Highly Stable [C₆₀AuC₆₀]^+/– Dumbbells

Ionic complexes between gold and C60 have been observed for the first time. Cations and anions of the type [Au­(C60)2]+/– are shown to have particular stability. Calculations suggest that these ions adopt a C60–Au–C60 sandwich-like (dumbbell) structure, which is reminiscent of [XAuX]+/– ions previously observed for much smaller ligands. The [Au­(C60)2]+/– ions can be regarded as Au­(I) complexes, regardless of whether the net charge is positive or negative, but in both cases, the charge transfer between the Au and C60 is incomplete, most likely because of a covalent contribution to the Au–C60 binding. The C60–Au–C60 dumbbell structure represents a new architecture in fullerene chemistry that might be replicable in synthetic nanostructures.