129Xe NMR Study of the Framework Flexibility of the Porous Hybrid MIL-53(Al)

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• 作者：Marie-Anne Springuel-Huet ; Andrei Nossov ; Ziad Adem ; Flavien Guenneau ; Christophe Volkringer ; Thierry Loiseau ; Grard Frey ; Antoine Gdon
• 刊名：Journal of the American Chemical Society
• 出版年：2010
• 出版时间：August 25, 2010
• 年：2010
• 卷：132
• 期：33
• 页码：11599-11607
• 全文大小：383K
• 年卷期：v.132,no.33(August 25, 2010)
• ISSN：1520-5126

文摘

The metal−organic framework MIL-53 exhibits a structural transition between two possible porous structures, so-called large-pore (lp) and narrow-pore (np) forms, depending on the temperature or when guest molecules are adsorbed. ¹²⁹Xe NMR has been used to study the lp → np transition induced by the adsorption of xenon as revealed by the adsorption isotherms. The NMR spectra show that the two structures, characterized by two distinct lines, coexist for xenon pressures above 5 × 10⁴ Pa at room temperature, but a complete transformation is achieved when the temperature is decreased. An original interpretation of the NMR results allowed us to quantify the rate of the structural transformation. In particular, at room temperature, we have shown that 28% of the channels remain open. Two possible interpretations of the hysteresis observed in the chemical shift variation versus xenon pressure are proposed.