In order to investigate and probe the possible mechanism of rearrangement of trans-hexaphenyldifluorotricyclooctadiene, (a dimer of fluorotriphenylcyclobutadiene), to pentaphenyldihydrodifluoropentalene via C-F bond migration (Choudhury et al.,2007), a high temperature study of the title compound was performed at 400 (2) K. It was hoped that at that temperature C-F bond cleavage would occur to produce the rearrangement product pentaphenyldihydrodifluoropentalene. However, no additional migratory process was in fact observed.
The eight-membered cyclooctadiene ring exists in a sofa conformation, Fig 1. This also depicts the relative disposition of the phenyl and fluoro substituents around the eight-membered ring. The dihedral angles between the central four membered ring and the two fused four membered rings other rings on either side are 66.03 (2)° and 65.39 (2)° respectively. The crystal structure is stabilized by the formation of inversion related dimers linked by C-H•••π interactions (Fig. 2).
Experimental
The title compound was synthesized in accordance with the procedure reported in literature (Nagarajan et al., 1964). Crystals were obtained by recrystallization from chloroform and ethanol 2:1 (v:v).
Refinement
All the H atoms were fixed in calculated positions and allowed to ride on the parent carbon atoms with C-H = 0.93Å and U (eq) H = 1.2 U (eq) C.