Abstract
Although a non-IPR fullerene cage is common for endohedral cluster fullerenes, it is very rare for conventional endofullerenes M@C-2n, probably because of the minimum geometry fit effect of the endohedral single metal ion. In this work, we report on a new non-IPR endofullerene Sm@C-2v(19138)-C-76, including its structural and electrochemical features.
A combined study of single-crystal X-ray diffraction and DFT calculations not only elucidates the non-IPR cage structure of C-2v(19138)-C-76 but also suggests that the endohedral Sm2+ ion prefers to reside along the C-2 cage axis and close to the fused pentagon unit in the cage framework, indicative of a significant metal-cage interaction, which alone can stabilize the non-IPR cage. Furthermore, electrochemical studies reveal the fully reversible redox behaviors and small electrochemical gap of Sm@C-2v(19138)-C-76, which are comparable to those of IPR species Sm@D-3h-C-74.