LAUSR

Nonclassical fullerene is a new member of the fullerene family. In the present work, a systematic investigation on LaxSc3-xN@C80 (x = 0-3) covering both classical and nonclassical C80 cages was performed utilizing density functional theory combined with statistical mechanics. At absolute zero, LaSc2N@Hept(6)-Cs(2)-C80 with a heptagon-containing nonclassical carbon is the second most stable isomer, whereas at the temperature range of endohedral metallofullerene (EMF) formation, due to the large vibrational frequencies, LaSc2N@Hept(6)-Cs(2)-C80 is the third most abundant isomer, and its mole fraction is very low, accounting for the low experimental yield of LaSc2N@Hept(6)-Cs(2)-C80; La2ScN@Hept(6)-Cs(2)-C80, and La3N@Hept(6)-Cs(2)-C80 are the overwhelming isomers of the corresponding series, but compared with the cases of Sc3N@C80 and LaSc2N@C80, La2ScN and La3N clusters suffer much larger constraints from the C80 cages, perhaps preventing the synthesis of La2ScN@C80 and La3N@C80 species. Because of the large mole fractions and large electron donation and back-donation of La2ScN@Hept(6)-Cs(2)-C80 and La3N@Hept(6)-Cs(2)-C80, it can be inferred that La2ScN and La3N clusters may be used to stabilize some other larger nonclassical fullerene cages. This work will provide useful insights into the origins of stabilization of nonclassical fullerene cages by endohedral derivation and guidelines for synthesis EMF with nonclassical cages.