Discovery of spontaneous de-interpenetration through charged point-point repulsions
Discovery of spontaneous de-interpenetration through charged point-point repulsions
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DOI：
10.1016/j.chempr.2021.10.027
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发表时间：
2022-01-13
期刊：
影响因子：
23.5
通讯作者：
Farha, Omar K.
中科院分区：
文献类型：
--
作者：
Hanna, Sylvia L.;Chheda, Saumil;Farha, Omar K.
在自然界和合成系统中，通过纠缠来减少孔隙度的能量驱动是普遍存在的。这种缠结减少了催化、存储和传感等应用的宝贵内部孔隙空间。在这里，我们描述了在6倍互穿铀基金属有机骨架（MOF） nu - 133 -6中自发脱穿的发现。脱穿将NU-1303-6（14.2埃和19.8埃孔隙）转化为未互穿的大孔隙（40.7埃），孔隙率高达96.6%，孔隙体积为9.2 cm(3) g（-1）。密度泛函理论计算表明，阴离子之间带电的点-点排斥，紧密定位的铀基节点驱动这种现象。这些斥力与水分子竞争，水分子将附近的网络氢键结合在一起，有利于相互渗透。控制这些分子间力之间的相互作用可以逆转无处不在的能量平衡，从而导致热力学上有利的开孔结构。带电点-点斥力的发现可能会导致对非互穿网络设计、合成和广泛应用的重新评估。
Energetically driven reduction of porosity through entanglement is ubiquitous in nature and synthetic systems. This entanglement decreases valuable internal pore space useful for applications, such as catalysis, storage, and sensing. Here, we describe the discovery of spontaneous de-interpenetration in a 6-fold interpenetrated uranium-based metal-organic framework (MOF), NU-1303-6. De-interpenetration transforms NU-1303-6 (14.2 and 19.8 angstrom pores) to its larger pore (40.7 angstrom) non-interpenetrated counterpart, which possesses a record-high 96.6% void fraction and 9.2 cm(3) g(-1) pore volume. Density functional theory calculations reveal that charged point-point repulsions between anionic, closely positioned uranium-based nodes drive this phenomenon. These repulsions compete with water molecules that hydrogen bond nearby networks together, favoring interpenetration. Controlling the interplay between these intermolecular forces enables the reversal of omnipresent energetic equilibria, leading to thermodynamically favored open pore structures. The discovery of charged point-point repulsion will likely lead to the re-evaluation of non-interpenetrated network design, synthesis, and wide-reaching applications.