Impact of Molecular Speciation on Crystal Nucleation in Polymorphic Systems: The Conundrum of Glycine and Molecular 'Self Poisoning
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- 作者：Christopher S. Towler ; Roger J. Davey ; Robert W. Lancaster ; and Christopher J. Price
- 刊名：Journal of the American Chemical Society
- 出版年：2004
- 出版时间：October 20, 2004
- 年：2004
- 卷：126
- 期：41
- 页码：13347 - 13353
- 全文大小：656K
- 年卷期：v.126,no.41(October 20, 2004)
- ISSN：1520-5126
文摘
The polymorphism of the simple amino acid glycine has been known for almost a century. It isalso known that in aqueous solutions, at the isoelectric point (pI 5.9), the metastable 
polymorph crystallizes,while the stable 
form of glycine only nucleates at high and low pH. Despite the importance of understandingthe process by which crystals nucleate, the solution and solid-state chemistry underlying this simpleobservation have never been explored. In this contribution, we have combined solution chemistry,crystallization, and crystallographic data to investigate the mechanisms by which this effect occurs. It isconcluded that solution speciation and the consequent interactions between charged species and developingcrystal nuclei determine the structural outcome of the crystallization process.
polymorph crystallizes,while the stable form of glycine only nucleates at high and low pH. Despite the importance of understandingthe process by which crystals nucleate, the solution and solid-state chemistry underlying this simpleobservation have never been explored. In this contribution, we have combined solution chemistry,crystallization, and crystallographic data to investigate the mechanisms by which this effect occurs. It isconcluded that solution speciation and the consequent interactions between charged species and developingcrystal nuclei determine the structural outcome of the crystallization process.