title: Separation of rare gases and chiral molecules by selective binding in porous organic cages.
abstract: The separation of molecules with similar size and shape is an important technological challenge. For example, rare gases can pose either an economic opportunity or an environmental hazard and there is a need to separate these spherical molecules selectively at low concentrations in air. Likewise, chiral molecules are important building blocks for pharmaceuticals, but chiral enantiomers, by definition, have identical size and shape, and their separation can be challenging. Here we show that a porous organic cage molecule has unprecedented performance in the solid state for the separation of rare gases, such as krypton and xenon. The selectivity arises from a precise size match between the rare gas and the organic cage cavity, as predicted by molecular simulations. Breakthrough experiments demonstrate real practical potential for the separation of krypton, xenon and radon from air at concentrations of only a few parts per million. We also demonstrate selective binding of chiral organic molecules such as 1-phenylethanol, suggesting applications in enantioselective separation.
authors.affiliation: Department of Chemistry and Centre for Materials Discovery, University of Liverpool, Crown Street, Liverpool L69 7ZD, UK.
authors.forename: Linjiang
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Chemistry and Centre for Materials Discovery, University of Liverpool, Crown Street, Liverpool L69 7ZD, UK.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Reiss
authors.affiliation: Department of Chemistry and Centre for Materials Discovery, University of Liverpool, Crown Street, Liverpool L69 7ZD, UK.
authors.forename: Samantha Y
authors.initials: SY
authors.lastname: Chong
authors.affiliation: Department of Chemistry and Centre for Materials Discovery, University of Liverpool, Crown Street, Liverpool L69 7ZD, UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Holden
authors.affiliation: Department of Chemistry and Centre for Materials Discovery, University of Liverpool, Crown Street, Liverpool L69 7ZD, UK.
authors.forename: Kim E
authors.initials: KE
authors.lastname: Jelfs
authors.affiliation: Department of Chemistry and Centre for Materials Discovery, University of Liverpool, Crown Street, Liverpool L69 7ZD, UK.
authors.forename: Tom
authors.initials: T
authors.lastname: Hasell
authors.affiliation: Department of Chemistry and Centre for Materials Discovery, University of Liverpool, Crown Street, Liverpool L69 7ZD, UK.
authors.forename: Marc A
authors.initials: MA
authors.lastname: Little
authors.affiliation: Department of Chemistry and Centre for Materials Discovery, University of Liverpool, Crown Street, Liverpool L69 7ZD, UK.
authors.forename: Adam
authors.initials: A
authors.lastname: Kewley
authors.affiliation: Department of Chemistry and Centre for Materials Discovery, University of Liverpool, Crown Street, Liverpool L69 7ZD, UK.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Briggs
authors.affiliation: Department of Chemistry and Centre for Materials Discovery, University of Liverpool, Crown Street, Liverpool L69 7ZD, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Stephenson
authors.affiliation: Wolfson Northern Carbon Reduction Laboratories, Drummond Building, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.
authors.forename: K Mark
authors.initials: KM
authors.lastname: Thomas
authors.affiliation: Wolfson Northern Carbon Reduction Laboratories, Drummond Building, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.
authors.forename: Jayne A
authors.initials: JA
authors.lastname: Armstrong
authors.affiliation: Wolfson Northern Carbon Reduction Laboratories, Drummond Building, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.
authors.forename: Jon
authors.initials: J
authors.lastname: Bell
authors.affiliation: CPPM, Aix-Marseille Université, CNRS/IN2P3, 163 avenue de Luminy, case 902, 13009 Marseille, France.
authors.forename: Jose
authors.initials: J
authors.lastname: Busto
authors.affiliation: CPPM, Aix-Marseille Université, CNRS/IN2P3, 163 avenue de Luminy, case 902, 13009 Marseille, France.
authors.forename: Raymond
authors.initials: R
authors.lastname: Noel
authors.affiliation: Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.affiliation: Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: Denis M
authors.initials: DM
authors.lastname: Strachan
authors.affiliation: Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: Praveen K
authors.initials: PK
authors.lastname: Thallapally
authors.affiliation: Department of Chemistry and Centre for Materials Discovery, University of Liverpool, Crown Street, Liverpool L69 7ZD, UK.
authors.forename: Andrew I
authors.initials: AI
authors.lastname: Cooper