Synthesis, X‐ray Diffraction and Computational Study of the Crystal Packing of Polycyclic Hydrocarbons Featuring Aromatic and Perfluoroaromatic Rings Condensed in the Same Molecule: 1,2,3,4‐Tetrafluoronaphthalene, ‐anthracene and ‐phenanthrene

Abstract

We have synthesised some planar polycyclic compounds, in which unsubstituted aromatic rings are condensed with perfluorinated aromatic rings, and have carried out a combined X-ray diffraction and computational study to analyse their self-recognition behaviour in crystalline phases. We compare our results with the parent hydrocarbons and with other compounds that have a variable degree of fluorination. Whereas the molecular planes in crystals of hydrocarbons with mono- or difluorinated aromatic rings or of perfluorinated compounds arrange themselves in V-shaped configurations, our present results show that perfluorinated rings tend to stack over unsubstituted rings even when these two moieties coexist in a condensed system, producing crystalline materials with parallel molecular layers with the arene-perfluoroarene recognition pattern. Our analysis shows that the packing energy of all these crystals is dispersion-dominated and that coulombic terms are selective rather than quantitatively predominant in crystals with arene-perfluoroarene interactions. No compelling proof of a special role of C-H...F interactions has been found.

Elucidation of Structure and Dynamics in Solid Octafluoronaphthalene from Combined NMR, Diffraction, And Molecular Dynamics Studies

“…38 • rotation around the molecular C 2 axis. Our results essentially agree with those of Gavezzotti et al 33 although the better crystal quality allowed all atoms to be refined in anisotropic approximation and gave a much improved R-factor (3.1% vs 11.6%). The relative occupancies of the two orientations were refined, converging at 54.2(7) and 45.8(7)%.…”

Halogen⋯halogen contacts for the stabilization of a new polymorph of 9,10-dichloroanthracene

“…5). This supramolecular organization was also found in others three-fused rings related compounds [43]. In this interaction the molecules are related by translational symmetry along the crystallographic a axis and the anthracene rings are parallel with the corresponding centroids accordingly displaced.…”

Understanding of Noncovalent Interactions Involving Organic Fluorine

“…It was proposed that one of the hypothetical (computed) high pressure forms of benzene adopts the same tetragonal packing as fluorobenzene and hence C-H···F-C interactions behave similar to C-H···H interactions and have the same structure-directing ability. This conclusion was further supported in the crystal packing analysis of 1,2,3,4-tetrafluoronaphthalene, -anthracene, and -phenanthrene by Gavezzotti et al [69]. It was observed that the C-H···F-C interactions does not provide any significant stabilization to the crystal packing.…”