On the Nature of Nonplanarity in the [N]Phenylenes

The unusual solid-state nonplanarity seen in the X-ray structures of the [N]phenylenes (an example is shown here) is shown to be most likely the result of crystal-packing-induced deformations. These conclusions are based on a study of published and eight new structure determinations, comparison with data on napththalenes and anthracenes obtained from the Cambridge Structural Database, and ab initio calculations.