Dissecting the packing forces in mixed perfluorocarbon/aromatic co-crystals

Abstract

We carried out a systematic evaluation of the packing forces in co-crystals featuring monoiodo- and diiodo-perfluoroalkanes and 1,2,4-oxadiazoles through single crystal X-ray diffraction and theoretical analysis. The molecules assemble via a combination of halogen bonding and specific dispersive interactions involving the perfluorinated units. We quantitatively elucidated the nature and strength of such interactions through solid-state calculations and Hirshfeld surface analysis. One of the co-crystals, formed by two monoiodoperfluorodecane molecules, the longest perfluorinated chain ever solved at the atomic level, allowed us to fully highlight the role of fluorous interactions.