Breathing-Assisted Selective Adsorption of C8 Alkyl Aromatics in Zn-Based Metal-Organic Frameworks |
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Authors: | Jihyun Lee Dr Younghoon Kim Younghu Son Dr Hyehyun Kim Dr Yong Nam Choi Prof?Dr Deanna D'Alessandro Dr Purna Chandra Rao Prof?Dr Minyoung Yoon |
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Institution: | 1. Department of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, Daegu, 41566 Republic of Korea;2. Center for Self-assembly and Complexity, Institute for Basic Science, Department of Chemistry, POSTECH, Pohang, 37673 Republic of Korea
These authors contributed equally to this work.;3. Neutron Science Division, Korea Atomic Energy Research Institute, Daejeon, 34057 Republic of Korea;4. Nuclear Hydrogen Research Team, Korea Atomic Energy Research Institute, Daejeon, 34057 Republic of Korea;5. School of Chemistry, The University of Sydney, Sydney, 2006 New South Wales, Australia |
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Abstract: | The breathing phenomenon in metal-organic frameworks (MOFs) has revealed supramolecular host-guest interactions that could be beneficial for chemical separation in numerous industrial applications. The cost-effective purification of C8 alkyl aromatics such as o-xylene, m-xylene, p-xylene, and ethylbenzene remains challenging owing to their similar molecular structures, boiling points, kinetic diameters, polarities, etc. Herein, we report two Zn-based pillar-bilayered MOFs, denoted Zn2(aip)2(pillar)] (aip=5-aminoisophthalic acid; pillar: bpy=4,4’-bipyridine or bpe=1,2-bis(4-pyridyl)ethane) that exhibit a breathing effect depending on the adsorbed guest molecules. Guest-dependent sorption studies in organic solvents such as N,N-dimethylformamide, methanol, benzene, and water vapor display reversible structural flexibility through the breathing effect in both framework compounds. The experiments conducted on C8-alkyl aromatics resulting in both MOF compounds can access these isomers in the shrunken pores, and thereby expand the pore size by framework breathing. In C8 binary mixtures, these Zn-MOFs exhibit selective sorption properties based on the different interactions between guest C8 aromatics and the framework structure. |
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Keywords: | adsorption breathing effect flexibility isomer separation metal-organic frameworks |
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