TANDEM MASS-SPECTROMETRY STUDIES OF OXYGEN INTERACTIONS WITH FULLERENES AND METALLOFULLERENES

The reaction products of oxygen with fullerenes and metallofullerenes have been characterized by thermal desorption mass spectrometry and lo w energy collisional activation on a triple quadrupole mass spectromet er. C60O, which is present in fullerene soot, fragments primarily with the loss of O, although CO loss can be observed at higher collision e nergies. Fragmentation of C60On- adducts, formed by reactions with oxy gen in the chemical ionization source or by reactive collisions with O -2 in the collision cell, is characterized by CO loss at relatively lo w energies, followed by CO2 loss and loss of 2CO. The results indicate that O-2 must interact as the intact diatomic species in order to ini tiate fragmentation of the fullerene cage, consistent with other repor ts in the literature. O-3 induced fragmentation occurs in a similar fa shion, and the results may explain the first step in the recently repo rted formation of higher, odd-numbered fullerenes (e.g. C-119) in ozon olysis. Studies with metallofullerenes indicate that the extractable m etallofullerenes (LaC82, La2C80) are less reactive toward oxygen than their less extractable counterparts (LaC60, LaC70). The stability of L aC82 and La2C80 was demonstrated by the formation of He uptake product s (e.g. He@LaC82) in high energy collisions with He in a hybrid (BEqQ) mass spectrometer.