Thermoreversible polymerization. Formation of fullerene-diene oligomers and copolymers

Diels-Alder reaction of C-60 with bis-anthracene 3 provides linear copolymer 4. This material is stable at room temperature but undergoes reversion to the monomeric species upon heating. This thermal depolymerization process was observed at temperatures above 60 degrees C, with an activation energy of 17.1 kcal/mol. This process can be cycled multiply without degradation of the reactive functionalities. In addition to its thermal properties, this polymer retains the rich redox chemistry of the fulleroids. Electrochemical and EPR studies demonstrate copolymer 4 undergoes multiple reductions without decomposition to monomeric species.