Contrasting Behaviors of Metal Fullerides C₆₀Rh<i>_x</i> and C₆₀M<i>_x</i> (M = La, Y) in the Metallofullerene Formation by Laser Ablation

Abstract

Contrasting behaviors of Rh with Y(La) in the formation of metallofullerenes by excimer laser ablation of metal fullerides C 60 Rh x and C 60 M x (M = La, Y) were observed. For Rh, two sequences of rhodium metallofullerenes, C 2 n Rh and C 2 n +1 Rh with even and odd numbers of carbon atoms, are formed in both the negative and positive ion channels, but for La and Y, only the metallofullerene sequence with even numbers of carbon atoms is formed and only in the positive ion channel. Evidence of the encapsulation of La and Y atoms in fullerene cages forming endohedral fullerenes has been observed, whereas the Rh atom is most probably incorporated into the network of the fullerene cage or pseudo-fullerene forming substitutional metallofullerenes. Density functional theory calculation was performed to determine the structures of the model metallofullerenes C 53 Rh and C 54 M (M = Rh and Y). The calculated results are in general consistent with the experimental observations.