title: Absorbate-induced piezochromism in a porous molecular crystal.
abstract: Atmospherically stable porous frameworks and materials are interesting for heterogeneous solid-gas applications. One motivation is the direct and selective uptake of pollutant/hazardous gases, where the material produces a measurable response in the presence of the analyte. In this report, we present a combined experimental and theoretical rationalization for the piezochromic response of a robust and porous molecular crystal built from an extensively fluorinated trispyrazole. The electronic response of the material is directly determined by analyte uptake, which provokes a subtle lattice contraction and an observable bathochromic shift in the optical absorption onset. Selectivity for fluorinated absorbates is demonstrated, and toluene is also found to crystallize within the pore. Furthermore, we demonstrate the application of electronic structure calculations to predict a physicochemical response, providing the foundations for the design of electronically tunable porous solids with the chemical properties required for development of novel gas-uptake media.
authors.affiliation: Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, United Kingdom.
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Hendon
authors.forename: Kate E
authors.initials: KE
authors.lastname: Wittering
authors.forename: Teng-Hao
authors.initials: TH
authors.lastname: Chen
authors.forename: Watchareeya
authors.initials: W
authors.lastname: Kaveevivitchai
authors.forename: Ilya
authors.initials: I
authors.lastname: Popov
authors.forename: Keith T
authors.initials: KT
authors.lastname: Butler
authors.forename: Chick C
authors.initials: CC
authors.lastname: Wilson
authors.forename: Dyanne L
authors.initials: DL
authors.lastname: Cruickshank
authors.forename: Ognjen Š
authors.initials: OŠ
authors.lastname: Miljanić
authors.forename: Aron
authors.initials: A
authors.lastname: Walsh
keywords: Piezochromism; bathochromism; density functional theory; molecular crystal