A study of the aromaticity of the heterofullerene C_(30)X6 and C_(24)X_(12) (X = B, N) analogs

摘要

The aromaticity of the heterofullerene isomers C_(30)X6 and C_(24)X_(12) (X = B, N), formed from the initial C_(36) fullerene with D_(6h) symmetry, has been investigated using both the topological resonance energy (TRE) and the percentage topological resonance energy (%TRE) methods. Our results obtained by the TRE and %TRE methods were compared with the nucleus-independent chemical shift (NICS) values at the cage center. The local aromaticity was studied using the bond resonance energy (BRE) method and compared with the NICS values of the individual rings. The local aromaticity orderings of the different hexagons were obtained using the BRE method. According to the BRE results, we can predict that the C-C bonds shared by two pentagons are stabilized by the introduction of nitrogen atoms, whereas the C-C bonds shared by two hexagons are destabilized by the introduction of boron atoms. The relative orders of the global and local aromaticity are highly dependent upon the types and numbers of the heteroatoms in the structure.