Theoretical Prediction and Experimental Evaluation of Topological Landscape and Thermodynamic Stability of a Fluorinated Zeolitic Imidazolate Framework

The
prediction of topological preferences and polymorph stability
remains a challenge for the design of metal–organic frameworks
exhibiting a rich topological landscape, such as zeolitic imidazolate
frameworks (ZIFs). Here, we have used mechanochemical screening and
calorimetry to test the ability of dispersion-corrected periodic density
functional theory (DFT) to accurately survey the topological landscape,
as well as quantitatively evaluate polymorph stability, for a previously
not synthesized ZIF composition. Theoretical calculations were used
to obtain an energy ranking and evaluate energy differences for a
set of hypothetical, topologically distinct structures of a fluorine-substituted
ZIF. Calculations were then experimentally validated via mechanochemical
screening and calorimetry, which confirmed two out of three theoretically
anticipated topologies, including a fluorinated analogue of the popular
ZIF-8, while revealing an excellent match between the measured and
theoretically calculated energetic differences between them. The results,
which speak strongly in favor of the ability of dispersion-corrected
periodic DFT to predict the topological landscape of new ZIFs, also
reveal the ability to use peripheral substituents on the organic linker
to modify the framework thermodynamic stability.