title: 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@C(s)(6)-C82, and Sm@C2(5)-C82.
abstract: Three isomers of Sm@C(82) that are soluble in organic solvents were obtained from the carbon soot produced by vaporization of hollow carbon rods doped with Sm(2)O(3)/graphite powder in an electric arc. These isomers were numbered as Sm@C(82)(I), Sm@C(82)(II), and Sm@C(82)(III) in order of their elution times from HPLC chromatography on a Buckyprep column with toluene as the eluent. The identities of isomers, Sm@C(82)(I) as Sm@C(s)(6)-C(82), Sm@C(82)(II) as Sm@C(3v)(7)-C(82), and Sm@C(82)(III) as Sm@C(2)(5)-C(82), were determined by single-crystal X-ray diffraction on cocrystals formed with Ni(octaethylporphyrin). For endohedral fullerenes like La@C(82), which have three electrons transferred to the cage to produce the M(3+)@(C(82))(3-) electronic distribution, generally only two soluble isomers (e.g., La@C(2v)(9)-C(82) (major) and La@C(s)(6)-C(82) (minor)) are observed. In contrast, with samarium, which generates the M(2+)@(C(82))(2-) electronic distribution, five soluble isomers of Sm@C(82) have been detected, three in this study, the other two in two related prior studies. The structures of the four Sm@C(82) isomers that are currently established are Sm@C(2)(5)-C(82), Sm@C(s)(6)-C(82), Sm@C(3v)(7)-C(82), and Sm@C(2v)(9)-C(82). All of these isomers obey the isolated pentagon rule (IPR) and are sequentially interconvertable through Stone-Wales transformations.
authors.affiliation: College of Materials Science and Engineering, China Jiliang University, Hangzhou 310018, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Yang
authors.forename: Hongxiao
authors.initials: H
authors.lastname: Jin
authors.forename: Xinqing
authors.initials: X
authors.lastname: Wang
authors.forename: Ziyang
authors.initials: Z
authors.lastname: Liu
authors.forename: Meilan
authors.initials: M
authors.lastname: Yu
authors.forename: Fukun
authors.initials: F
authors.lastname: Zhao
authors.forename: Brandon Q
authors.initials: BQ
authors.lastname: Mercado
authors.forename: Marilyn M
authors.initials: MM
authors.lastname: Olmstead
authors.forename: Alan L
authors.initials: AL
authors.lastname: Balch