ja304867j_si_001.cif (79.65 kB)
X‑ray Crystallographic Characterization of New Soluble Endohedral Fullerenes Utilizing the Popular C82 Bucky Cage. Isolation and Structural Characterization of Sm@C3v(7)‑C82, Sm@Cs(6)‑C82, and Sm@C2(5)‑C82
dataset
posted on 2016-02-20, 13:16 authored by Hua Yang, Hongxiao Jin, Xinqing Wang, Ziyang Liu, Meilan Yu, Fukun Zhao, Brandon Q. Mercado, Marilyn M. Olmstead, Alan L. BalchThree isomers of Sm@C82 that are soluble in
organic
solvents were obtained from the carbon soot produced by vaporization
of hollow carbon rods doped with Sm2O3/graphite
powder in an electric arc. These isomers were numbered as Sm@C82(I), Sm@C82(II), and Sm@C82(III) in
order of their elution times from HPLC chromatography on a Buckyprep
column with toluene as the eluent. The identities of isomers, Sm@C82(I) as Sm@Cs(6)-C82, Sm@C82(II) as Sm@C3v(7)-C82, and Sm@C82(III) as Sm@C2(5)-C82, were
determined by single-crystal X-ray diffraction on cocrystals formed
with Ni(octaethylporphyrin). For endohedral fullerenes like La@C82, which have three electrons transferred to the cage to produce
the M3+@(C82)3– electronic
distribution, generally only two soluble isomers (e.g., La@C2v(9)-C82 (major) and La@Cs(6)-C82 (minor)) are observed. In contrast, with samarium, which
generates the M2+@(C82)2– electronic
distribution, five soluble isomers of Sm@C82 have been
detected, three in this study, the other two in two related prior
studies. The structures of the four Sm@C82 isomers that
are currently established are Sm@C2(5)-C82, Sm@Cs(6)-C82, Sm@C3v(7)-C82, and Sm@C2v(9)-C82. All of these isomers obey the isolated pentagon
rule (IPR) and are sequentially interconvertable through Stone–Wales
transformations.