Vervoorts Pia, Keupp Julian, Schneemann Andreas, Hobday Claire L, Daisenberger Dominik, Fischer Roland A, Schmid Rochus, Kieslich Gregor
Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85748, Garching, Germany.
Computational Materials Chemistry, Ruhr University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany.
Angew Chem Int Ed Engl. 2021 Jan 11;60(2):787-793. doi: 10.1002/anie.202011004. Epub 2020 Nov 12.
Flexible metal-organic frameworks (MOFs) show large structural flexibility as a function of temperature or (gas)pressure variation, a fascinating property of high technological and scientific relevance. The targeted design of flexible MOFs demands control over the macroscopic thermodynamics as determined by microscopic chemical interactions and remains an open challenge. Herein we apply high-pressure powder X-ray diffraction and molecular dynamics simulations to gain insight into the microscopic chemical factors that determine the high-pressure macroscopic thermodynamics of two flexible pillared-layer MOFs. For the first time we identify configurational entropy that originates from side-chain modifications of the linker as the key factor determining the thermodynamics in a flexible MOF. The study shows that configurational entropy is an important yet largely overlooked parameter, providing an intriguing perspective of how to chemically access the underlying free energy landscape in MOFs.
柔性金属有机框架材料（MOFs）随着温度或（气体）压力变化呈现出很大的结构柔性，这是一种具有高度技术和科学相关性的迷人特性。柔性MOFs的定向设计需要控制由微观化学相互作用决定的宏观热力学，这仍然是一个悬而未决的挑战。在此，我们应用高压粉末X射线衍射和分子动力学模拟，以深入了解决定两种柔性柱状层MOFs高压宏观热力学的微观化学因素。我们首次确定，源自连接体侧链修饰的构型熵是决定柔性MOF热力学的关键因素。该研究表明，构型熵是一个重要但在很大程度上被忽视的参数，为如何通过化学方法探究MOFs潜在的自由能态势提供了一个有趣的视角。
