Facile Access to Y₂C_2n (2n = 92–130) and Crystallographic Characterization of Y₂C₂@C₁(1660)-C₁₀₈: A Giant Nanocapsule with a Linear Carbide Cluster

A series of giant metallofullerenes Y 2 C 2 n (2 n = 92–130) have been successfully obtained through the treatment of the fraction enriched by 1,2-dichlorobenzene with SnCl 4 . Subsequent chromatographic separation gives a pure sample with a composition of Y 2 C 110 . Crystallographic results reveal that this endohedral takes the carbide form, namely Y 2 C 2 @ C 1 (1660)-C 108, representing as the largest metallofullerene that has been characterized by crystallography to date. Despite the disorder of the metal cluster, the major Y 2 C 2 adopts a previously predicted linear configuration, indicating that the compression of the internal cluster by the cage is almost negligible in this giant cage. Electrochemical studies suggest that Y 2 C 2 @ C 1 (1660)-C 108 is a good electron donor instead of an electron acceptor.