Synthesis and Structures of Fullerene Bromides and Chlorides

Halogenated fullerenes have been subjects of intensive investigations since the discovery of fullerene, because of their possible further derivatization. This paper reviews the synthesis and molecular structures of fullerene bromides and chlorides, covering earlier work in this field and progress in synthetic methods developed by the authors. The use of inorganic chlorides and oxychlorides for the chlorination of fullerenes allowed the preparation of new compounds that have been fully characterized by single‐crystal X‐ray diffraction and IR spectroscopy and confirmed by theoretical calculations. Comparison between fullerene bromides, chlorides, and fluorides has revealed that the maximum degrees of halogenation and compound stability increase from the bromides to the fluorides. The larger Cl and Br atoms and the lower C–Hal energies also engender significant differences in addition patterns of the C60Haln and C70Halm molecules in relation to those of the fluorides. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)