title: Molecular shape sorting using molecular organic cages.
abstract: The energy-efficient separation of chemical feedstocks is a major sustainability challenge. Porous extended frameworks such as zeolites or metal-organic frameworks are one potential solution to this problem. Here, we show that organic molecules, rather than frameworks, can separate other organic molecules by size and shape. A molecular organic cage is shown to separate a common aromatic feedstock (mesitylene) from its structural isomer (4-ethyltoluene) with an unprecedented perfect specificity for the latter. This specificity stems from the structure of the intrinsically porous cage molecule, which is itself synthesized from a derivative of mesitylene. In other words, crystalline organic molecules are used to separate other organic molecules. The specificity is defined by the cage structure alone, so this solid-state 'shape sorting' is, uniquely, mirrored for cage molecules in solution. The behaviour can be understood from a combination of atomistic simulations for individual cage molecules and solid-state molecular dynamics simulations.
authors.affiliation: Department of Chemistry and Centre for Materials Discovery, University of Liverpool, Brownlow Hill, Liverpool, Merseyside L69 3BX, UK.
authors.forename: Tamoghna
authors.initials: T
authors.lastname: Mitra
authors.forename: Kim E
authors.initials: KE
authors.lastname: Jelfs
authors.forename: Marc
authors.initials: M
authors.lastname: Schmidtmann
authors.forename: Adham
authors.initials: A
authors.lastname: Ahmed
authors.forename: Samantha Y
authors.initials: SY
authors.lastname: Chong
authors.forename: Dave J
authors.initials: DJ
authors.lastname: Adams
authors.forename: Andrew I
authors.initials: AI
authors.lastname: Cooper