Two I h -symmetry-breaking C 60 isomers stabilized by chlorination

• Published in: Nature materials Vol. 7; no. 10; pp. 790 - 794
• Main Authors: Xie, Su-Yuan, Tan, Yuan-Zhi, Liao, Zhao-Jiang, Qian, Zhuo-Zhen, Chen, Rui-Ting, Wu, Xin, Liang, Hua, Han, Xiao, Zhu, Feng, Zhou, Sheng-Jun, Zheng, Zhiping, Lu, Xin, Huang, Rong-Bin, Zheng, Lan-Sun
• Format: Journal Article
• Language: English
• Published: 01.10.2008
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/nmat2275

One abiding surprise in fullerene science is that Ih-symmetric buckminsterfullerene C60 (ref. 1) (Ih-C60 or #1,812C60, the nomenclature specified by symmetry or by Fowler's spiral algorithm) remains the sole C60 species experimentally available. Setting it apart from the other 1,811 topological isomers (isobuckminsterfullerenes) is its exclusive conformity with the isolated-pentagon rule, which states that stable fullerenes have isolated pentagons. Although gas-phase existence of isobuckminsterfullerenes has long been suspected, synthetic efforts have yet to yield successful results. Here, we report the realization of two isobuckminsterfullerenes by means of chlorination of the respective C2v- and Cs-symmetric C60 cages. These chlorinated species, #1,809C60Cl8(1) and #1,804C60Cl12(2), were isolated in experimentally useful yields. Structural characterization by crystallography unambiguously established the unique pentagon-pentagon ring fusions. These distinct structural features are directly responsible for the regioselectivity observed in subsequent substitution of chlorines, and also render these unprecedented derivatives of C60 isomers important for resolving the long-standing puzzle of fullerene formation by the Stone-Wales transformation scheme.