Isolation and Crystallographic Characterization of Two, Nonisolated Pentagon Endohedral Fullerenes: Ho N@C (22010)-C and Tb N@C (22010)-C.

Purified samples of Ho N@C (22010)-C and Tb N@C (22010)-C have been isolated by two distinct processes from the rich array of fullerenes and endohedral fullerenes present in carbon soot from graphite rods doped with Ho O or Tb O . Crystallographic analysis of the endohedral fullerenes as cocrystals with Ni(OEP) (in which OEP is the dianion of octaethylporphyrin) shows that both molecules contain the chiral C (22010)-C cage. This cage does not obey the isolated pentagon rule (IPR) but has two sites where two pentagons share a common C-C bond. These pentalene units bind two of the metal ions, whereas the third metal resides near a hexagon of the cage. Inside the cages, the Ho N or Tb N unit is planar. Ho N@C (22010)-C and Tb N@C (22010)-C use the same cage previously found for Gd N@C (22010)-C rather than the IPR-obeying cage found in Sc N@D -C .