin, C18H22O2, from Synchrotron Powder Diffraction Data and Density Functional Theory

Crystals ◽  
2017 ◽  
Vol 7 (7) ◽  
pp. 218
Author(s):  
James Kaduk ◽  
Amy Gindhart ◽  
Thomas Blanton
2016 ◽  
Vol 31 (3) ◽  
pp. 176-184
Author(s):  
James A. Kaduk ◽  
Kai Zhong ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton

The crystal structure of citalopram hydrobromide has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional theory techniques. Citalopram hydrobromide crystallizes in space group P21/c (#14) with a = 10.766 45(6), b = 33.070 86(16), c = 10.892 85(5) Å, β = 90.8518(3)°, V = 3878.03(4) Å3, and Z = 8. N–H⋯Br hydrogen bonds are important to the structure, but the crystal energy is dominated by van der Waals attraction. The powder pattern was submitted to International Centre for Diffraction Data for inclusion in the Powder Diffraction File™.


2014 ◽  
Vol 70 (a1) ◽  
pp. C1442-C1442
Author(s):  
Karthikeyan Natarajan ◽  
Sathya Duraisamy ◽  
Sivakumar Kandasamy

X -ray diffraction becomes a routine process these decades for determining crystal structure of the materials. Most of the crystal structures solved nowadays is based on single crystal X-ray diffraction because it solves the crystal and molecular structures from small molecules to macro molecules without much human intervention. However it is difficult to grow single crystals of sufficient size and quality for conventional single-crystal X-ray diffraction studies. In such cases it becomes essential that structural information can be determined from powder diffraction data. With the recent developments in the direct-space approaches for structure solution, ab initio crystal structure analysis of molecular solids can be accomplished from X-ray powder diffraction data. It should be recalled that crystal structure determination from laboratory X-ray powder diffraction data is a far more difficult task than that of its single-crystal counterpart, particularly when the molecule possesses considerable flexibility or there are multiple molecules in the asymmetric unit. Salicylic acid and its derivatives used as an anti-inflammatory drug are known for its numerous medicinal applications. In our study, we synthesized mononuclear copper (II) complex of salicylate derivative. The structural characterization of the prepared compound was carried out using powder X-ray diffraction studies. Crystal structure of the compound has been solved by direct-space approach and refined by a combination of Rietveld method using TOPAS Academic V4.1. Density Functional Theory (DFT) calculations have to be carried in the solid state for the compound using GaussianW9.0 in the frame work of a generalized-gradient approximation (GGA). The geometry optimization was to be performed using B3LYP density functional theory. The atomic coordinates were taken from the final X-ray refinement cycle.


2014 ◽  
Vol 30 (1) ◽  
pp. 67-75 ◽  
Author(s):  
Joel W. Reid ◽  
James A. Kaduk ◽  
Subrahmanyam V. Garimella ◽  
John S. Tse

Synchrotron powder diffraction data from beamline 08B1-1 at the Canadian Light Source have been used to examine the structure of curcumin, a prime component of the Asian spice turmeric. Rigid body refinement, with the application of restraints on distances and angles, was performed with the Rietveld software package GSAS yielding monoclinic lattice parameters ofa= 12.6967(1) Å,b= 7.198 52(3) Å,c= 19.9533(2) Å, andβ= 95.1241(6)° (C21H20O6,Z= 4, and space groupP2/n). The refinement was compared with a recent single-crystal structure andab initioresults obtained with density functional theory calculations.


Crystals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 384 ◽  
Author(s):  
Zachary R. Butler ◽  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton

The crystal structure of fosfomycin tromethamine has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Fosfomycin tromethamine crystallizes in space group P1 (#1) with a = 6.20421(6), b = 9.00072(7), c = 10.91257(15) Å, α = 93.4645(5), β = 101.9734(3), γ = 99.9183(2)°, V = 584.285(2) Å3, and Z = 2. A network of discrete hydrogen bonds links the cations and anions into layers parallel to the ab-plane. The outer surfaces of the layers are composed of the methyloxirane rings of the anions and the methylene groups of the cations. Furthermore, 93% of the atoms are consistent with an additional (pseudo)center of symmetry. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™.


2021 ◽  
pp. 1-8
Author(s):  
Joel W. Reid ◽  
James A. Kaduk

The crystal structure of donepezil hydrochloride, form III, has been solved with FOX using laboratory powder diffraction data previously submitted to and published in the Powder Diffraction File. Rietveld refinement with GSAS yielded monoclinic lattice parameters of a = 14.3662(9) Å, b = 11.8384(6) Å, c = 13.5572(7) Å, and β = 107.7560(26)° (C24H30ClNO3, Z = 4, space group P21/c). The Rietveld-refined structure was compared to a density functional theory (DFT)-optimized structure, and the structures exhibit excellent agreement. Layers of donepezil molecules parallel to the (101) planes are maintained by columns of chloride anions along the b-axis, where each chloride anion hydrogen bonds to three donepezil molecules each.


2017 ◽  
Vol 32 (2) ◽  
pp. 140-147 ◽  
Author(s):  
Joel W. Reid ◽  
James A. Kaduk ◽  
Jeremy A. Olson

The crystal structure of Na(NH4)Mo3O10·H2O has been solved by parallel tempering using the FOX software package with synchrotron powder diffraction data obtained from beamline 08B1-1 at the Canadian Light Source. Rietveld refinement, performed with the software package GSAS, yielded orthorhombic lattice parameters of a = 13.549 82(10), b = 7.618 50(6), and c = 9.302 74(7) Å (Z = 4, space group Pnma). The structure is composed of molybdate chains running parallel to the b-axis. The Rietveld refinement results were compared with density functional theory calculations performed with CRYSTAL14, and show excellent agreement with the calculated structure.


2018 ◽  
Vol 33 (1) ◽  
pp. 49-54 ◽  
Author(s):  
Joel W. Reid ◽  
James A. Kaduk ◽  
Lidia Matei

The crystal structure of MoO2(O2)H2O has been solved by analogy with the WO2(O2)H2O structure and refined with synchrotron powder diffraction data obtained from beamline 08B1-1 at the Canadian Light Source. Rietveld refinement, performed with the software package GSAS, yielded monoclinic lattice parameters of a = 12.0417(4) Å, b = 3.87003(14) Å, c = 7.38390(24) Å, and β = 78.0843(11)° (Z = 4, space group P21/n). The structure is composed of double zigzag molybdate chains running parallel to the b-axis. The Rietveld refined structure was compared with density functional theory (DFT) calculations performed with CRYSTAL14, and show strong agreement with the DFT optimized structure.


2016 ◽  
Vol 31 (3) ◽  
pp. 205-210 ◽  
Author(s):  
Joel W. Reid ◽  
James A. Kaduk ◽  
Martin Vickers

The crystal structure of trandolapril has been solved by parallel tempering using the FOX software package with laboratory powder diffraction data submitted to and published in the Powder Diffraction File. Rietveld refinement was performed with the software package GSAS yielding orthorhombic lattice parameters of a = 19.7685(4), b = 15.0697(4), and c = 7.6704(2) Å (C24H34N2O5, Z = 4, space group P212121). The Rietveld refinement results were compared with density functional theory (DFT) calculations performed with CRYSTAL14. While the structures are similar, discrepancies are observed in the configuration of the octahydroindole ring between the Rietveld and DFT structures, suggesting the refined and calculated molecules are diastereomers.


2010 ◽  
Vol 25 (4) ◽  
pp. 322-328 ◽  
Author(s):  
P. S. Whitfield ◽  
L. D. Mitchell ◽  
Y. Le Page ◽  
J. Margeson ◽  
A. C. Roberts

The crystal structure of the mineral strontiodresserite, (Sr,Ca)Al2(CO3)2(OH)4⋅H2O, from the Francon Quarry, Montreal, Quebec, Canada, has been solved from laboratory powder diffraction data using a combination of charge-flipping and simulated annealing methods. The structure is orthorhombic in space group Pnma with a=16.0990(7), b=5.6133(3), and c=9.1804(4) Å (Z=4) and the framework of the mineral is isostructural with that of dundasite. The strontium has a coordination number of 9 and the carbonate anions form a bridge between the SrO9 polyhedra and AlO6 octahedra. The water molecule lies in a channel that runs parallel to the b axis. An ordered network of hydrogen atoms could be uniquely determined from crystal-chemical principles in the channels of strontiodresserite. Ab initio density functional theory (DFT) energy minimization of the whole structure gave results in full agreement with X-ray refinement results for nonhydrogen atoms. The stability of this model (as well as that of the corresponding model of dundasite) in the proposed Pnma space group was tested by DFT optimization in space group P1 of random small distortions of this structure. This test confirms that both minerals are isostructural, including their hydrogen-bond networks.


2018 ◽  
Vol 33 (2) ◽  
pp. 178-179
Author(s):  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton

The crystal structure of phenytoin sodium monohydrate at 295 K has been refined using synchrotron powder diffraction data, and optimized using density functional techniques.


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