Encapsulation of a scandium trimer in C82

Shinohara, Hisanori; Sato, Hiroyasu; Ohkohchi, Masato; Ando, Yoshinori; Kodama, Tohru; Shida, Tadamasa; Kato, Tatsuhisa; Saito, Yahachi

doi:10.1038/357052a0

Cited by 335 publications

(153 citation statements)

References 12 publications

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“…For the Sc 2 C 84 metallofullerene, three isomers (I, II, and III) have been isolated. [8,9] The most abundant isomer, Sc 2 C 84 (III), was characterized and discussed in terms of its X-ray photoelectron, [10] 13 C NMR, [9] 45 Sc NMR, [11] IR, [12] and Raman [13] spectroscopic measurements, powder X-ray analysis, [14] and theoretical calculations [15] on the premise that two Sc atoms were encapsulated inside the D 2d isomer of C 84 . However, we have very recently observed an improved 13 C NMR spectrum of Sc 2 C 84 (III) that shows a total of 17 lines (11 full-intensity signals, five half-intensity signals, and one 1/6-intensity signal), [16] unlike the previous 13 C NMR study.…”

mentioning

confidence: 99%

Experimental and Theoretical Studies of the Scandium Carbide Endohedral Metallofullerene Sc₂C₂@C₈₂ and Its Carbene Derivative

et al. 2007

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Endohedral metallofullerenes have attracted special attention as new spherical molecules with unique properties that are unexpected for empty fullerenes. [1][2][3] Much work has been carried out on metallofullerenes with Sc, Y, and La atoms encapsulated inside C 82 and C 84 cages. Among these, scandium carbide endohedral metallofullerenes, such as Sc 2 C 2 @ C 84 [4,5] and Sc 3 C 2 @C 80 , [6,7] are the most interesting because of the encapsulation of the C 2 unit together with several metal atoms, which is very important to the chemistry of scandium carbide endohedral metallofullerenes. For the Sc 2 C 84 metallofullerene, three isomers (I, II, and III) have been isolated. [8,9] The most abundant isomer, Sc 2 C 84 (III), was characterized and discussed in terms of its X-ray photoelectron, [10] 13 C NMR, [9] 45 Sc NMR, [11] IR, [12] and Raman [13] spectroscopic measurements, powder X-ray analysis, [14] and theoretical calculations [15] on the premise that two Sc atoms were encapsulated inside the D 2d isomer of C 84 . However, we have very recently observed an improved 13 C NMR spectrum of Sc 2 C 84 (III) that shows a total of 17 lines (11 full-intensity signals, five half-intensity signals, and one 1/6-intensity signal), [16] unlike the previous 13 C NMR study.[9] The newly observed 13 C NMR pattern is not explained by placing two Sc atoms inside any of the isomers of C 84 that satisfy the isolated-pentagon rule. We have suggested that the 13 C NMR pattern is explained by the fact that two C atoms as well as two Sc atoms are encapsulated inside the C 3v isomer of C 82 . Very recently, it has been found that the Sc 2 C 2 @C 82 structure is correct by MEM (maximum-entropy method)/Rietveld analysis of synchrotron X-ray powder diffraction data, though the Sc 2 @C 84 structure was once determined by MEM/Rietveld analysis. [17] To verify that Sc 2 C 84 (III) is a scandium carbide metallofullerene (Sc 2 C 2 @C 82 (III)), X-ray single-crystal analysis and density functional calculations were carried out. The structure of Sc 2 C 2 @C 82 (III), optimized by density functional calculations, is shown in Figure 1.[18] The electronic structure is described as (Sc 2 C 2 ) 4+ C 82 4À as a result of four-electron transfer from Sc 2 C 2 to C 82 . The structure is most stable when the encapsulated Sc 2 C 2 moiety has a bent structure and two Sc atoms are not equivalent. This result seems contradictory to the 13 C NMR spectrum (16 signals), which shows that Sc 2 C 2 @C 82 (III) has C 3v symmetry, and the 45 Sc NMR spectrum (only one signal), which shows that the two Sc atoms are equivalent. This situation is explained by the fact that the Sc and C atoms in Sc 2 C 2 are allowed to rotate and move rapidly on the NMR time scale. The redox potentials of Sc 2 C 2 @C 82 (III), measured by cyclic voltammetry (CV) and

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confidence: 99%

Experimental and Theoretical Studies of the Scandium Carbide Endohedral Metallofullerene Sc₂C₂@C₈₂ and Its Carbene Derivative

et al. 2007

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“…[1][2][3][4][5][6][7][8] Many experimental results have shown that a group-III metal ͑M ϭSo, Y, La͒ or lanthanide atom could be attached to a fullerene C 82 molecule. 1-8 X-ray absorption fine-structure ͑EXAFS͒ studies on Y@C 82 have provided strong evidence that the metal atom is located inside the fullerene cage.…”

Section: Introductionmentioning

confidence: 99%

Nucleation of endohedral metallofullereneNd@C82onC
Lin
¹
,
Huang
²
,
Yang
³

et al. 1998
Phys. Rev. B
19
2
16
0
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We have studied the initial stage growth of endohedral metallofullerene Nd@C 82 on crystalline C 60 films using in situ ultrahigh vacuum scanning tunneling microscopy. We find that Nd@C 82 molecules aggregate into two-dimensional close-packed configurations. Over 60% of molecules form triangle-shaped trimers with identical orientation with respect to the underlying C 60 films. Our observations are attributed to a permanent dipole moment of Nd@C 82 molecules. We also use a dipole-dipole interaction model to calculate their binding energy and the result shows that the dipole moments of Nd@C 82 molecules will displace off the molecular center while they form trimers. ͓S0163-1829͑98͒02728-3͔

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“…They found, using laser vaporization and mass spectra, that both La and La 2 form endohedral fullerenes. Later, Shinohara and coworkers have studied the production of yttrium endohedral YC 60 [10] and scandium endohedral ScC 60 [11] using arc and laser vaporization of metal-graphite composites in helium atmosphere. Kortan et al [12] found that a high concentration of calcium (Ca) doped C 60 experienced phase transitions from face-centered cubic to simple cubic via body-centered cubic.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, endohedral fullerene, a member of fullerene family with a dopant encaged within the sphere, has received remarkable attention in various experimental [9][10][11][12][13][14][15][16][17][18] and theoretical [19][20][21][22][23][24][25][26][27][28][29][30] investigations due to its exotic physical and chemical properties such as pseudoatom behavior, magnetism, and superconductivity. The incorporation of lanthanum (La) atom inside the cage of the C 60 structure has been experimentally investigated by Heath et al [9] to detect the existence of endohedral metallofullerene complexes.…”

Section: Introductionmentioning

confidence: 99%

Cerium-Doped Endohedral Fullerene: A Density-Functional Theory Study

AlZahrani

2012

ISRN Condensed Matter Physics

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First-principles total energy calculations of the structural and electronic properties of Ce-doped fullerene have been performed within the framework of the density functional theory at the generalized gradient approximation level. Among various locations, Ce atom was found to engage with the six-fold carbon ring. The total energy is found to significantly change as the Ce atom being shifted from the center of the cage toward the edge close to the six-membered ring where the total energy reaches its local minimum. Moreover, repulsive interaction between Ce atom and the cage components turns as the adatom directly interacts with the six C atoms of the ring. The lowest-energy CeC 60 geometry is found to have a binding energy of approximately 5.34 eV, suggesting strong interaction of the dopant with the cage members. Furthermore, fundamental key structural parameters and the total density of states of the optimized structure have been determined and compared with the available data.

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Encapsulation of a scandium trimer in C82

Cited by 335 publications

References 12 publications

Experimental and Theoretical Studies of the Scandium Carbide Endohedral Metallofullerene Sc₂C₂@C₈₂ and Its Carbene Derivative

Experimental and Theoretical Studies of the Scandium Carbide Endohedral Metallofullerene Sc₂C₂@C₈₂ and Its Carbene Derivative

Nucleation of endohedral metallofullereneNd@C82onC
Lin
¹
,
Huang
²
,
Yang
³

et al. 1998
Phys. Rev. B
19
2
16
0
View full text Add to dashboard Cite

Cerium-Doped Endohedral Fullerene: A Density-Functional Theory Study

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Encapsulation of a scandium trimer in C82

Cited by 335 publications

References 12 publications

Experimental and Theoretical Studies of the Scandium Carbide Endohedral Metallofullerene Sc2C2@C82 and Its Carbene Derivative

Experimental and Theoretical Studies of the Scandium Carbide Endohedral Metallofullerene Sc2C2@C82 and Its Carbene Derivative

Nucleation of endohedral metallofullereneNd@C82onCLin1, Huang2, Yang3 et al. 1998Phys. Rev. B192160View full textAdd to dashboardCite

Cerium-Doped Endohedral Fullerene: A Density-Functional Theory Study

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Experimental and Theoretical Studies of the Scandium Carbide Endohedral Metallofullerene Sc₂C₂@C₈₂ and Its Carbene Derivative

Experimental and Theoretical Studies of the Scandium Carbide Endohedral Metallofullerene Sc₂C₂@C₈₂ and Its Carbene Derivative

Nucleation of endohedral metallofullereneNd@C82onC
Lin
¹
,
Huang
²
,
Yang
³

et al. 1998
Phys. Rev. B
19
2
16
0
View full text Add to dashboard Cite