title: Carbon arc production of heptagon-containing fullerene[68].
abstract: A carbon heptagon ring is a key unit responsible for structural defects in sp(2)-hybrized carbon allotropes including fullerenes, carbon nanotubes and graphenes, with consequential influences on their mechanical, electronic and magnetic properties. Previous evidence concerning the existence of heptagons in fullerenes has been obtained only in off-line halogenation experiments through top-down detachment of a C(2) unit from a stable fullerene. Here we report a heptagon-incorporating fullerene C(68), tentatively named as heptafullerene[68], which is captured as C(68)Cl(6) from a carbon arc plasma in situ. The occurrence of heptagons in fullerenes is rationalized by heptagon-related strain relief and temperature-dependent stability. (13)C-labelled experiments and mass/energy conservation equation simulations show that heptafullerene[68] grows together with other fullerenes in a bottom-up fashion in the arc zone. This work extends fullerene research into numerous topologically possible, heptagon-incorporating isomers and provides clues to an understanding of the heptagon-involved growth mechanism and heptagon-dependent properties of fullerenes.
authors.affiliation: State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
authors.forename: Yuan-Zhi
authors.initials: YZ
authors.lastname: Tan
authors.forename: Rui-Ting
authors.initials: RT
authors.lastname: Chen
authors.forename: Zhao-Jiang
authors.initials: ZJ
authors.lastname: Liao
authors.forename: Jia
authors.initials: J
authors.lastname: Li
authors.forename: Feng
authors.initials: F
authors.lastname: Zhu
authors.forename: Xin
authors.initials: X
authors.lastname: Lu
authors.forename: Su-Yuan
authors.initials: SY
authors.lastname: Xie
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Rong-Bin
authors.initials: RB
authors.lastname: Huang
authors.forename: Lan-Sun
authors.initials: LS
authors.lastname: Zheng