Octaphenylbiphenylene and Dodecaphenyltriptycene

Octaphenylbiphenylene, the expected dimer of tetraphenylbenzyne, has been prepared in low
yield by diazotization of 3,4,5,6-tetraphenylanthranilic acid, and its X-ray structure has been determined.
The X-ray structure of a second, abnormal dimer of tetraphenylbenzyne, 1,2,3,8,9,10-hexaphenyldibenzo[fg,op]naphthacene has also been determined; this is a saddle-shaped polycyclic aromatic hydrocarbon.
1,2,3,4,5,6,7,8,13,14,15,16-Dodecaphenyltriptycene, perhaps the most crowded triptycene derivative yet
prepared, has been made by the reaction of tetraphenylbenzyne with 1,2,3,4,5,6,7,8-octaphenylanthracene,
which in turn was synthesized in two steps from commercial starting materials. The X-ray structure of the
dodecaphenyltriptycene nonabenzene solvate is a remarkable channel containing structure in which more
than 50% of the unit cell volume is occupied by the benzene molecules.