title: Isolation and Structure Determination of a Missing Endohedral Fullerene La@C70 through In Situ Trifluoromethylation.
abstract: D5h-symmetric fullerene C70 (D5h-C70) is one of the most abundant members of the fullerene family. One longstanding mystery in the field of fullerene chemistry is whether D5h-C70 is capable of accommodating a rare-earth metal atom to form an endohedral metallofullerene M@D5h-C70, which would be expected to show novel electronic properties. The molecular structure of La@C70 remains unresolved since its discovery three decades ago because of its extremely high instability under ambient conditions and insolubility in organic solvents. Herein, we report the single-crystal X-ray structure of La@C70(CF3)3, which was obtained through in situ exohedral functionalization by means of trifluoromethylation. The X-ray crystallographic study reveals that La@C70(CF3)3 is the first example of an endohedral rare-earth fullerene based on D5h-C70. The dramatically enhanced stability of La@C70(CF3)3 compared to La@C70 can be ascribed to trifluoromethylation-induced bandgap enlargement.
authors.affiliation: Department of Chemistry and Institute for Advanced Research, Nagoya University, Nagoya 464-8602 (Japan).
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Information and Basic Science, Nagoya City University, Nagoya 467-8501 (Japan).
authors.forename: Shinobu
authors.initials: S
authors.lastname: Aoyagi
authors.affiliation: Department of Chemistry and Institute for Advanced Research, Nagoya University, Nagoya 464-8602 (Japan).
authors.forename: Haruka
authors.initials: H
authors.lastname: Omachi
authors.affiliation: Department of Chemistry and Institute for Advanced Research, Nagoya University, Nagoya 464-8602 (Japan).
authors.forename: Ryo
authors.initials: R
authors.lastname: Kitaura
authors.affiliation: Department of Chemistry and Institute for Advanced Research, Nagoya University, Nagoya 464-8602 (Japan). noris@nagoya-u.jp.
authors.forename: Hisanori
authors.initials: H
authors.lastname: Shinohara
keywords: X-ray diffraction; density functional calculations; electronic structure; lanthanum; metallofullerenes