Fused-Pentagon CCl and CCl Obtained via Chlorination-Promoted Skeletal Transformation of IPR C.

The isolated-pentagon-rule (IPR) -C fullerene is least susceptible to skeletal transformations in comparison with higher fullerenes and even C. A cage transformation in IPR C via a one-step Stone-Wales rearrangement was accomplished by high-temperature (440 °C) ampule chlorination with SbCl. Subsequent dechlorination at 450 °C, followed by high-performance liquid chromatography separation, allowed the isolation of non-IPR CCl and CCl. X-ray diffraction study revealed the presence of an unprecedented C carbon cage, possessing two pairs of fused pentagons and the chlorination patterns located on one cage hemisphere. A high energetic and thermal stability of both non-IPR chlorides was also confirmed by theoretical calculations of formation energies. Pathways of skeletal transformations of IPR C in comparison with those in C are discussed.