TIMS and MALDI TOF of endohedral Li-n"C-70 (n=1-3) metallofullerenes

Abstract

Using the ion implantation technique (introducing negatively charged fullerene into a low temperature lithium plasma column by a strong axial magnetic field) endohedral fullerenes Li"C-70, Li-2"C-70 and Li-3"C-70 were produced. Mass spectral studies (both TIMS-thermal ionization mass spectrometry and MALDI TOF MS - matrix assisted laser desorption ionization time-of-flight mass spectrometry) of these endohedral fullerenes provided detailed structural and reactivity information about these unusual species. The fragmentation of the obtained ions is shown to be by a multiple C-2 loss (shrink-wrap mechanism). According to the fact that more atoms in the fullerene make the produced endohedral less stable, Li-3"C-70 shows a big degree of instability. The presence of Li-3"C-70 was observed on MALDI TOF MS.