Giant benzenoid hydrocarbons. Superphenalene resonance energy

We have calculated the molecular resonance energy for "superphenalene," a recently reported giant benzenoid that can be viewed as obtained from three fused "superbenzenes" (hexa-peri-hexabenzocoronenes). Using the method of conjugated circuits we derived quantitative characterization of Clar's qualitative description of the considered benzenoids as composed from disjoint "pi-sextets." The calculations show the degree of differentiation between neighboring rings, which decreases as we progressively move towards the center of the molecule.