Highly unusual triangular crystals of theophylline: The influence of solvent on the growth rates of polar crystal faces
Highly unusual triangular crystals of theophylline: The influence of solvent on the growth rates of polar crystal faces
A noteworthy feature of the compound theophylline is that it forms crystals with a triangular habit, an extremely rare phenomenon for an organic molecule. Here, we investigate the formation of these crystals, comprised of the polymorph Form II (Pna21), and demonstrate that the triangles are obtained from solvents which are highly hydrophobic, or which have a hydrogen bond acceptor group and no hydrogen bond donor group. The formation of the triangular crystal habit is rationalized on the basis of the way such solvents interact with the inequivalent (001) and (00-1) polar crystal faces of Form II. Interactions are significantly stronger at one face than the other, inhibiting growth in one direction and limiting crystal growth to a single, triangle shaped, growth sector. This rationalization also enabled interesting surface features observed by atomic force microscopy to be interpreted. Furthermore, we report a second, previously unreported, type of triangular crystal of theophylline for which the angle at the tip of the triangle is obtuse rather than acute. These crystals are proposed, with the aid of transmission electron microscopy and crystal structure prediction, to be a new polymorphic form of theophylline
1-10
Eddleston, Mark D.
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Hejczyk, Katarzyna E.
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Cassidy, Andrew M.C.
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Thompson, H P.G.
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Day, Graeme M.
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Jones, William
3173abf0-1cfa-45f0-996e-2586b385c21e
7 April 2015
Eddleston, Mark D.
01211ad8-8115-43de-914c-6501d1d4c584
Hejczyk, Katarzyna E.
de9b9785-9e41-4816-a309-982b3347a429
Cassidy, Andrew M.C.
f6df7830-20e8-4644-b07a-f741b31148cf
Thompson, H P.G.
8e594b1a-ef20-453c-b312-f230bb4989ba
Day, Graeme M.
e3be79ba-ad12-4461-b735-74d5c4355636
Jones, William
3173abf0-1cfa-45f0-996e-2586b385c21e
Eddleston, Mark D., Hejczyk, Katarzyna E., Cassidy, Andrew M.C., Thompson, H P.G., Day, Graeme M. and Jones, William
(2015)
Highly unusual triangular crystals of theophylline: The influence of solvent on the growth rates of polar crystal faces.
Crystal Growth & Design, .
(doi:10.1021/acs.cgd.5b00295).
Abstract
A noteworthy feature of the compound theophylline is that it forms crystals with a triangular habit, an extremely rare phenomenon for an organic molecule. Here, we investigate the formation of these crystals, comprised of the polymorph Form II (Pna21), and demonstrate that the triangles are obtained from solvents which are highly hydrophobic, or which have a hydrogen bond acceptor group and no hydrogen bond donor group. The formation of the triangular crystal habit is rationalized on the basis of the way such solvents interact with the inequivalent (001) and (00-1) polar crystal faces of Form II. Interactions are significantly stronger at one face than the other, inhibiting growth in one direction and limiting crystal growth to a single, triangle shaped, growth sector. This rationalization also enabled interesting surface features observed by atomic force microscopy to be interpreted. Furthermore, we report a second, previously unreported, type of triangular crystal of theophylline for which the angle at the tip of the triangle is obtuse rather than acute. These crystals are proposed, with the aid of transmission electron microscopy and crystal structure prediction, to be a new polymorphic form of theophylline
Text
Revised Draft FinalD in Template Triangular Crystals.pdf
- Accepted Manuscript
More information
Accepted/In Press date: 7 April 2015
Published date: 7 April 2015
Organisations:
Computational Systems Chemistry
Identifiers
Local EPrints ID: 376031
URI: http://eprints.soton.ac.uk/id/eprint/376031
ISSN: 1528-7483
PURE UUID: 4fbdc155-73ad-4563-b92e-cf40226830a5
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Date deposited: 23 Apr 2015 08:42
Last modified: 15 Mar 2024 03:44
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Contributors
Author:
Mark D. Eddleston
Author:
Katarzyna E. Hejczyk
Author:
Andrew M.C. Cassidy
Author:
H P.G. Thompson
Author:
William Jones
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