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The maximum pentagon separation rule provides a guideline for the structures of endohedral metallofullerenes

Nature Chemistry volume 2, pages 955–961 (2010)Cite this article

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Abstract

Fullerenes tend to follow the isolated pentagon rule, which requires that each of the 12 pentagons is surrounded only by hexagons. Over the past decade many violations to this rule were reported for endohedral fullerenes. Based on the ionic model M3N6+@C2n6− and the orbital energies of the isolated cages, in 2005 we formulated a molecular orbital rule to identify the most suitable hosting cages in endohedral metallofullerenes. Now, we give physical support to the orbital rule, and we propose the maximum pentagon separation rule, which can be applied to either isolated pentagon rule cages or to non-isolated pentagon rule cages with the same number of adjacent pentagon pairs. The maximum pentagon separation rule can be formulated as 'The electron transfer from the internal cluster to the fullerene host preferentially adds electrons to the pentagons; therefore, the most suitable carbon cages are those with the largest separations among the 12 pentagons'.

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Figure 1: X-ray structures showing typical endohedral metallofullerenes.
Figure 2: Relative stability for 823 isomers of C104 with respect to the IPSI.
Figure 3: Correlations between relative stability of the fullerene anions and the atomic charge localized on the pentagons, the IPSI and the electrostatic energy.
Figure 4: Schlegel diagrams and MEP representations for representative fullerenes.
Figure 5: Schematic representations of some fullerene fragments.

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References

  1. Krätschmer, W., Lamb, L. D., Fostiropoulos, K. & Huffman, D. R. Solid C60: a new form of carbon. Nature 347, 354–357 (1990).

    Article  Google Scholar 

  2. Beer, F., Gugel, A., Martin, K., Rader, J. & Mullen, K. High-yield reactive extraction of giant fullerenes from soot. J. Mater. Chem. 7, 1327–1330 (1997).

    Article  CAS  Google Scholar 

  3. Kroto, H. W. The stability of the fullerenes Cn, with n = 24, 28, 32, 36, 50, 60 and 70. Nature 329, 529–531 (1987).

    Article  CAS  Google Scholar 

  4. Kroto, H. W., Heath, J. R., O'Brien, S. C., Curl, R. E. & Smalley, R. E. C60: buckminsterfullerene. Nature 318, 162–164 (1985).

    Article  CAS  Google Scholar 

  5. Heath, J. R. et al. Lanthanum complexes of spheroidal carbon shells. J. Am. Chem. Soc. 107, 7779–7780 (1985).

    Article  CAS  Google Scholar 

  6. Akasaka, T. & Nagase, S. Endofullerenes: A New Family of Carbon Clusters (Springer, 2002).

    Book  Google Scholar 

  7. Stevenson, S. et al. Small-bandgap endohedral metallofullerenes in high yield and purity. Nature 401, 55–57 (1999).

    Article  CAS  Google Scholar 

  8. Stevenson, S. et al. Materials science: a stable non-classical metallofullerene family. Nature 408, 427–428 (2000).

    Article  CAS  Google Scholar 

  9. Chaur, M. N., Valencia, R., Rodriguez-Fortea, A., Poblet, J. M. & Echegoyen, L. Trimetallic nitride endohedral fullerenes: experimental and theoretical evidence for the M3N6+@C6−2n model. Angew. Chem. Int. Ed. 48, 1425–1428 (2009).

    Article  CAS  Google Scholar 

  10. Wang, C. R. et al. A scandium carbide endohedral metallofullerene: (Sc2C2)@C84 . Angew. Chem. Int. Ed. 40, 397–399 (2001).

    Article  CAS  Google Scholar 

  11. Iiduka, Y et al. Experimental and theoretical studies of the scandium carbide endohedral metallofullerene Sc2C2@C82 and its carbene derivative. Angew. Chem. Int. Ed. 46, 5562–5564 (2007).

    Article  CAS  Google Scholar 

  12. Iiduka, Y. et al. Structural determination of metallofullerene Sc3C82 revisited: a surprising finding. J. Am. Chem. Soc. 127, 12500–12501 (2005).

    Article  CAS  Google Scholar 

  13. Wang, S.-T. et al. Russian-doll-type metal carbide endofullerene: synthesis, isolation, and characterization of Sc4C2@C80 . J. Am. Chem. Soc. 131, 16646–16647 (2009).

    Article  CAS  Google Scholar 

  14. Stevenson, S. et al. A distorted tetrahedral metal oxide cluster inside an icosahedral carbon cage. Synthesis, isolation, and structural characterization of Sc4(μ3-O)2@Ih-C80 . J. Am. Chem. Soc. 130, 11844–11845 (2008).

    Article  CAS  Google Scholar 

  15. Mercado, B. Q. et al. A seven atom cluster in a carbon cage, the crystallographically determined structure of Sc4(μ3-O)3@Ih-C80 . Chem. Commun. 279–281 (2010).

  16. Dunsch, L. et al. Metal sulfide in a C82 fullerene cage: a new form of endohedral clusterfullerenes. J. Am. Chem. Soc. 132, 5413–5421 (2010).

    Article  CAS  Google Scholar 

  17. Lu, X. et al. Chemical understanding of a non-IPR metallofullerene: stabilization of encaged metals on fused-pentagon bonds in La2@C72 . J. Am. Chem. Soc. 130, 9129–9136 (2008).

    Article  CAS  Google Scholar 

  18. Yang, S. & Dunsch, L. Di- and tridysprosium endohedral metallofullerenes with cages from C94 to C100 . Angew. Chem. Int. Ed. 45, 1299–1302 (2006).

    Article  CAS  Google Scholar 

  19. Melin, F. et al. The large Nd3N@C2n (40 ≤ n ≤ 49) cluster fullerene family: preferential templating of a C88 cage by a trimetallic nitride cluster. Angew. Chem. Int. Ed. 46, 9032–9035 (2007).

    Article  CAS  Google Scholar 

  20. Mercado, B. Q. et al. Isolation and structural characterization of the molecular nanocapsule Sm2@D3d(822)-C104 . Angew. Chem. Int. Ed. 48, 9114–9116 (2009).

    Article  CAS  Google Scholar 

  21. Yang, H. et al. 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. J. Am. Chem. Soc. 130, 17296–17300 (2008).

    Article  CAS  Google Scholar 

  22. Che, Y. et al. Isolation and structural characterization of two very large, and largely empty, endohedral fullerenes: Tm@C3v-C94 and Ca@C3v-C94 . Inorg. Chem. 48, 6004–6010 (2009).

    Article  CAS  Google Scholar 

  23. Beavers, C. M. et al. An improbable, egg-shaped endohedral fullerene that violates the isolated pentagon rule. J. Am. Chem. Soc. 128, 11352–11353 (2006).

    Article  CAS  Google Scholar 

  24. Wang, C. R. et al. Materials science: C66 fullerene encaging a scandium dimer. Nature 408, 426–427 (2000).

    Article  CAS  Google Scholar 

  25. Tan, Y.-Z., Xie, S.-Y., Huang, R.-B. & Zheng, L.-S. The stabilization of fused-pentagon fullerene molecules. Nature Chem. 1, 450–460 (2009).

    Article  CAS  Google Scholar 

  26. Chaur, M. N., Melin, F., Ortiz, A. L. & Echegoyen, L. Chemical, electrochemical, and structural properties of endohedral metallofullerenes. Angew. Chem. Int. Ed. 48, 7514–7538 (2009).

    Article  CAS  Google Scholar 

  27. Campanera, J. M., Bo, C. & Poblet, J. M. General rule for the stabilization of fullerene cages encapsulating trimetallic nitride templates. Angew. Chem. Int. Ed. 44, 7230–7233 (2005).

    Article  CAS  Google Scholar 

  28. Valencia, R., Rodriguez-Fortea, A. & Poblet, J. M. Understanding the stabilization of metal carbide endohedral fullerenes M2C2@C82 and related systems. J. Phys. Chem. A 112, 4550–4555 (2008).

    Article  CAS  Google Scholar 

  29. Popov, A. A. & Dunsch, L. Structure, stability, and cluster-cage interactions in nitride clusterfullerenes M3N@C2n (M = Sc, Y; 2n = 68–98): a density functional theory study. J. Am. Chem. Soc. 129, 11835–11849 (2007).

    Article  CAS  Google Scholar 

  30. Raghavachari, K. Ground state of C84: two almost isoenergetic isomers. Chem. Phys. Lett. 190, 397–400 (1992).

    Article  CAS  Google Scholar 

  31. Zettergren, H., Alcamí, M. & Martín, F. Fullerenes containing a uniform distribution of pyrenes and adjacent pentagons. Chem. Phys. Chem. 8, 861–866 (2008).

    Article  Google Scholar 

  32. Morokuma, K. Molecular orbital studies of hydrogen bonds. III. C=O · · · H–O hydrogen bond in H2CO · · · H2O and H2CO · · · 2H2O. J. Chem. Phys. 55, 1236–1244 (1971).

    Article  CAS  Google Scholar 

  33. Poblet, J. M., Lopez, X. & Bo, C. Ab initio and DFT modelling of complex materials: towards the understanding of electronic and magnetic properties of polyoxometalates. Chem. Soc. Rev. 32, 297–308 (2003).

    Article  CAS  Google Scholar 

  34. Fowler, P. W. & Manolopoulos, D. E. An Atlas of Fullerenes (Oxford Univ. Press, 1995).

    Google Scholar 

  35. Mercado, B. Q. et al. Is the isolated pentagon rule merely a suggestion for endohedral fullerenes? The structure of a second egg-shaped endohedral fullerene Gd3N@Cs(39663)-C82 . J. Am. Chem. Soc. 130, 7854–7855 (2008).

    Article  CAS  Google Scholar 

  36. Yang, S. F., Popov, A. A. & Dunsch, L. Violating the isolated pentagon rule (IPR): the endohedral non-IPR C70 cage of Sc3N@C70 . Angew. Chem. Int. Ed. 46, 1256–1259 (2007).

    Article  CAS  Google Scholar 

  37. Kato, H., Taninaka, A., Sugai, T. & Shinohara, H. Structure of a missing-caged metallofullerene: La2@C72 . J. Am. Chem. Soc. 125, 7782–7783 (2003).

    Article  CAS  Google Scholar 

  38. Shi, Z.-Q., Wu, X., Wang, C.-R., Lu, X. & Shinohara, H. Isolation and characterization of Sc2C2@C68: a metal-carbide endofullerene with a non-IPR carbon cage. Angew. Chem. Int. Ed. 45, 2107–2111 (2006).

    Article  CAS  Google Scholar 

  39. Müller, A., Krickemeyer, E., Bogge, H., Schmidtmann, M. & Peters, F. An inorganic super fullerene and Keplerate based on molybdenum oxide. Angew. Chem. Int. Ed. 37, 3359–3363 (1998).

    Article  Google Scholar 

  40. Sigmon, G. E. et al. Symmetry versus minimal pentagonal adjacencies in uranium-based polyoxometalate fullerene topologies. Angew. Chem. Int. Ed. 48, 2737–2740 (2009).

    Article  CAS  Google Scholar 

  41. Becke, A. D. Density-functional exchange-energy approximation with correct asymptotic behavior. Phys. Rev. A 38, 3098–3100 (1988).

    Article  CAS  Google Scholar 

  42. Perdew, J. P. Density-functional approximation for the correlation energy of the inhomogeneous electron gas. Phys. Rev. B 33, 8822–8824 (1986).

    Article  CAS  Google Scholar 

  43. Olmstead, M. M. et al. Isolation and structural characterization of the endohedral fullerene Sc3N@C78 . Angew. Chem. Int. Ed. 40, 1223–1225 (2001).

    Article  CAS  Google Scholar 

  44. Yamada, M., Akasaka, T. & Nagase, S. Endohedral metal atoms in pristine and functionalized fullerene cages. Acc. Chem. Res. 43, 92–102 (2010).

    Article  CAS  Google Scholar 

  45. Cai, T. et al. Structure and enhanced reactivity rates of the D5hSc3N@C80 and Lu3N@C80 metallofullerene isomers: the importance of the pyracylene motif. J. Am. Chem. Soc. 128, 8581–8589 (2006).

    Article  CAS  Google Scholar 

  46. Olmstead, M. M., de Bettencourt-Dias, A., Stevenson, S., Dorn, H. C. & Balch, A. L. Crystallographic characterization of the structure of the endohedral fullerene {Er2@C82 isomer I} with Cs cage symmetry and multiple sites for erbium along a band of ten contiguous hexagons. J. Am. Chem. Soc. 124, 4172–4173 (2002).

    Article  CAS  Google Scholar 

  47. Zuo, T. et al. Isolation and structural characterization of a family of endohedral fullerenes including the large, chiral cage fullerenes Tb3N@C88 and Tb3N@C86 as well as the Ih and D5h isomers of Tb3N@C80 . J. Am. Chem. Soc. 129, 2035–2043 (2007).

    Article  CAS  Google Scholar 

  48. Valencia, R., Rodriguez-Fortea, A. & Poblet, J. M. Large fullerenes stabilized by encapsulation of metallic clusters. Chem. Commun. 4161–4163 (2007).

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Acknowledgements

This work was supported by the Spanish Ministerio de Ciencia e Innovación (CTQ2008-06549-C02-01/BQU and the Ramon y Cajal Program) and by the Generalitat de Catalunya (2009SGR-00462 and XRQTC). We thank S. Alvarez for discussions on icosahedral species.

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Authors and Affiliations

  1. Departament de Química Física i Inorgànica, Universitat Rovira i Virgili C/ Marcel·lí Domingo s/n, Tarragona, 43007, Spain

    Antonio Rodríguez-Fortea, Núria Alegret & Josep M. Poblet

  2. Department of Chemistry, University of California, One Shields Avenue, Davis, 95616, California, USA

    Alan L. Balch

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Contributions

A.R.-F. planned the calculations, developed specific codes to select the structures, charges and data in general, and carried out AM1 and DFT calculations; N.A. carried out DFT calculations; A.L.B. devised the project, discussed the results and co-wrote the paper; J.M.P. coordinated the project, discussed the results and co-wrote the paper.

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Correspondence to Josep M. Poblet.

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Rodríguez-Fortea, A., Alegret, N., Balch, A. et al. The maximum pentagon separation rule provides a guideline for the structures of endohedral metallofullerenes. Nature Chem 2, 955–961 (2010). https://doi.org/10.1038/nchem.837

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