| Abstract
| - Heteroatom-substituted acepentalene derivatives which are isoelectronic with the known acepentalenediidedianion are nonplanar, fused aromatic tricycles which are hemifullerenes of the corresponding C20heteroanalogue. Depending on the number and position of heteroatoms, they may be anionic, neutral, orcationic. A nucleus-independent chemical shift study indicates that substitution of the central carbon ofthe acepentalenediide system with N or O results in a substantial increase in aromaticity. Peripheral azasubstitution on the other hand tends to increase curvature and decrease aromaticity. Alkylation orprotonation at the central position of asymmetrically substituted heteroacepentalenides leads to chiral,bowl-shaped, 10π aromatic species.
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