Double functionalization of a fullerene in drastic arc-discharge conditions: synthesis and formation mechanism of C2v(2)-C78Cl6(C5Cl6)

Abstract Arc-discharge of graphite is the most prevalent technique for synthesis of novel fullerenes, but the extreme conditions of the carbon arc prevent any currently available instrument from detecting the reaction species inside. To detour the difficulties for probing the derivatization mechanism in the drastic arc-discharge conditions, C 78 Cl 6 (C 5 Cl 6 ) with prototypical C 2v (2)-C 78 cage has been isolated and characterized in the products of the chlorine-involving carbon arc. The structure of C 2v (2)-C 78 Cl 6 (C 5 Cl 6 ), featuring with fullerene C 2v (2)-C 78 doubly functionalized by chlorine atoms and perchlorinated cyclopentadiene, has been identified by X-ray crystallography. Confirmed by standard Density Functional Theory (DFT) calculations and Car-Parrinello simulations as well as mass spectrometry, the fullerene core has been revealed to form firstly followed then by reaction with chlorine atoms and afterwards with perchlorinated cyclopentadiene, with implication about stepwise reaction temperatures and sequences for the formation of fullerenes and their derivatives in the otherwise inaccessible extreme conditions of the carbon arc.