Thermal stability and high temperature graphitization of bisazafullerene (C59N)(2) as studied by IR and Raman spectroscopy

Thermal stability and high-temperature degradation of pristine bisazafuller ene (C59N)(2) were analyzed by infrared and Raman spectroscopy in the tempe rature range from 300 to 745 K. The spectra showed a reversible temperature dependence up to 550 K. For higher temperatures an irreversible degradatio n into disordered graphite was found. Approximately 55% of the material res isted a thermal treatment of 745 K for several hours. A mechanism involving a low stationary concentration of C59N. monomer radical species and a slow graphitization is proposed for the thermolysis of the material. The remark able thermal stability of pristine bisazafullerene (C59N)(2) is ascribed to the low stability of the C59N. monomer radical species, the high activatio n energy for graphitization, and the absence of other reaction partners und er high vacuum conditions.