Date Published: June 01, 2011
Publisher: International Union of Crystallography
Author(s): Sebastian Förster, Frank Eissmann, Wilhelm Seichter, Edwin Weber.
There are two molecules in the asymmetric unit of the title compound, C14H6F6O2, in which the azulene systems possess an almost planar geometry with maximum deviations of 0.0438 (15) and 0.0396 (14) Å. Besides intra- and intermolecular C—H⋯O and C—H⋯F interactions, the structure displays three F⋯F contacts [2.793 (2), 2.8820 (17) and 2.9181 (16) Å]. Furthermore, a characteristic azulene π-stacking is observed with an alternating sequence of electron-rich five-membered rings and electron-deficient seven-membered rings [centroid–centroid distances = 3.5413 (12), 3.6847 (12), 3.5790 (12) and 3.7718 (12) Å].
For the synthesis, see: Mathias & Overberger (1980 ▶); Zielinski et al. (2008 ▶). For the crystal structure of the parent azulene, see: Robertson et al. (1962 ▶). For halogen interactions in molecular crystal structures, see: Brammer et al. (2001 ▶); Metrangolo et al. (2008 ▶).