New cycloadducts were obtained by the reaction of C-60 with pyrazolidi
nium ylides and -5-arylimino-2-phenyl-1,2,4-thiadiazolidin-3-ones, res
pectively. The structures of the heterocyclic fullerene derivatives we
re characterized using liquid secondary ion mass spectrometry (LSIMS).
Metastable fragmentations studied in linked scan experiments are disc
ussed.