Simulation of the molecular and electronic structure of heterofullerenes C55Y5 (Y=Si, Ge, Sn, B, Al, N, P, SiH, GeH, SnH) and their η-π-complexes with Li by the MNDO method

Qualitative estimates of the relative stability of hypothetical heterofullerenes C₅₅Y₅ (Y=Si, Ge, Sn, B, Al, N, P, SiH, GeH, SnH) and some η⁵-π-complexes LiC₅₅Y₅ were carried out by the MNDO method. Atoms Y (or groups XH) are assumed to substitute those C atoms in fullerene C₆₀ which are located at the -positions of a separated pentagonal face (pent^*) of this polyhedral molecule. It is shown that the spin densities in radicals C₅₅Y₅ (Y=SiH, GeH, SnH, B, Al, N, P) are localized on the separated pentagon atoms and the Li-pentagonal face (Li-pent^*) bonds in η⁵-π-complexes of these radicals with the Li atom are considerably stronger than Li-pent^* bonds in complexes η⁵-π-LiC₆₀]⁺ and η⁵-π-LiC₆₀] of unsubstituted C₆₀. In addition, it is established that the Li-pent^* bond energies in η⁵-π-complexes LiC₅₅B₅ and LiC₅₅Al₅ exceed the energy of the Li-pent^* bond in the η⁵-π-complex LiC₆₀H₅ studied earlier. In contrast, the energies of similar bonds for Y=N, P are close to the energy of the Li-pent^* bond in the η⁵-π-complex LiC₆₀H₅.