Electrospray and laser desorption ionization studies of C₆₀O and isomers of C₆₀O₂

The reaction of C₆₀ with ozone in toluene results in the formation of C₆₀ oxides. C₆₀O and two isomers of C₆₀O₂ were isolated; they both have the 423 nm absorption peak characteristic of an epoxide structure between adjacent 6,6-rings in C₆₀. Intact molecular ions are generated by electrospray ionization (ESI) without fragmentation. The enhanced ESI sensitivity of the higher oxides reflects the increase in electron affinity upon oxidation. In contrast to ESI, odd-numbered fragments are observed in laser desorption ionization (LDI) of C₆₀O. The two isomers of C₆₀O₂ show different intensity distributions of the same fragment ions in LDI, suggesting different distances between the two oxygen atoms in them. Mechanisms are proposed for the formation of the two isomeric forms of C₆₀O₂ and for mass spectrometric fragmentation processes.