Powder X-ray diffraction of fluorometholone, C_(22)H_(29)FO_4

摘要

Commercial fluorometholone, CAS #426-13-1, crystallizes in the monoclinic space group P2(1) (#4) with a = 6.40648(2), b = 13.43260(5), c = 11.00060(8) angstrom, beta = 92.8203(5)degrees, V = 945.517(5) angstrom(3), and Z = 2. A reduced cell search in the Cambridge Structural Database yielded one previous structure determination, using single-crystal data at 292 K. In this work, the sample was ordered from the United States Pharmacopeial Convention (Lot # R032K0) and analyzed as-received. The room temperature (295 K) crystal structure was refined using synchrotron (lambda = 0.412826 angstrom) powder diffraction data and optimized using density functional theory (DFT) techniques. Hydrogen positions were included as a part of the structure and were re-calculated during the refinement. The diffraction data were collected on beamline 11-BM at the Advanced Photon Source, Argonne National Laboratory, and the powder X-ray diffraction pattern of the compound has been submitted to ICDD (R) for inclusion in the Powder Diffraction File (TM). The agreement of the Rietveld-refined and DFT-optimized structures is excellent; the root-mean-square Cartesian displacement is 0.060 angstrom. In addition to the O-H center dot center dot center dot O hydrogen bonds observed by Park et al. (Park, Y. J., Lee, M. Y., and Cho, S. I. (1992). "Fluorometholone," J. Korean Chem. Soc. 36, 812-817), C-H center dot center dot center dot O hydrogen bonds contribute to the crystal energy. (C) 2020 International Centre for Diffraction Data.