PROPOSED FULLERENE PRECURSOR CORANNULENE IDENTIFIED IN FLAMES BOTH IN THE PRESENCE AND ABSENCE OF FULLERENE PRODUCTION

Corannulene, C20H10, a bowl-shaped polycyclic aromatic hydrocarbon whose curvature and carbon framework are similar to those of fullerenes, has been widely hypothesized to be a fullerene precursor but has never been identified in flames, either in the presence or absence of fullerene production. In research on the mechanism and prevalence of fullerene formation in flames, we have identified corannulene in fullerene-producing flames and also in conventional flames that do not produce fullerenes. The identification was achieved using a combination of analytical methods including high performance liquid chromatography with UV-vis spectrometric detection, and gas chromatography coupled with infrared and mass spectrometric detection. The presence of corannulene in fullerene-forming flames is consistent with the hypothesis that corannulene is a fullerene precursor. The presence of corannulene in fullerene-deficient flames does not necessarily contradict this hypothesis and instead may suggest that at least some stages of fullerene formation chemistry are more generally operative in flames than had previously been known.