Crystal structure determination using laboratory X-ray powder diffraction data in combination with global optimisation methods is a powerful approach for accessing structural details in the absence of single crystal samples.¹ That said, the use of additional information to supplement the structure determination process can be of significant value, for example to reduce the conformational search space² or confirm the location of hydrogen atoms.³  Here, we are concerned with determining the solid-state structures of a series of fluorinated ethanols with the aim of studying the molecular packing and hydrogen bonding interactions involving the solvent molecules in both pure solvent and in crystalline solvates.  We report the application of geometry optimisation using CASTEP to verify the location of hydrogen atoms in the structures obtained from the simulated annealing runs.  The optimised structures provide a more accurate description of the hydrogen bonding interactions in these materials.  Polycrystalline samples of the solvents were obtained by cooling a liquid sample held within a glass capillary in situ on a Bruker-AXS D8 powder diffractometer.  Despite rotating the capillaries during data collection, significant preferred orientation was encountered. Single crystal structures for two of the solvents studied were also obtained using high-P methods.

References

1. K. Shankland, W.I.F. David, L.B. McCusker, Ch. Baerlocher, ed., Structure Determination from Powder Diffraction Data, Oxford University Press Inc., New York, 2002.

2. I.J. Bruno, J.C. Cole, M. Kessler, Jie Luo, W.D.S. Motherwell, L.H. Purkis, B.R. Smith, R. Taylor, R. I. Cooper, S. E. Harris, A. G. Orpen, J. Chem. Inf. Comput. Sci., 44, 2133, 2004

3. C. Platteau, J. Lefebvre, F. Affouard, P. Derollez, Acta Crystallogr., B60, 453-460, 2004.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/15410 must be provided.

1. Development of continuous crystallisation processes of pharmaceutical compounds to achieve better control over final product attributes
2. Large-scale distributed computing for accelerated structure determination