Absorbing a Little Water: The Structural, Thermodynamic, and Kinetic Relationship between Pyrogallol and Its Tetarto-Hydrate

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• 作者：Doris E. Braun ; Rajni M. Bhardwaj ; Jean-Baptiste Arlin ; Alastair J. Florence ; Volker Kahlenberg ; Ulrich J. Griesser ; Derek A. Tocher ; Sarah L. Price
• 刊名：Crystal Growth & Design
• 出版年：2013
• 出版时间：September 4, 2013
• 年：2013
• 卷：13
• 期：9
• 页码：4071-4083
• 全文大小：782K
• 年卷期：v.13,no.9(September 4, 2013)
• ISSN：1528-7505

文摘

The anhydrate and the stoichiometric tetarto-hydrate of pyrogallol (0.25 mol water per mol pyrogallol) are both storage stable at ambient conditions, provided that they are phase pure, with the system being at equilibrium at a_w (water activity) = 0.15 at 25 掳C. Structures have been derived from single crystal and powder X-ray diffraction data for the anhydrate and hydrate, respectively. It is notable that the tetarto-hydrate forms a tetragonal structure with water in channels, a framework that although stabilized by water, is found as a higher energy structure on a computationally generated crystal energy landscape, which has the anhydrate crystal structure as the most stable form. Thus, a combination of slurry experiments, X-ray diffraction, spectroscopy, moisture (de)sorption, and thermo-analytical methods with the computationally generated crystal energy landscape and lattice energy calculations provides a consistent picture of the finely balanced hydration behavior of pyrogallol. In addition, two monotropically related dimethyl sulfoxide monosolvates were found in the accompanying solid form screen.