Thermal stability of the heterofullerene (C59N)X for X=C59N,H.

The stability of the azafullerenes of the type (C59N)X was studied by using IR, mass spectroscopy, optical and Raman experiments. X represents either hydrogen or an other cage of C59N. Experimental data indicate thermal stability of the solid phase of the dieter up to 600 K followed by very slow degradation extending beyond 700 K. This is compared to our latest results on the temperature stability of C59HN which was found to be stable only up to 540 K. A sudden change in the spectra at this temperature gives evidence for a transition to a new air stable phase. Since the mass spectra show no loss of hydrogen the new Phase is claimed to be polymerized C59HN. When heated in vacuum to about 700 K this phase dimerizes into (C59N)(2).