An extensive family of oxide cluster fullerenes (OCFs) Sc2O@C(2n) (n = 35-47) has been facilely produced for the first time by introducing CO2 as the oxygen source. Among this family, Sc2O@C-70 was identified as the smallest OCF and therefore isolated and characterized by mass spectrometry, (45)Sc nuclear magnetic resonance, UV-vis-near-infrared absorption spectroscopy, cyclic voltammetry, and density functional theory calculations.
The combined experimental and computational studies reveal a non-isolated pentagon rule isomer Sc2O@C-2(7892)-C-70 with reversible oxidative behavior and lower bandgap relative to that of Sc2S@C-2(7892)-C-70, demonstrating a typical example of unexplored OCF and underlining its cluster-dependent electronic properties.