The long-debated origin of the narrow line-width signal in the EPR spectrum of C60- is shown to be C120O-, arising from unavoidable C120O impurity in air-exposed samples of C60.

A new superacid, H(CB11H6X6) (where X = chlorine or bromine), whose conjugate base is the exceptionally inert CB11H6X6- carborane anion, separates Bronsted acidity from oxidizing capacity and anion nucleophilicity in a manner not previously achieved. Reaction of this superacid with C60 gives HC60+ as a stable ion in solution and in the solid state. In a separate experiment, an oxidant was developed such that the long-sought C60.+ ion can be synthesized in solution. The preparation of these two fullerene carbocations is a notable departure from the prevalent chemistry of C60, which is dominated by the formation of anions or the addition of nucleophiles. The H(CB11H6X6) superacid overcomes the major limitations of presently known superacids and has potentially wide application.

Naturally assembling cocrystallates of C60 and C70 fullerenes with tetraphenylporphyrins (H2TPP · C60 · 3 toluene, 1; H2T(3,5-dibutyl)PP · C60, 2; H2T(3,5-dimethyl)PP · 1.5C60 · 2 toluene, 3; H2T(piv)PP · C60, 4; H2T(3,5-dimethyl)PP · C70 · 4 toluene, 5; ZnTPP · C70, 6; NiT(4-methyl)PP · 2C70 · 2 toluene, 7) show unusually short porphyrin/fullerene contacts (2.7-3.0 Å) compared with typical π-π interactions (3.0-3.5 Å). In the C60 structures, an electron-rich, 6:6 ring juncture, C-C bond lies over the center of the porphyrin ring. In the C70 structures, the ellipsoidal fullerene makes porphyrin contact at its equator rather than its poles; a carbon atom from three fused six-membered rings lies closest to the center of the porphyrin. These structures provide an explanation for the manner in which tetraphenylporphyrin-appended silica stationary phases effect the chromatographic separation of fullerenes. The interaction of the curved π surface of a fullerene with the planar π surface of a porphyrin, without the need for matching convex with concave surfaces, represents a new recognition element in supramolecular chemistry. NMR measurements show that this interaction persists in toluene solution, suggesting a simple way to assemble van der Waals complexes of donor-acceptor chromophores.