Understanding gas capacity, guest selectivity, and diffusion in porous liquids.
Understanding gas capacity, guest selectivity, and diffusion in porous liquids.
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DOI：
10.1039/c6sc05196k
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发表时间：
2017-04-01
期刊：
影响因子：
8.4
通讯作者：
Cooper AI
中科院分区：
文献类型：
--
作者：
Greenaway RL;Holden D;Eden EGB;Stephenson A;Yong CW;Bennison MJ;Hasell T;Briggs ME;James SL;Cooper AI
利用测量技术、分子模拟和对照实验对多孔液体进行深入研究，以促进对其定量的理解。多孔液体是一种新型材料，可用于气体分离和均相催化等领域。在这里，我们使用测量技术、分子模拟和对照实验相结合的方法来促进对这些液体的定量理解。特别是，我们发现在没有合适的客体的情况下，笼腔中的空腔仍然没有被占据，并且液体可以吸附大量的气体，对于Xe和SF6，笼子中的气体占有率分别高达72%和74%。气体可以通过使用非化学触发器(如超声波)进行可逆加载和释放，这意味着气体分离方案的可能性。扩散核磁共振实验表明，气体在笼腔内处于结合状态和非结合状态之间的动态平衡，这与最近对相关多孔液体的模拟一致。与多孔有机笼状固体中气体吸附的比较表明，多孔液体具有相似的气体结合亲和力，并且笼状分子的物理性质被转化为液态。相比之下，一些物理性质是不同的：例如，固体同手性多孔笼对手性芳香醇表现出对映体选择性，而同等的同手性多孔液则没有。这可以归因于各向同性多孔液体中超分子组织的损失。
An in-depth study of porous liquids using measurement techniques, molecular simulations, and control experiments to advance their quantitative understanding. Porous liquids are a new class of material that could have applications in areas such as gas separation and homogeneous catalysis. Here we use a combination of measurement techniques, molecular simulations, and control experiments to advance the quantitative understanding of these liquids. In particular, we show that the cage cavities remain unoccupied in the absence of a suitable guest, and that the liquids can adsorb large quantities of gas, with gas occupancy in the cages as high as 72% and 74% for Xe and SF6, respectively. Gases can be reversibly loaded and released by using non-chemical triggers such as sonication, suggesting potential for gas separation schemes. Diffusion NMR experiments show that gases are in dynamic equilibrium between a bound and unbound state in the cage cavities, in agreement with recent simulations for related porous liquids. Comparison with gas adsorption in porous organic cage solids suggests that porous liquids have similar gas binding affinities, and that the physical properties of the cage molecule are translated into the liquid state. By contrast, some physical properties are different: for example, solid homochiral porous cages show enantioselectivity for chiral aromatic alcohols, whereas the equivalent homochiral porous liquids do not. This can be attributed to a loss of supramolecular organisation in the isotropic porous liquid.