Oswald, I D H and Allan, D R and Day, G M and Motherwell, W D S and Parsons, S (2005) Realizing predicted crystal structures at extreme conditions : the low-temperature and high-pressure crystal structures of 2-chlorophenol and 4-fluorophenol. Crystal Growth and Design, 5 (3). pp. 1055-1071. ISSN 1528-7483Full text not available in this repository. (Request a copy from the Strathclyde author)
A crystal of 2-chlorophenol was grown from the liquid at ambient pressure by laser-assisted zone refinement; 4-fluorophenol was crystallized from ethanol. Different polymorphs were obtained at high pressure by compression of the liquids in a Merrill-Bassett diamond-anvil cell (crystallization pressures 0.12 and 0.28 GPa, respectively). The structures of all phases are characterized by OH---OH hydrogen-bond formation. In the ambient-pressure polymorph of 2-chlorophenol, a hydrogen-bonded chain is formed about a 32 screw-axis; the ambient-pressure phase of 4-fluorophenol contains hexameric rings located on 3 sites. In crystallizing in high-symmetry space groups, these two compounds conform to typical behavior for bulky monoalcohols. By contrast, at high-pressure both compounds form zigzag chains disposed about 21 screw-axes, behavior more characteristic of small monoalcohols. The halophenol moiety thus behaves as a bulky group at ambient pressure but a small group at high pressure. We show that Crystal Structure Prediction methodologies reproduce all four phases, even though the potentials used were developed using ambient-pressure data. This is especially encouraging as the ambient-pressure phase of 2-chlorophenol contains three molecules in the asymmetric unit, while the high-pressure phase of 4-fluorophenol is disordered.
|Keywords:||X-ray diffraction, distributed multipole analysis, intermolecular force-field, small organic-molecules, polyatomic-molecules, database, polymorphs, accurate, ethanol, energy, Pharmacy and materia medica, Materials Science(all), Chemistry(all), Condensed Matter Physics|
|Subjects:||Medicine > Pharmacy and materia medica|
|Department:||Faculty of Science > Strathclyde Institute of Pharmacy and Biomedical Sciences|
|Depositing user:||Pure Administrator|
|Date Deposited:||01 Jul 2011 14:56|
|Last modified:||27 Apr 2016 16:49|