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

Abstract

A series of di-gadolinium endohedrals that extends from Gd(2)C(90) to Gd(2)C(124) 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 Gd(2)O(3) and graphite powder. Chromatographic separation has led to the isolation of pure samples of two isomers of Gd(2)C(94) and the complete series from Gd(2)C(96) to Gd(2)C(106). Endohedral fullerenes of the type M(2)C(2n) can exist as the conventional endohedral, M(2)@C(2n), or as the carbide-containing endohedral, M(2)C(2)@C(2n-2). Crystallographic characterization of the more rapidly eluting isomer of Gd(2)C(94) reveals that it possesses the carbide structure, Gd(2)C(2)@D(3)(85)-C(92). Computational studies suggest that the more slowly eluting isomer of Gd(2)C(94) may be a conventional endohedral, Gd(2)@C(2)(121)-C(94).

Vibrational spectrum of the endohedralY2C2@CBurke1, Chan2, Williams3 et al. 2011Phys. Rev. B172160View full textAdd to dashboardCite

“…Endohedral fullerenes 1 or endofullerenes created by arc-vaporization 2 have been shown to encapsulate clusters of the form M 2 C 2 (M = Sc, Y, and several lanthanides) 3 . Within these molecules, entirely novel core species are stable and generate completely new behavior.…”

Investigation ofGd3N@C2n (40≤n≤44)Burke1, Chan2, Williams3 et al. 2010Phys. Rev. B28070View full textAdd to dashboardCite

“…It is interesting to note that previous x-ray data have distinguished Gd 3 N@C 80 , which obeys the IPR and contains a pyramidal Gd 3 N unit, from Gd 3 N@C 82 and Gd 3 N@C 84 which contain planar Gd 3 units and carbon cages that do not follow the IPR. 2,8 Although no x-ray or NMR data has been conducted for Gd 3 which identifies the C 80 cage modes. The frequency of the M-cage stretching mode is increased to 195.6 cm −1 for the yttrium complex, 2,38 due to the change in reduced mass ͑32.7% decrease͒, and decreased to 155.9 cm −1 for the lutetium complex, due to the change in reduced mass ͑7.0% increase͒.…”

“…1,2 Potential applications include electronic devices, 3 organic solar cells, 4 spin-based quantum computing, 5,6 and medicine, [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] specifically contrast agents for magnetic-resonance imaging ͑MRI͒ as well as radiopharmaceutical candidates. 8,9 Endofullerenes created by an arc-vaporization technique 23 have been known to encapsulate clusters of the form M 3 N ͑M = Sc, Y, and several lanthanides͒.…”

“…8,9 Endofullerenes created by an arc-vaporization technique 23 have been known to encapsulate clusters of the form M 3 N ͑M = Sc, Y, and several lanthanides͒. 2,8 The isolation of magnetic and radioactive Gd 3 N@C 2n molecules has received much interest due to their application as MRI contrast agents and the confinement of three paramagnetic Gd ions in a relatively small space ͑ϳ1 nm͒.…”

“…2,27 Although certain gadolinium endofullerenes have been isolated and studied by x-ray diffraction, vibrational spectroscopy has not been performed on a number of species. 2,8 In this paper, we present a detailed Raman and inelastic electron tunneling spectroscopy ͑IETS͒ analysis of Gd 3 N@C 80 , as well as conductance measurements demonstrating a Kondo effect. Raman analysis of Gd 3 N@C 2n ͑40 Յ n Յ 44͒ has been performed, as well as Y 3 N@C 80 , Lu 3 N@C 80 , and Y 3 N@C 88 for comparison.…”