Mixed Dimetallic Cluster Fullerenes: ScGdO@ C_3v(8)-C₈₂ and ScGdC₂@ C_2v(9)-C₈₂

Mixed-metal cluster fullerenes have been extensively studied in recent years for their rich structural variability of the encaged clusters and have shown great potential in applied studies such as biomedicine and molecular electronic devices. However, the studies in this field have mostly concentrated on the nitride cluster fullerene, and very few other types of mixed-metal cluster fullerenes have been reported so far. Herein, we report the synthesis and isolation of the first mixed-metal oxide cluster fullerene, ScGdO@C₈₂, and a novel mixed dimetallic carbide cluster fullerene, ScGdC₂@C₈₂. Spectroscopic and electrochemical studies combined with density functional theory (DFT) calculations assigned the molecular structure of the two cluster fullerenes (CFs) to ScGdO@ C_3v(8)-C₈₂ and ScGdC₂@ C_2v(9)-C₈₂, respectively. DFT calculations also suggested that these two mixed-metal clusters are likely to be found in any of the three isolated pentagon rule C_s(6)-C₈₂, C_3v(8)-C₈₂ and/or C_2v(9)-C₈₂ cages. The electrochemical studies show that the electrochemical gap of ScGdO@ C_3v(8)-C₈₂ and ScGdC₂@ C_2v(9)-C₈₂ are 1.49 and 1.08 V. Moreover, comparative studies of ScGdO@ C_3v(8)-C₈₂ and Sc₂O@ C_3v(8)-C₈₂, ScGdC₂@ C_2v(9)-C₈₂ and Sc₂C₂@ C_2v(9)-C₈₂ showed that, despite their close structural resemblance, the replacement of one Sc ion by a Gd ion resulted in notable changes in their electrochemical behaviors as well as their ⁴⁵Sc NMR spectra.