Molecular Mechanism of Swing Effect in Zeolitic Imidazolate Framework ZIF-8: Continuous Deformation upon Adsorption

François-Xavier Coudert (1)

1 IRCP - Institut de Recherche de Chimie Paris

Zeolitic Imidazolate Framework ZIF-8 displays flexibility of its framework by rotation of its imidazolate linker. This "swing effect" has been widely described in the literature, both experimental and theoretical, as a bistable system where the linker oscillates between two structures: "open window" and "closed window". By using quantum chemistry calculations and first principles molecular dynamics simulations, it is shown that the deformation upon adsorption is in fact continuous upon pore loading, with thermodynamics of packing effects the reason behind stepped adsorption isotherms experimentally observed. Finally, we study a variant of ZIF-8 with a different linker, highlighting the influence of the linker and the balance of microscopic interactions on the framework's flexibility.

Domaines: Chimie; Chimie théorique et/ou physique; Matériaux

François-Xavier Coudert. Molecular Mechanism of Swing Effect in Zeolitic Imidazolate Framework ZIF-8: Continuous Deformation upon Adsorption. ChemPhysChem, 2017, 18 (19), pp.2732-2738. ⟨10.1002/cphc.201700463⟩. ⟨hal-02265103⟩