Cl. Lin et al., BOND ALTERNATION AND ENERGY INCREMENT IN LINEAR AND ANGULAR ISOMERS OF [N]PHENYLENES, Journal of the Chinese Chemical Society, 45(1), 1998, pp. 13-16
From recent accurate ab initio calculation on [N]phenylenes by Schulma
n and Disch, some regular patterns for bond alternation and energy inc
rement can be found. We interpreted these results by considering a ''u
nit cell'' of interior benzene rings fused to two four-membered rings
in either linear or angular fashion. Our model works better in account
ing for the structure than for the energy.