Formation of Metallofullerenes by Laser Ablation of Metal-containing Fullerene Materials

摘要

Photofragmentation of metal fullerides C_(60)M_x (M = Sm, Pt) and composite materials composed of M_2O_3 (M = La, Y) and ozonized C_(60) precipitate (designated as C_(60)+ O_3 below) has been studied by excimer laser ablation-TOF mass spectrometry. In the laser ablation of metal-fullerene clusters C_(60)M_x, metallofullerenes of the type MC_n (n in the fullerene region) have been observed in both ionic modes. [C_(59)M]~+ and [C_(59)M]~- are the most prominent metallofullerenes depicted in the positive and negative mass spectra respectively. The metal atom is supposed to be incorporated into the network of the fullerene cage to replace one carbon atom of the cage forming the heterofullerene. In the case of the composite material La_2O_3/C_(60) + O_3 and Y_2O_3/C_(60) + O_3, under nearly the same experimental conditions, evidence of the encapsulation of La and Y atoms in fullerene cages forming endohedral fullerenes have been observed. No La (or Y)-containing heterofullerene has been detected.