Structures, stabilities, aromaticity, and electronic properties of C66 fullerene isomers, anions (C66 22, C66 42, C66 62), and metallofullerenes (Sc2@C66)

Abstract

Among all the 4478 classical isomers of C66, C66(Cs:0060) with the lowest number of pentagon–pentagon fusions was predicted to be the most stable isomer, followed by isomers C66(C2v:0011) and C66(C2:0083). The infrared spectra and aromaticity of the most stable isomers were predicted. The relative stabilities of C66 isomers change with charges or doping of metals. The structures and relative stabilities of the most stable metallofullerenes were delineated and compared with experiment. Sc2@C66(C2:0083) was predicted to be the most stable metallofullerene, although Sc2@C66(C2v:0011) was observed. Charge-transfer from Sc2 to the fused pentagons and the bonding between these two moieties significantly decrease the strain energies caused by the pair of fused pentagons thereby stabilizing the fullerene cage.