Selective synthesis of Co8S15 cluster in bowl-shaped template of the pentaaryl[60]fullerene ligand.

A cobalt-sulfur cluster Co8S15 with molecular formula of (C60Ar5)-Co8S15(n)Bu2-(C60Ar5) (Ar = 4-(t)BuC6H4) was selectively synthesized from a pentaaryl[60]fullerene cobalt trisulfide complex, (η(5)-C60Ar5)CoS3. The bowl-shaped steric templating fullerene ligand, as well as the metastable cobalt trisulfide moiety, played important roles in the exclusive cluster formation. X-ray crystallography, as well as electrochemical, time-resolved photophysical, and magnetic, measurements revealed a mixed-valence cluster with six cobalt(III) and two high-spin cobalt(II) centers showing reversible redox behavior and photoinduced charge separation.