Discovery of three polymorphs of 7-fluoroisatin reveals challenges in using computational crystal structure prediction as a complement to experimental screening

DOI: 10.1039/b714566g

Authors: Sharmarke Mohamed (University of Reading) , Sarah Barnett (Diamond Light Source) , Derek Tocher (University College London) , Sarah Price (University College London) , Kenneth Shankland (ISIS Facility) , Charlotte Leech (ISIS Facility)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Crystengcomm , VOL 10 (4) , PAGES 399-404

State: Published (Approved)
Published: January 2008

Abstract: A combined computational and experimental polymorph search was undertaken to establish the crystal forms of 7-fluoroisatin, a simple molecule with no reported crystal structures, to evaluate the value of crystal structure prediction studies as an aid to solid form discovery. Three polymorphs were found in a manual crystallisation screen, as well as two solvates. Form I (P21/c, Z? = 1), found from the majority of solvent evaporation experiments, corresponded to the most stable form in the computational search of Z? = 1 structures. Form III (P21/a, Z? = 2) is probably a metastable form, which was only found concomitantly with form I, and has the same dimeric R22(8) hydrogen bonding motif as form I and the majority of the computed low energy structures. However, the most thermodynamically stable polymorph, form II (P

Subject Areas: Chemistry


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