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The ionic metallocene complexes [Cp*(2)M][BPh(4)] (Cp* = C(5)Me(5)) of the trivalent 3d metals Sc, Ti, and V were synthesized and structurally characterized. For M = Sc, the anion interacts weakly with the metal center through one of the phenyl groups, but for M = Ti and V, the cations are naked. They each contain one strongly distorted Cp* ligand, with one (V) or two (Ti) agostic C-H...M interactions involving the Cp*Me groups. For Sc and Ti, these Lewis acidic species react with fluorobenzene and 1,2-difluorobenzene to yield [Cp*(2)M(kappaF-FC(6)H(5))(n)][BPh(4)] (M = Sc, n = 2; M = Ti, n = 1) and [Cp*(2)M(kappa(2)F-1,2-F(2)C(6)H(4))][BPh(4)], the first examples of kappaF-fluorobenzene and kappa(2)F-1,2-difluorobenzene adducts of transition metals. With the perfluorinated anion [B(C(6)F(5))(4)](-), both Sc and Ti form [Cp*(2)M(kappa(2)F-C(6)F(5))B(C(6)F(5))(3)] contact ion pairs. The nature of the metal-fluoroarene interaction was studied by density functional theory (DFT) calculations and by comparison with the corresponding tetrahydrofuran (THF) adducts and was found to be predominantly electrostatic for all metals studied.

Deflated buckyballs: The single‐crystal structure of C60F48⋅2 (mesitylene) revealed the presence of both D3 and S6 isomers in the same crystal. C(sp2)−C(sp2) bonds (1.30 Å) are much shorter than C(sp3)−C(sp3) bonds (1.54–1.63 Å). The C60 cage is characterized by concave areas in the regions of six double bonds (see picture). Each double bond is effectively shielded by four F atoms, which accounts for the low reactivity of C60F48.

To elucidate the structures of C60F36 and C60F48, X-ray diffraction and electron diffraction experiments have been performed. It was found that the X-ray diffractograms of C60F36 and C60F48 at room temperature are indexed by bcc and bct lattices, respectively. In situ X-ray diffraction experiments at high temperatures have been also undertaken. The bct to fcc phase transition of C60F48 was observed. The mechanism of the transition and the stabilities of the structures of fluorinated fullerenes are discussed.