Investigation of the photooxidation of [60]fullerene for the presence of the [5,6]-open oxidoannulene C60O isomer

The study of [60]fullerene oxidation reactions has played a major role in fullerene science. The parent fullerene epoxide (1) has been the subject of extensive experimental and theoretical study. A recent report described the discovery of a new monooxide isomer, [5,6]-open oxidoannulene (2). We have reinvestigated the photooxygenation of [60]fullerene to determine whether 2 forms in addition to epoxide 1. Isomer 2 is not detected via 13C NMR and HPLC analysis in the singlet oxygen sensitized [60]fullerene photolysis reaction.