A transformation map covering as many as 98% of metallofullerenes with clear C2n (2n = 74–86) cage structures is uncovered with C2(27)-C88, C1(7)-C86, C2(13)-C84 and C2(11)-C84 as key links.
Encapsulating one to three metal atoms or a metallic cluster inside fullerene cages affords endohedral metallofullerenes (EMFs) classified as mono‐, di‐, tri‐, and cluster‐EMFs, respectively. Although the coexistence of various EMF species in soot is common for rare‐earth metals, we herein report that europium tends to prefer the formation of mono‐EMFs. Mass spectroscopy reveals that mono‐EMFs (Eu@C2n) prevail in the Eu‐containing soot. Theoretical calculations demonstrate that the encapsulation energy of the endohedral metal accounts for the selective formation of mono‐EMFs and rationalize similar observations for EMFs containing other metals like Ca, Sr, Ba, or Yb. Consistently, all isolated Eu‐EMFs are mono‐EMFs, including Eu@D3h(1)‐C74, Eu@C2v(19138)‐C76, Eu@C2v(3)‐C78, Eu@C2v(3)‐C80, and Eu@D3d(19)‐C84, which are identified by crystallography. Remarkably, Eu@C2v(19138)‐C76 represents the first Eu‐containing EMF with a cage that violates the isolated‐pentagon‐rule, and Eu@C2v(3)‐C78 is the first C78‐based EMF stabilized by merely one metal atom.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.