Thermodynamic Insight in the High-Pressure Behavior of UiO-66: Effect of Linker Defects and Linker Expansion

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• 作者：Sven M. J. Rogge ; Jelle Wieme ; Louis Vanduyfhuys ; Steven Vandenbrande ; Guillaume Maurin ; Toon Verstraelen ; Michel Waroquier ; Veronique Van Speybroeck
• 刊名：Chemistry of Materials
• 出版年：2016
• 出版时间：August 23, 2016
• 年：2016
• 卷：28
• 期：16
• 页码：5721-5732
• 全文大小：824K
• 年卷期：0
• ISSN：1520-5002

文摘

In this Article, we present a molecular-level understanding of the experimentally observed loss of crystallinity in UiO-66-type metal–organic frameworks, including the pristine UiO-66 to -68 as well as defect-containing UiO-66 materials, under the influence of external pressure. This goal is achieved by constructing pressure-versus-volume profiles at finite temperatures using a thermodynamic approach relying on ab initio derived force fields. On the atomic level, the phenomenon is reflected in a sudden drop in the number of symmetry operators for the crystallographic unit cell because of the disordered displacement of the organic linkers with respect to the inorganic bricks. For the defect-containing samples, a reduced mechanical stability is observed, however, critically depending on the distribution of these defects throughout the material, hence demonstrating the importance of judiciously characterizing defects in these materials.