Structure determination of a steroid directly from powder diffraction data†

Kariuki, Benson M.; Psallidas, Katerina; Harris, Kenneth D. M.; Johnston, Roy L.; Lancaster, Robert W.; Staniforth, Susan E.; Cooper, Simon M.

doi:10.1039/a904702f

Cited by 65 publications

(28 citation statements)

References 14 publications

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“…It has become straightforward to follow changes as a function of temperature, pressure, and gaseous environment while maintaining the signal quality throughout the duration of the test . The following example shows the usefulness of the powder diffractometer with a hot stage that allows for in‐situ heating and controlled ambient.…”

Section: Theorymentioning

confidence: 99%

Experimental methods in chemical engineering: X‐ray diffraction spectroscopy—XRD

et al. 2020

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X-ray diffraction (XRD) analysis identifies the long-range order (ie, the structure) of crystalline materials and the short-range order of non-crystalline materials. From this information we deduce lattice constants and phases, average grain size, degree of crystallinity, and crystal defects. Advanced XRD provides information about strain, texture, crystalline symmetry, and electron density. When radiation impinges upon a solid, coherent scattering of the radiation by periodically spaced atoms results in scattered beams that produce spot patterns from single crystalline samples and ring patterns from polycrystalline samples. The pattern, intensities of the diffraction maxima (peaks or lines), and their position (Bragg angle θ or interplanar spacing d hkl ), correlate to a specific crystal structure. In 2016 and 2017 close to 100 000 articles mention XRD-more than any other analytical technique, and it was the top analytical technique of researchers that published in Can. J. Chem. Eng. A bibliographic analysis based on the Web of Science groups articles referring to XRD into five clusters: the largest cluster includes research on nanoparticles, thin films, and optical properties; composites, electro-chemistry, and synthesis are topics of the second largest cluster; crystal morphology and catalysis are next; photocatalysis and solar cells comprise the fourth largest cluster; and, waste water is among the topics of the cluster with the least number of occurrences. Researchers publishing in Can. J. Chem. Eng. focus most of the XRD analyses to characterize polymers, nanocomposite materials, and catalysts. K E Y W O R D Scrystallinity, Debye-Scherrer method, limit of quantification, nanoparticle, XRD

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Section: Theorymentioning

confidence: 99%

Experimental methods in chemical engineering: X‐ray diffraction spectroscopy—XRD

et al. 2020

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“…This method is based on the Rietveld analysis in which the effect of the preferred orientation of crystallites on diffraction intensity can be corrected using an appropriate preferred orientation function and the lattice disorder in crystals can be evaluated by peak width parameters (11,12). The Rietveld method is basically a method for crystal structure analysis using powder diffraction data, and it has also been applied to the various fields of crystal sciences (13,14). In the future, the pattern fitting procedure can be used to obtain many characteristics of crystals simultaneously, such as the lattice disorder of crystals, preferred orientation of crystallites, lattice constants, etc.…”

Section: Introductionmentioning

confidence: 99%

Crystallization Kinetics of Amorphous Griseofulvin by Pattern Fitting Procedure Using X-Ray Diffraction Data

2007

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“…Structure solution of 1 was carried out using the directspace strategy, [52,53] implemented by using ag enetica lgorithm (GA) in the program EAGER. [54][55][56][57][58][59][60][61] In the direct-spaces tructure solution calculations( see Supporting Information for more details), the molecular model wasd erived from the molecule in the crystal structure [49] of the carbon analogue of 1,b ut with the central C 6 ring replaced by ac entral B 3 N 3 ring. The asymmetricu nit comprised the whole moleculeo f1 with half occupancy of all atoms, and with the center of the molecule fixed at ac rystallographic inversion center.C learly,t he inversion symmetry operation creates disorder in the positions of the B and Na toms in the central ring, resulting in an occupancy of B 0.5 N 0.5 for each atomics ite in the central ring.…”

Section: Crystal Structure Determination Of Molecule 1f Rom Powder Xrmentioning

confidence: 99%

Boron–Nitrogen‐Doped Nanographenes: A Synthetic Tale from Borazine Precursors

Dosso

Battisti

Ward

et al. 2020

Chemistry A European J

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In this work, ac omprehensive account of the authors' synthetic efforts to prepareb orazino-doped hexabenzocoronenes by using the Friedel-Crafts-type electrophilic aromatic substitution is reported. Hexafluoro-functionalized aryl borazines, bearing an ortho fluoride leaving group on each of the N-and B-aryl rings,w as shown to lead to cascade-type electrophilica romatic substitution events in the stepwise CÀCbond formation, giving higher yields of borazinocoronenes than those obtained with borazine precursors bearing fluoride leavingg roups at the ortho positions of the B-aryl substituents. By using this pathway,a nu nprecedented boroxadizine-doped PAHf eaturing ag ulf-type periphery could be isolated,a nd itss tructure proven by single-crystal X-ray diffraction analysis. Mechanistic studies on the stepwise Friedel-Crafts-type cyclization suggestt hat the mechanism of the planarizationr eactionp roceeds through extension of the p system. To appraise the doping effect of the boroxadizine unit on the optoelectronic properties of topology-equivalent molecular graphenes, the all-carbon and pyrylium PAHa nalogues, all featuring ag ulf-type periphery, were also prepared. As already shown for the borazinodoped hexabenzocoronene, the replacement of the central benzene ring by its B 3 N 2 Oc ongener widens the HOMO-LUMO gap and dramaticallye nhances the fluorescence quantum yield.[a] J. Scheme1.Synthetic planarizationp rotocols for preparing borazino-doped hexabenzocoronenes 1 and 2.Figure 7. ESP surfaces mapped on the vdW surface up to an electrondensity of 0.05 electronbohr À3 for a) 11 and b) 18.Side (up) and top (bottom) view of the packingo fc )11 and d) 18.Atom colors:pink B, blue N, red O, gray C. Spacegroups: P2 1 /c and P1.

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Structure determination of a steroid directly from powder diffraction data†

Cited by 65 publications

References 14 publications

Experimental methods in chemical engineering: X‐ray diffraction spectroscopy—XRD

Experimental methods in chemical engineering: X‐ray diffraction spectroscopy—XRD

Crystallization Kinetics of Amorphous Griseofulvin by Pattern Fitting Procedure Using X-Ray Diffraction Data

Boron–Nitrogen‐Doped Nanographenes: A Synthetic Tale from Borazine Precursors

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