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.
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.
Cozzi
Franco
F
Dipartimento di Chimica Organica e Industriale, Università degli Studi di Milano via Venezian 21, 20133 Milano, Italy.
Bacchi
Sergio
S
Filippini
Giuseppe
G
Pilati
Tullio
T
Gavezzotti
Angelo
A
D000873:Anthracenes / Q000737:chemistry; D008956:Models, Chemical; D008968:Molecular Conformation; D009281:Naphthalenes / Q000737:chemistry; D010616:Phenanthrenes / Q000737:chemistry; D011084:Polycyclic Aromatic Hydrocarbons / Q000138:chemical synthesis* / Q000737:chemistry; D014961:X-Ray Diffraction / Q000379:methods
D000873:Anthracenes; D009281:Naphthalenes; D010616:Phenanthrenes; D011084:Polycyclic Aromatic Hydrocarbons