1236299-90-3Relevant academic research and scientific papers
Self-sensitized photooxygenation of a C60-cycloheptatriene dyad to form norcaradiene-derived endoperoxides
Hanamura, Masaaki,Kamada, Jun,Amano, Akiyo,Takeuchi, KeN'Ichi,Okazaki, Takao,Hirai, Katsuyuki,Kitagawa, Toshikazu
, p. 3257 - 3264 (2010)
The [60]fullerene-cycloheptatriene dyad 1 readily underwent [4+2] cycloaddition of molecular oxygen at the cycloheptatriene moiety to give endoperoxides 5-e.xo and 5-endo. The involvement of singlet oxygen was verified by the complete inhibition of oxygenation on addition of -diazabicyclo[2.2.2] octane (DABCO), which is an efficient singlet-oxygen quencher. The observed facile oxygenation, was attributed to both the strong photosensitizing ability of the fuller-ene cage and to the valence isomerization of 1 to the norcaradiene form, which was facilitated by the bulky ierf-butyl groups. Competitive oxygenation of 1 and a related, cycloheptatriene lacking the fullerenyl group (2) resulted in the formation of endoperoxides of the two molecules in comparable yields. This result demonstrates that the cycloaddition is not an in-cage reaction but occurs after the singlet oxygen has diffused from the solvent cage.
