The acenes: Is there a relationship between aromatic stabilization and reactivity?

[GRAPHICS] Despite the increasing reactivity from benzene to heptacene, the acene resonance energies per pi electron are nearly constant. The reactivities (computed activation energies) of the individual acene rings correlate with the reaction energies and depend on the product stabilities. Nucleus-independent chemical shifts (NICS; note the sizes of the red dots, above) indicate that the more reactive inner rings actually are more aromatic than the less reactive outer rings and even more aromatic than benzene itself.