A Computational and Experimental Approach Linking Disorder, High-Pressure Behavior, and Mechanical Properties in UiO Frameworks
A Computational and Experimental Approach Linking Disorder, High-Pressure Behavior, and Mechanical Properties in UiO Frameworks
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连接 UiO 框架中的无序、高压行为和机械性能的计算和实验方法
DOI：
10.1002/ange.201509352
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发表时间：
2016
影响因子：
--
通讯作者：
Hobday C
中科院分区：
文献类型：
--
作者：
Hobday C
虽然许多金属有机骨架具有用作功能材料所需的化学稳定性，但它们往往缺乏工业应用所需的物理强度。本文采用单晶纳米压痕、高压X射线衍射、密度泛函理论计算和第一性原理分子动力学等方法研究了两种UIO拓扑结构的UIO-67([Zr6O4(OH)4(Bpdc)6]，bpdc：4，4‘-联苯二羧酸盐)和UiO-ABDC([Zr6O4(OH)4(Abdc)6]，ABDC：4，4’-偶氮苯二甲酸盐)的力学性能。随着压力的增加，UIO-67和UIO-ABDC在钻石顶压室中填充甲醇分子时都被发现是不可压缩的。这两种情况下的稳定性都归因于动态连接子的紊乱。与弹性模数较大的UIO-67相比，UIO-ABDC的重氮键具有局部位置无序，与UIO-67相比，这一点连同其较长的性质，也降低了骨架压缩和稳定其抵抗直接压缩的能力。因此，在UIO-MOF的合成中使用非线性连接物可产生在较大压力范围内具有更高刚性机械性能的MOF。
Whilst many metal–organic frameworks possess the chemical stability needed to be used as functional materials, they often lack the physical strength required for industrial applications. Herein, we have investigated the mechanical properties of two UiO‐topology Zr‐MOFs, the planar UiO‐67 ([Zr6O4(OH)4(bpdc)6], bpdc: 4,4′‐biphenyl dicarboxylate) and UiO‐abdc ([Zr6O4(OH)4(abdc)6], abdc: 4,4′‐azobenzene dicarboxylate) by single‐crystal nanoindentation, high‐pressure X‐ray diffraction, density functional theory calculations, and first‐principles molecular dynamics. On increasing pressure, both UiO‐67 and UiO‐abdc were found to be incompressible when filled with methanol molecules within a diamond anvil cell. Stabilization in both cases is attributed to dynamical linker disorder. The diazo‐linker of UiO‐abdc possesses local site disorder, which, in conjunction with its longer nature, also decreases the capacity of the framework to compress and stabilizes it against direct compression, compared to UiO‐67, characterized by a large elastic modulus. The use of non‐linear linkers in the synthesis of UiO‐MOFs therefore creates MOFs that have more rigid mechanical properties over a larger pressure range.