| Abstract
| - The local aromaticity of the six-membered rings in three series of benzenoid compounds, namely,the [n]acenes, [n]phenacenes, and [n]helicenes for n = 1−9, has been assessed by means of threeprobes of local aromaticity based on structural, magnetic, and electron delocalization properties.For [n]acenes our analysis shows that the more reactive inner rings are more aromatic than theouter rings. For [n]phenacenes, all indicators of aromaticity show that the external rings are themost aromatic. From the external to the central ring, the local aromaticity varies in a dampedalternate way. The trends for the [n]helicene series are the same as those found for [n]phenacenes.Despite the departure from planarity in [n]helicenes, only a very slight loss of aromaticity is detectedin [n]helicenes as compared to the corresponding [n]phenacenes. Finally, because of magneticcouplings between superimposed six-membered rings in the higher members of the [n]helicenesseries, we have demonstrated that the NICS indicator of aromaticity artificially increases the localaromaticity of their most external rings.
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