Disclosure of the Elusive C2v-C72 Carbon Cage

摘要

The stability of all fullerenes (closed carbon cages composed of pentagons and hexagons) can be explained by a simple empirical rule that forbids direct pentagon pentagon junctions (the isolated pentagon rule). Among thousands of possible fullerene structures, only one was predicted to violate this rule, namely, C_2v-symmetric #11188C₇₂. In this work, we present the synthesis and isolation of this elusive fullerene cage for the first time. The C_2v-C₇₂ cage was captured by in situ chlorination to form C₇₂Cl₄, whose structure was unambiguously determined by single-crystal X-ray analysis. The chlorination pattern and resulting stability of C₇₂Cl₄ are discussed.