Chlorination of IPR C_(100) Fullerene Affords Unconventional C_(96)Cl_(20) with a Nonclassical Cage Containing Three Heptagons

摘要

Chlorination of C_(100) fullerene with a mixture of VCl4 and SbCl5 afforded C_(96)Cl_(20) with a strongly unconventional structure. In contrast to the classical fullerenes containing only hexagonal and pentagonal rings, the C_(96) cage contains three heptagonal rings and, therefore, should be classified as a fullerene with a nonclassical cage (NCC). There are several types of pentagon fusions in the C_(96) cage including pentagon pairs and pentagon triples. The three-step pathway from isolated-pentagon-rule (IPR) C_(100) to C_(96)(NCC-3hp) includes two C2 losses, which create two cage heptagons, and one Stone-Wales rotation under formation of the third heptagon. Structural reconstruction established C_(100) isomer no. 18 from 450 topo-logically possible IPR isomers as the starting C_(100) fullerene. Until now, no pristine C_(100) isomers have been confirmed based on the experimental results.