A nematic [60]fullerene supermolecule: when polyaddition leads to supramolecular self-organization at room temperature

The synthesis, liquid-crystalline properties and supramolecular organization of a [60]fullerene-based supermolecule are described, and the great potential of the spherical carbonated polyhedron to produce new materials through its multiple and addressable regioselective functionalization is emphasized. Indeed, hexaaddition on the carbon sphere has allowed the preparation, in 50% yield, of the first room-temperature enantiotropic nematic C₆₀-based material, even though the promoter was not mesomorphic. Despite the high molecular weight of such a supermolecule, the resulting material was revealed to be easily oriented in its mesophase by a magnetic field; this has allowed, by small angle X-ray diffraction investigations, a fine description of the molecular organization and of the corresponding relevant interactions involved. These results open the way to multifuntional materials that can take advantage of such an easy orientation of the grafted active chromophores (donor and acceptor) to be particularly efficient (for example in the design of photovoltaic materials).