Separation and Characterization of C70(C14H10) and C70(C5H6) from an Acetylene–Benzene–Oxygen Flame

Abstract

Although derivatives of fullerenes are prevalent in the fullerene-producing flame, the chemistry of these derivatives has rarely been discussed in the previous literature. In this paper, two D5h-C70 derivatives, C70(C14H10) and C70(C5H6), were isolated from the soot of an acetylene–benzene combustion. On the basis of detailed MS, NMR, IR, and UV/vis analyses in combination with DFT calculations, the cycloadduct structures of C70(C14H10) and C70(C5H6) were identified. Both the anthracene (C14H10) and the cyclopentadiene (C5H6) adducts, supposed as the intermediate species produced during the combustion process, were characterized to bond at a [6,6] ring junction at the end of the olivary C70 cage. The present work exemplifies the capture of possible intermediates by the C70 fullerene from the flame and thus provides insight into the mechanism responsible for the formation of fullerene-containing soot.