Indium-containing heterofullerenes and their η5-π-complexes

The molecular and electronic structure of hypothetical metallofullerenes In5C55 (In) and In10C60 (2a) were simulated by the MNDO/PM3 method. Formally, heterofullerene 1a is obtained from the C-60 cluster by replacement of the carbon atoms at alpha-positions relative to one of the pentagons by In atoms, and cluster 2a is obtained from the C-70 cluster by replacement of the carbon atoms framing the polar pentagons of this fullerene by In atoms. Along with clusters 1a and 2a, their eta(5)-pi-complexes In(eta(5)-1a) (1b) and In-2(2 eta(5)-2a) (2b) with one (1b) and two (2b) exohedral In atoms coordinated to the pentagons (pent*) isolated by In atoms were also studied. The energies of the In-pent* bonds in 1b and 2b are approximately equal to 104 kcal mol(-1).