Complex Polymorphic System of Gallic Acid鈥擣ive Monohydrates, Three Anhydrates, and over 20 Solvates

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• 作者：Doris E. Braun ; Rajni M. Bhardwaj ; Alastair J. Florence ; Derek A. Tocher ; Sarah L. Price
• 刊名：Crystal Growth & Design
• 出版年：2013
• 出版时间：January 2, 2013
• 年：2013
• 卷：13
• 期：1
• 页码：19-23
• 全文大小：367K
• 年卷期：v.13,no.1(January 2, 2013)
• ISSN：1528-7505

文摘

We report the structure of the fifth monohydrate of gallic acid and two additional anhydrate polymorphs and evidence of at least 22 other solvates formed, many containing water and another solvent. This unprecedented number of monohydrate polymorphs and diversity of solid forms is consistent with the anhydrate and monohydrate crystal energy landscapes, showing both a wide range of packing motifs and also some structures differing only in proton positions. By aiding the solution of structures from powder X-ray diffraction data and guiding the screening, the computational studies help explain the complex polymorphism of gallic acid. This is industrially relevant, as the three anhydrates are stable at ambient conditions but hydration/dehydration behavior is very dependent on relative humidity and phase purity.