Solving molecular crystal structures from laboratory X-ray powder diffraction data with DASH: the state of the art and challenges

A.J. Florence, N. Shankland, K. Shankland, W.I.F. David, E. Pidcock, X. Xu, A. Johnston, A.R. Kennedy, P.J. Cox, J.S.O. Evans, G. Steele, S.D. Cosgrove, C.S. Frampton

Research output: Contribution to journalArticle

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Abstract

The crystal structures of 35 molecular compounds have been redetermined from laboratory monochromatic capillary transmission X-ray powder diffraction data using the simulated-annealing approach embodied within the DASH structure solution package. The compounds represent industrially relevant areas (pharmaceuticals; metal coordination compounds; nonlinear optical materials; dyes) in which the research groups in this multi-centre study are active. The molecules were specifically selected to form a series within which the degree of structural complexity (i.e. degrees of freedom in the global optimization) increased systematically, the degrees of freedom increasing with increasing number of optimizable torsion angles in the structural model and with the inclusion of positional disorder or multiple fragments (counterions; crystallization solvent; Z' > 1). At the lower end of the complexity scale, the structure was solved with excellent reproducibility and high accuracy. At the opposite end of the scale, the more complex search space offered a significant challenge to the global optimization procedure and it was demonstrated that the inclusion of modal torsional constraints, derived from the Cambridge Structural Database, offered significant benefits in terms of increasing the frequency of successful structure solution by restricting the magnitude of the search space in the global optimization.
Original languageEnglish
Pages (from-to)249-259
Number of pages10
JournalJournal of Applied Crystallography
Volume38
Issue number2
DOIs
Publication statusPublished - Apr 2005

Fingerprint

Molecular crystals
Powder Diffraction
Global optimization
Molecular Structure
X-Ray Diffraction
X ray powder diffraction
Molecular structure
Crystal structure
Structural Models
Crystallization
Coloring Agents
Optical materials
Metals
Databases
Simulated annealing
Torsional stress
Research
Pharmaceutical Preparations
Molecules

Keywords

  • crystal structures
  • molecular compounds
  • X-ray powder diffraction
  • DASH
  • crystallization solvent
  • modal torsional constraints

Cite this

Florence, A.J. ; Shankland, N. ; Shankland, K. ; David, W.I.F. ; Pidcock, E. ; Xu, X. ; Johnston, A. ; Kennedy, A.R. ; Cox, P.J. ; Evans, J.S.O. ; Steele, G. ; Cosgrove, S.D. ; Frampton, C.S. / Solving molecular crystal structures from laboratory X-ray powder diffraction data with DASH: the state of the art and challenges. In: Journal of Applied Crystallography. 2005 ; Vol. 38, No. 2. pp. 249-259.
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Florence, AJ, Shankland, N, Shankland, K, David, WIF, Pidcock, E, Xu, X, Johnston, A, Kennedy, AR, Cox, PJ, Evans, JSO, Steele, G, Cosgrove, SD & Frampton, CS 2005, 'Solving molecular crystal structures from laboratory X-ray powder diffraction data with DASH: the state of the art and challenges', Journal of Applied Crystallography, vol. 38, no. 2, pp. 249-259. https://doi.org/10.1107/S0021889804032662

Solving molecular crystal structures from laboratory X-ray powder diffraction data with DASH: the state of the art and challenges. / Florence, A.J.; Shankland, N.; Shankland, K.; David, W.I.F.; Pidcock, E.; Xu, X.; Johnston, A.; Kennedy, A.R.; Cox, P.J.; Evans, J.S.O.; Steele, G.; Cosgrove, S.D.; Frampton, C.S.

In: Journal of Applied Crystallography, Vol. 38, No. 2, 04.2005, p. 249-259.

Research output: Contribution to journalArticle

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