title: Gas-induced transformation and expansion of a non-porous organic solid.
abstract: Organic solids composed by weak van der Waals forces are attracting considerable attention owing to their potential applications in gas storage, separation and sensor applications. Herein we report a gas-induced transformation that remarkably converts the high-density guest-free form of a well-known organic host (p-tert-butylcalix[4]arene) to a low-density form and vice versa, a process that would be expected to involve surmounting a considerable energy barrier. This transformation occurs despite the fact that the high-density form is devoid of channels or pores. Gas molecules seem to diffuse through the non-porous solid into small lattice voids, and initiate the transition to the low-density kinetic form with approximately 10% expansion of the crystalline organic lattice, which corresponds to absorption of CO2 and N2O (refs 4,5). This suggests the possibility of a more general phenomenon that can be exploited to find more porous materials from non-porous organic and metal-organic frameworks that possess void space large enough to accommodate the gas molecules.
authors.affiliation: Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, Washington 99352, USA. Praveen.Thallapally@pnl.gov
authors.forename: Praveen K
authors.initials: PK
authors.lastname: Thallapally
authors.forename: B Peter
authors.initials: BP
authors.lastname: McGrail
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Dalgarno
authors.forename: Herbert T
authors.initials: HT
authors.lastname: Schaef
authors.forename: Jian
authors.initials: J
authors.lastname: Tian
authors.forename: Jerry L
authors.initials: JL
authors.lastname: Atwood