Time-Resolved in Situ Polymorphic Transformation from One 12-Connected Zr-MOF to Another
Time-Resolved in Situ Polymorphic Transformation from One 12-Connected Zr-MOF to Another
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DOI：
10.1021/acsmaterialslett.0c00012
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发表时间：
2020-05-04
影响因子：
11.4
通讯作者：
Farha, Omar K.
中科院分区：
文献类型：
--
作者：
Lee, Seung-Joon;Mancuso, Jenna L.;Farha, Omar K.
了解金属有机框架（MOFs）中的多晶型提供了解开MOFs结晶过程的机会，并且它能够阐明组成相同的晶体的结构-性质关系。在这里，我们提出了调制器和温度介导的多晶型转化的动力学产物从Zr-6为基础的MOF合成，EHU-30，热力学产品，UIO-66。部分溶解-重结晶过程通过原位粉末X射线衍射（PXRD）和原位H-1 NMR光谱的组合来证明，其中EHU-30在单调酸调节剂乙酸存在下加热。密度泛函理论（DFT）计算显示EHU-30多晶型物较不稳定，因为与热力学产物UiO-66中的线性连接体相比，弯曲连接体具有更高的吉布斯自由能。
Understanding polymorphism in metal-organic frameworks (MOFs) provides opportunities to unravel the process of MOF crystallization, and it enables the elucidation of structure-property relationships of compositionally identical crystals. Here, we present the modulator- and temperature-mediated polymorphic transformation of the kinetic product from Zr-6-based MOF synthesis, EHU-30, to the thermodynamic product, UiO-66. The partial dissolution-recrystallization process was demonstrated by a combination of in situ powder X-ray diffraction (PXRD) and in situ H-1 NMR spectroscopy where EHU-30 was heated in the presence of a monotopic acid modulator, acetic acid. Density functional theory (DFT) calculations show that the EHU-30 polymorph is less stable because the bent linkers have higher Gibbs free energy compared to linear linkers in the thermodynamic product, UiO-66.