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Origin of Stacked-Ring Aromaticity

2009; American Chemical Society; Volume: 113; Issue: 27 Linguagem: Inglês

10.1021/jp900258a

1520-5215

Jun‐ichi Aihara,

Graphene research and applications

Although strong diatropic currents run in the pi-stacked dimers of 4n pi annulenes, they are still antiaromatic with negative topological resonance energies (TREs). The TRE difference between two annulene molecules and the pi-stacked annulene dimer can be used as a practical measure of stacked-ring aromaticity. As predicted by Corminboeuf et al., all pi-stacked 4n pi annulene dimers exhibit marked stacked-ring aromaticity. In contrast, the TRE for the entire conjugated system of a pi-stacked benzene dimer is much smaller than twice the TRE for benzene. The analysis of circuit contributions to energetic and magnetic properties shows that such stacked-ring aromaticity and diatropicity arise from many (4n + 2)-site circuits created by the stacking of two antiaromatic rings. Tetragonal faces formed in the dimers are responsible for the creation of these (4n + 2)-site circuits.