Detection of a Family of Gadolinium-Containing Endohedral Fullerenes and the Isolation and Crystallographic Characterization of One Member as a Metal−Carbide Encapsulated inside a Large Fullerene Cage

A series of di-gadolinium endohedrals that extends from Gd2C90 to Gd2C124 has been detected by mass spectrometry of the o-dichlorobenzene extract of the carbon soot produced by direct current arcing of graphite rods filled with a mixture of Gd2O3 and graphite powder. Chromatographic separation has led to the isolation of pure samples of two isomers of Gd2C94 and the complete series from Gd2C96 to Gd2C106. Endohedral fullerenes of the type M2C2n can exist as the conventional endohedral, M2@C2n, or as the carbide-containing endohedral, M2C2@C2n−2. Crystallographic characterization of the more rapidly eluting isomer of Gd2C94 reveals that it possesses the carbide structure, Gd2C2@D3(85)-C92. Computational studies suggest that the more slowly eluting isomer of Gd2C94 may be a conventional endohedral, Gd2@C2(121)-C94

Detection of a Family of Gadolinium-Containing Endohedral Fullerenes and the Isolation and Crystallographic Characterization of One Member as a Metal−Carbide Encapsulated inside a Large Fullerene Cage

A series of di-gadolinium endohedrals that extends from Gd2C90 to Gd2C124 has been detected by mass spectrometry of the o-dichlorobenzene extract of the carbon soot produced by direct current arcing of graphite rods filled with a mixture of Gd2O3 and graphite powder. Chromatographic separation has led to the isolation of pure samples of two isomers of Gd2C94 and the complete series from Gd2C96 to Gd2C106. Endohedral fullerenes of the type M2C2n can exist as the conventional endohedral, M2@C2n, or as the carbide-containing endohedral, M2C2@C2n−2. Crystallographic characterization of the more rapidly eluting isomer of Gd2C94 reveals that it possesses the carbide structure, Gd2C2@D3(85)-C92. Computational studies suggest that the more slowly eluting isomer of Gd2C94 may be a conventional endohedral, Gd2@C2(121)-C94

Isolation and Structural Characterization of Two Very Large, and Largely Empty, Endohedral Fullerenes: Tm@<i>C</i>_3<i>v</i>-C₉₄ and Ca@<i>C</i>_3<i>v</i>-C₉₄

The structures of two newly synthesized endohedral fullerenes, Tm@C3v-C94 and Ca@C3v-C94, have been determined by single crystal X-ray diffraction on samples cocrystallized with NiII(octaethylporphyrin). Both compounds exhibit the same cage geometry and conform to the isolated pentagon rule (IPR). The metal ions within these rather large cages are localized near one end and along the C3 axis. While the calcium ion is situated over a C−C bond at a 6:6 ring junction, the thulium ion is positioned above a six-membered ring of the fullerene

Isolation and Structural Characterization of Two Very Large, and Largely Empty, Endohedral Fullerenes: Tm@<i>C</i>_3<i>v</i>-C₉₄ and Ca@<i>C</i>_3<i>v</i>-C₉₄

The structures of two newly synthesized endohedral fullerenes, Tm@C3v-C94 and Ca@C3v-C94, have been determined by single crystal X-ray diffraction on samples cocrystallized with NiII(octaethylporphyrin). Both compounds exhibit the same cage geometry and conform to the isolated pentagon rule (IPR). The metal ions within these rather large cages are localized near one end and along the C3 axis. While the calcium ion is situated over a C−C bond at a 6:6 ring junction, the thulium ion is positioned above a six-membered ring of the fullerene