A Rational Chemical Synthesis of C 60

Isolable quantities of C60, 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 C60 when subjected to flash vacuum pyrolysis at 1100 degrees 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 C60, should make possible the directed laboratory preparation of other fullerenes as well, including those not accessible by graphite vaporization.