Gas-Phase Ion-Molecule Chemistry of Fullerene Cations and Dications with Propene, 1-Butene, and Isobutene

The gas-phase ion-molecule reactions of C[sub n][sup +] and C[sub n][sup 2+] (N = 54, 56, 60, and 70) with isobutene were investigated by utilizing a triple quadrupole mass spectrometer. In addition, the ion chemistry of C[sub 60][sup +] and C[sub 60][sup 2+] with propene and 1-butene was investigated. The various ion-molecule reactions observed were highly dependent on the gas cell pressure and the collision energy of the primary ions. The product ions observed were governed primarily by associative and partial charge transfer reactions. The isomeric form of C[sub 4]H[sub 8] as well as the size of the fullerene ion affected the reactions observed. For example, 1-butene readily adds to C[sub 60][sup 2+], while isobutene adducts were not detected. Also, fullerene cations with adjacent five-membered rings (n = 54, 56 and 58) react with isobutene to produce C[sub n](C[sub 4]H[sub 8])[sup +] while C[sub 60][sup 2+] and C[sub 70][sup 2+] do not. 48 refs., 4 figs., 2 tabs.