Structures and stabilities of hydroazafullerenes C60−n(NH)n (n=2-3)

The structures and stabilities of C60−n(NH)n (n=2-3) isomers have been investigated by AM1 and B3LYP/6-31G* methods. The lowest energy structure of C58(NH)2 is 1,9/16,17-isomer, in which the second pair of N and H substitute and add, respectively, on a 6-6 bond located on the equator. The most stable isomer of C57(NH)3 contains a pyrrole moiety, the driving force governing the stabilities of C57(NH)3 isomers may be the formation of the local aromatic substructure. The calculations indicate that N and H atoms contiguously substitute and add, respectively, on the adjacent 6-6 double bond that is energetically unfavorable.