A Rational Chemical Synthesis of [C.sub.60]. (Reports)

Isolable quantities of [C.sub.60], the smallest stable fullerene, have been synthesized in 12 steps from commercially available starting materials by rational chemical methods. A molecular polycyclic aromatic precursor bearing chlorine substituents at key positions forms [C.sub.60] when subjected to flash vacuum pyrolysis at 1100 ° C. No other fullerenes are formed as by-products. The methods we have developed for the target-specific synthesis of fullerenes, applied here to a synthesis of [C.sub.60], should make possible the directed laboratory preparation of other fullerenes as well, including those not accessible by graphite vaporization.
Although [C.sub.60] and some of the higher fullerenes can be readily prepared by resistive heating of graphite (1), there is still considerable interest in the rational stepwise synthesis of these [...]