Regiospecific coordination of Re(3) clusters with the sumanene-type hexagons on endohedral metallofullerenes and higher fullerenes that provides an efficient separation method.

The reactions of [(μ-H)3 Re3 (CO)11 (NCMe)] with Sc2 @C82 -C3v (8), Sc2 C2 @C80 -C2v (5), Sc2 O@C82 -Cs (6), C86 -C2 (17), and C86 -Cs (16) have been carried out to produce face-capping cluster complexes. The Re3 triangles are found to bind to the sumanene-type hexagons on the fullerene surface regiospecifically. In contrast, Sc3 N@C78 -D3h (5) and Sc3 N@C80 -Ih show no reactivity toward [(μ-H)3 Re3 (CO)11 (NCMe)], probably due to electronic and steric factors. These complexes can be easily purified by using HPLC. Carbonylation of each complex releases the corresponding higher fullerene or endohedral metallofullerene in pure form. Remarkably, the C86 -C2 (17) and C86 -Cs (16) isomers were successively separated through Re3 cluster complexation/decomplexation. This unique bonding feature may provide an attractive general strategy to purify as yet unresolved fullerene mixtures.