title: Trapping virtual pores by crystal retro-engineering.
abstract: Stable guest-free porous molecular crystals are uncommon. By contrast, organic molecular crystals with guest-occupied cavities are frequently observed, but these cavities tend to be unstable and collapse on removal of the guests-this feature has been referred to as 'virtual porosity'. Here, we show how we have trapped the virtual porosity in an unstable low-density organic molecular crystal by introducing a second molecule that matches the size and shape of the unstable voids. We call this strategy 'retro-engineering' because it parallels organic retrosynthetic analysis, and it allows the metastable two-dimensional hexagonal pore structure in an organic solvate to be trapped in a binary cocrystal. Unlike the crystal with virtual porosity, the cocrystal material remains single crystalline and porous after removal of guests by heating.
authors.affiliation: Department of Chemistry and Centre for Materials Discovery, University of Liverpool, L69 3BX, UK.
authors.forename: Marc A
authors.initials: MA
authors.lastname: Little
authors.affiliation: Department of Chemistry and Centre for Materials Discovery, University of Liverpool, L69 3BX, UK.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Briggs
authors.affiliation: Department of Chemistry and Centre for Materials Discovery, University of Liverpool, L69 3BX, UK.
authors.forename: James T A
authors.initials: JT
authors.lastname: Jones
authors.affiliation: Department of Chemistry and Centre for Materials Discovery, University of Liverpool, L69 3BX, UK.
authors.forename: Marc
authors.initials: M
authors.lastname: Schmidtmann
authors.affiliation: Department of Chemistry and Centre for Materials Discovery, University of Liverpool, L69 3BX, UK.
authors.forename: Tom
authors.initials: T
authors.lastname: Hasell
authors.affiliation: Department of Chemistry and Centre for Materials Discovery, University of Liverpool, L69 3BX, UK.
authors.forename: Samantha Y
authors.initials: SY
authors.lastname: Chong
authors.affiliation: Department of Chemistry, Imperial College London, SW7 2AZ, UK.
authors.forename: Kim E
authors.initials: KE
authors.lastname: Jelfs
authors.affiliation: Department of Chemistry and Centre for Materials Discovery, University of Liverpool, L69 3BX, UK.
authors.forename: Linjiang
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Chemistry and Centre for Materials Discovery, University of Liverpool, L69 3BX, UK.
authors.forename: Andrew I
authors.initials: AI
authors.lastname: Cooper