Aromaticity of All Possible C 26 N 2 Isomers

The aromaticity of all possible heterofullerenes C 26 N 2 and C 28 based on T d symmetry has been studied by means of the topological resonance energy and percentage topological resonance energy methods. The relationship between the aromaticity of the C 26 N 2 isomers and the sites where nitrogen atoms dope at the C 28 cage has been discussed. The calculation results show that the most stable isomer of C 26 N 2 derivatives is formed by nitrogen atoms doping at the two tetrahedral vertices. C 26 N 2 isomers are more stable than C 28 , but the C 26 N 2 2− isomers are less stable than C 28 4− 4. The effect of nitrogen substitution on C 28 stability was investigated by the topological charge stabilization rule.