Reactivity of Further Fullerenes

Fullerenes smaller than inevitably contain neighboring five-membered rings. Therefore, they are particularly strained and highly energetic, which should reflect in an increased reactivity. Problem is, however, that these species cannot be isolated at all or in infinitely small quantities only, and any material actually obtained 

Nevertheless, a derivative of the fullerene C50 has been isolated just recently. C50 is the first fullerene with a maximum of two five-membered rings each in adjacent position. In even smaller species groups of three five-membered rings must at least partly be immediate neighbors, which means an additional destabilization. C50 possesses a completely closed electron shell. This results in a more distinct aromatic character than in open-sheU fuUerenes. 

The preparation and reactivity of C36 have been studied, too. Regarding stability it is situated between fuUerenes and rings and accordingly should show an interesting chemical behavior. Its most striking feature is the tendency to form intermolecular bonds, thus generating di- and trimers. According to different 

---