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Subtleties in crystal structure solution from powder diffraction data using simulated annealing: ranitidine
1Department of Physics and Astronomy, State University of New York at Stony Brook, Stony Brook, New York 11794-3800, USA.
Journal of Pharmaceutical Sciences
|January 18, 2003
Summary
Direct space methods can now solve crystal structures from powder data, revealing subtle conformational disorders. This study demonstrates their effectiveness using ranitidine HCl, confirming known disorder from powder diffraction.
Area of Science:
- Crystallography
- Materials Science
- Structural Chemistry
Background:
- Advances in crystallographic computing and high-resolution diffraction data enable powder diffraction structure solution.
- Direct space methods require accurate initial molecular models for successful structure determination.
Purpose of the Study:
- To assess the applicability of direct space methods for identifying unknown conformational disorder in crystal structures.
- To validate the use of powder diffraction data for revealing subtle molecular conformational subtleties.
Main Methods:
- Utilized direct space methods with simulated annealing for crystal structure redetermination.
- Employed powder diffraction data for structural analysis.
- Used ranitidine HCl, a compound with known conformational disorder, as a test case.
Main Results:
- Successfully redetermined the crystal structure of ranitidine HCl from powder data.
- The conformational disorder present in ranitidine HCl was clearly revealed by the direct space method.
- Demonstrated the capability of powder diffraction to uncover complex structural features.
Conclusions:
- Direct space methods are effective in solving crystal structures from powder diffraction data.
- These methods are capable of identifying and characterizing conformational disorder not initially known.
- Powder diffraction, combined with advanced computational techniques, offers a powerful approach for detailed structural analysis.