Electrochemistry and Frontier Molecular Orbitals of Endohedral Metallofullerenes

Chapter
Part of the Nanostructure Science and Technology book series (NST)

Abstract

Fullerenes exhibit rich redox activity and are able to accommodate up to 6 surplus electrons or give away 1–2 electrons in solution. EMFs inherit this property from empty fullerenes, and also add a new dimension to the redox behavior because endohedral clusters can exhibit their own redox activity despite their shielding by the carbon cage. This chapter provides a systematic overview of electrochemical properties of different classes of endohedral metallofullerenes. In particular, the balance between fullerene- and cluster-based redox activity in complex endohedral metallofullerenes is discussed using frontier molecular orbitals as a guide.

Keywords

Redox Potential HOMOHighest Occupy Molecular Orbital LUMOLowest Unoccupied Molecular Orbital Oxidation Potential Redox Activity 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

References

  1. 1.
    Suzuki T, Maruyama Y, Kato T et al (1993) Electrochemical properties of La@C82. J Am Chem Soc 115(23):11006–11007CrossRefGoogle Scholar
  2. 2.
    Suzuki T, Maruyama Y, Kato T et al (1995) Electrochemical properties of fullerenolanthanides. Synth Met 70(1–3):1443–1446CrossRefGoogle Scholar
  3. 3.
    Suzuki T, Kikuchi K, Oguri F et al (1996) Electrochemical properties of fullerenolanthanides. Tetrahedron 52(14):4973–4982CrossRefGoogle Scholar
  4. 4.
    Suzuki T, Maruyama Y, Kato T et al (1995) Electrochemistry and Ab-Initio study of the dimetallofullerene La2@C80. Angew Chem-Int Edit Engl 34(10):1094–1096CrossRefGoogle Scholar
  5. 5.
    Kikuchi K, Nakao Y, Suzuki S et al (1994) Characterization of the isolated Y@C82. J Am Chem Soc 116(20):9367–9368CrossRefGoogle Scholar
  6. 6.
    Xie QS, Perezcordero E, Echegoyen L (1992) Electrochemical detection of C606- and C706-—enhanced stability of fullerides in solution. J Am Chem Soc 114(10):3978–3980CrossRefGoogle Scholar
  7. 7.
    Reed CA, Bolskar RD (2000) Discrete fulleride anions and fullerenium cations. Chem Rev 100(3):1075–1119CrossRefGoogle Scholar
  8. 8.
    Zalibera M, Rapta P, Popov AA et al (2009) Charged states of four isomers of C84 fullerene: In Situ ESR and Vis-’NIR Spectroelectrochemistry and DFT Calculations. J Phys Chem C 113(13):5141–5149Google Scholar
  9. 9.
    Zalibera M, Popov AA, Kalbac M et al (2008) The extended view on the empty C 2(3)-C82 fullerene: isolation, spectroscopic, electrochemical, and spectroelectrochemical characterization and DFT calculations. Chem-Eur J 14(32):9960–9967CrossRefGoogle Scholar
  10. 10.
    Gao XA, Van Caemelbecke E, Kadish KM (1998) Visible and near-infrared absorption spectra of singly and doubly reduced C76 fullerene anions. Electrochem Solid State Lett 1(5):222–223CrossRefGoogle Scholar
  11. 11.
    Xie QS, Arias F, Echegoyen L (1993) Electrochemically-reversible, single-electron oxidation of C60 and C70. J Am Chem Soc 115(21):9818–9819CrossRefGoogle Scholar
  12. 12.
    Dubois D, Kadish KM, Flanagan S et al (1991) Electrochemical detection of fulleronium and highly reduced fulleride C60 5- Ions in solution. J Am Chem Soc 113(20):7773–7774CrossRefGoogle Scholar
  13. 13.
    Bruno C, Doubitski I, Marcaccio M et al (2003) Electrochemical generation of C60 2+ and C60 3+. J Am Chem Soc 125(51):15738–15739CrossRefGoogle Scholar
  14. 14.
    Webster RD, Heath GA (2001) Voltammetric, EPR and UV-VIS-NIR spectroscopic studies associated with the one-electron oxidation of C60 and C70 in 1,1′,2,2′-tetrachloroethane containing trifluoromethanesulfonic acid. Phys Chem Chem Phys 3(13):2588–2594CrossRefGoogle Scholar
  15. 15.
    Yang YF, Arias F, Echegoyen L et al (1995) Reversible fullerene electrochemistry—correlation with the Homo-Lumo energy difference for C60, C70, C76, C78, and C84. J Am Chem Soc 117(29):7801–7804CrossRefGoogle Scholar
  16. 16.
    Okada H, Komuro T, Sakai T et al (2012) Preparation of endohedral fullerene containing lithium (Li@C60) and isolation as pure hexafluorophosphate salt ([Li+@C60][PF6 ]). RSC Adv 2(28):10624–10631CrossRefGoogle Scholar
  17. 17.
    Popov AA, Dunsch L (2011) Electrochemistry in Cavea: endohedral redox reactions of encaged species in fullerenes. J Phys Chem Lett 2(7):786–794CrossRefGoogle Scholar
  18. 18.
    Zhang Y, Popov AA (2014) Transition-metal and rare-earth-metal redox couples inside carbon cages: fullerenes acting as innocent ligands. Organometallics 33(18):4537–4549CrossRefGoogle Scholar
  19. 19.
    Aoyagi S, Nishibori E, Sawa H et al (2010) A layered ionic crystal of polar Li@C60 superatoms. Nat Chem 2(8):678–683CrossRefGoogle Scholar
  20. 20.
    Liu J, Shi Z, Gu Z (2009) The cage and metal effect: spectroscopy and electrochemical survey of a series of Sm-containing high metallofullerenes. Chem-Asian J 4(11):1703–1711CrossRefGoogle Scholar
  21. 21.
    Lu X, Slanina Z, Akasaka T et al (2010) Yb@C2n (n = 40, 41, 42): new fullerene allotropes with unexplored electrochemical properties. J Am Chem Soc 132(16):5896–5905CrossRefGoogle Scholar
  22. 22.
    Xu JX, Li MX, Shi ZJ et al (2005) Electrochemical survey: the effect of the cage size and structure on the electronic structures of a series of ytterbium metallofullerenes. Chem-Eur J 12(2):562–567CrossRefGoogle Scholar
  23. 23.
    Zhang Y, Xu JX, Hao C et al (2006) Synthesis, isolation, spectroscopic and electrochemical characterization of some calcium-containing metallofullerenes. Carbon 44(3):475–479CrossRefGoogle Scholar
  24. 24.
    Sun BY, Li MX, Luo HX et al (2002) Electrochemical properties of metallofullerenes and their anions. Electrochim Acta 47(21):3545–3549CrossRefGoogle Scholar
  25. 25.
    Kuran P, Krause M, Bartl A et al (1998) Preparation, isolation and characterisation of Eu@C74: the first isolated europium endohedral fullerene. Chem Phys Lett 292(4–6):580–586CrossRefGoogle Scholar
  26. 26.
    Hu Z, Hao Y, Slanina Z et al (2015) Popular C82 fullerene cage encapsulating a divalent metal ion Sm2+: structure and electrochemistry. Inorg Chem 54(5):2103–2108CrossRefGoogle Scholar
  27. 27.
    Xu W, Niu B, Feng L et al (2012) Access to an unexplored chiral C82 cage by encaging a divalent metal: structural elucidation and electrochemical studies of Sm@C 2(5)-C82. Chem-Eur J 18(45):14246–14249CrossRefGoogle Scholar
  28. 28.
    Hao Y, Feng L, Xu W et al (2015) Sm@C2v(19138)-C76: a non-IPR cage stabilized by a divalent metal ion. Inorg Chem 54(9):4243–4248CrossRefGoogle Scholar
  29. 29.
    Liu F, Wang S, Guan J et al (2014) Putting a terbium-monometallic cyanide cluster into the C82 fullerene cage: TbCN@C 2(5)-C82. Inorg Chem 53(10):5201–5205CrossRefGoogle Scholar
  30. 30.
    Yang S, Chen C, Liu F et al (2013) An improbable monometallic cluster entrapped in a popular fullerene cage: YCN@C s(6)-C82. Sci Rep 3:1487CrossRefGoogle Scholar
  31. 31.
    Liu F, Gao C-L, Deng Q et al (2016) Triangular monometallic cyanide cluster entrapped in carbon cage with geometry-dependent molecular magnetism. J Am Chem Soc 138(44):14764–14771CrossRefGoogle Scholar
  32. 32.
    Wang W, Ding J, Yang S et al (1997) Electrochemical properties of 4f-block metallofullerenes. In: Kadish KM, Ruoff RS (eds) Fullerenes. Recent advances in the chemistry and physics of fullerenes and related materials, vol 4. Electrochemical society, Pennington, pp 417–428Google Scholar
  33. 33.
    Yamada M, Feng L, Wakahara T et al (2005) Synthesis and characterization of exohedrally silylated M@C82 (M = Y and La). J Phys Chem B 109(13):6049–6051CrossRefGoogle Scholar
  34. 34.
    Maeda Y, Matsunaga Y, Wakahara T et al (2004) Isolation and characterization of a carbene derivative of La@C82. J Am Chem Soc 126(22):6858–6859CrossRefGoogle Scholar
  35. 35.
    Feng L, Wakahara T, Nakahodo T et al (2006) The bingel monoadducts of La@C82: synthesis, characterization, and electrochemistry. Chem-Eur J 12(21):5578–5586CrossRefGoogle Scholar
  36. 36.
    Takano Y, Yomogida A, Nikawa H et al (2008) Radical coupling reaction of paramagnetic endohedral metallofullerene La@C82. J Am Chem Soc 130(48):16224–16230CrossRefGoogle Scholar
  37. 37.
    Popov AA, Yang S, Dunsch L (2013) Endohedral fullerenes. Chem Rev 113(8):5989–6113CrossRefGoogle Scholar
  38. 38.
    Yamamoto K (1999) Electrochemical study on electronic structure of mono-lanthanofullerenes of La@Cn (n = 82, 86, and 90). In: Kamat PV, Guldi D, Kadish KM (eds) Fullerenes. Recent advances in the chemistry and physics of fullerenes and related materials, vol 7. Electrochemical Society, Pennington, pp 761–770Google Scholar
  39. 39.
    Popov AA, Avdoshenko SM, Pendás AM et al (2012) Bonding between strongly repulsive metal atoms: an oxymoron made real in a confined space of endohedral metallofullerenes. Chem Commun 48:8031–8050CrossRefGoogle Scholar
  40. 40.
    Lu X, Nikawa H, Nakahodo T et al (2008) Chemical understanding of a Non-IPR metallofullerene: stabilization of encaged metals on fused-pentagon bonds in La2@C72. J Am Chem Soc 130:9129–9136CrossRefGoogle Scholar
  41. 41.
    Cao BP, Wakahara T, Tsuchiya T et al (2004) Isolation, characterization, and theoretical study of La2@C78. J Am Chem Soc 126(30):9164–9165CrossRefGoogle Scholar
  42. 42.
    Yamada M, Mizorogi N, Tsuchiya T et al (2009) Synthesis and characterization of the D 5h isomer of the endohedral dimetallofullerene Ce2@C80: two-dimensional circulation of encapsulated metal atoms inside a fullerene cage. Chem-Eur J 15:9486–9493CrossRefGoogle Scholar
  43. 43.
    Yamada M, Wakahara T, Tsuchiya T et al (2008) Spectroscopic and theoretical study of endohedral dimetallofullerene having a Non-IPR fullerene cage: Ce2@C72. J Phys Chem A 112:7627–7631CrossRefGoogle Scholar
  44. 44.
    Yamada M, Wakahara T, Tsuchiya T et al (2008) Location of the metal atoms in Ce2@C78 and its bis-silylated derivative. Chem Commun 558–560Google Scholar
  45. 45.
    Yamada M, Nakahodo T, Wakahara T et al (2005) Positional control of encapsulated atoms inside a fullerene cage by exohedral addition. J Am Chem Soc 127(42):14570–14571CrossRefGoogle Scholar
  46. 46.
    Suzuki M, Mizorogi N, Yang T et al (2013) La2@C s(17490)-C76: a new non-IPR dimetallic metallofullerene featuring unexpectedly weak metal-pentalene interactions. Chem-Eur J 19(50):17125–17130CrossRefGoogle Scholar
  47. 47.
    Fu W, Zhang J, Fuhrer T et al (2011) Gd2@C79N: isolation, characterization, and monoadduct formation of a very stable heterofullerene with a magnetic spin state of S = 15/2. J Am Chem Soc 133:9741–9750CrossRefGoogle Scholar
  48. 48.
    Kato T (2007) Metal dimer and trimer within spherical carbon cage. J Mol Struct 838(1–3):84–88CrossRefGoogle Scholar
  49. 49.
    Zuo T, Xu L, Beavers CM et al (2008) M2@C79N (M = Y, Tb): isolation and characterization of stable endohedral metallofullerenes exhibiting M…M bonding interactions inside Aza[80]fullerene cages. J Am Chem Soc 130(39):12992–12997CrossRefGoogle Scholar
  50. 50.
    Kurihara H, Lu X, Iiduka Y et al (2012) Sc2@C 3v(8)-C82 vs. Sc2C2@C 3v(8)-C82: drastic effect of C2 capture on the redox properties of scandium metallofullerenes. Chem Commun 48:1290–1292CrossRefGoogle Scholar
  51. 51.
    Iiduka Y, Wakahara T, Nakajima K et al (2007) Experimental and theoretical studies of the scandium carbide endohedral metallofullerene Sc2C2@C82 and its carbene derivative. Angew Chem-Int Edit 46(29):5562–5564CrossRefGoogle Scholar
  52. 52.
    Tang Q, Abella L, Hao Y et al (2016) Sc2O@C 3v(8)-C82: a missing isomer of Sc2O@C82. Inorg Chem 55(4):1926–1933CrossRefGoogle Scholar
  53. 53.
    Mercado BQ, Chen N, Rodriguez-Fortea A et al (2011) The shape of the Sc22-S) unit trapped in C82: crystallographic, computational, and electrochemical studies of the isomers, Sc22-S)@C s(6)-C82 and Sc22-S)@C 3v(8)-C82. J Am Chem Soc 133(17):6752–6760CrossRefGoogle Scholar
  54. 54.
    Zhang M, Hao Y, Li X et al (2014) Facile synthesis of an extensive family of Sc2O@C2n (n = 35-47) and chemical insight into the smallest member of Sc2O@C2(7892)-C70. J Phys Chem C 118(49):28883–28889CrossRefGoogle Scholar
  55. 55.
    Chen N, Mulet-Gas M, Li Y-Y et al (2013) Sc2S@C 2(7892)-C70: a metallic sulfide cluster inside a non-IPR C70 cage. Chem Sci 4(1):180–186CrossRefGoogle Scholar
  56. 56.
    Feng Y, Wang T, Wu J et al (2013) Structural and electronic studies of metal carbide clusterfullerene Sc2C2@C s-C72. Nanoscale 5(15):6704–6707CrossRefGoogle Scholar
  57. 57.
    Chen N, Beavers CM, Mulet-Gas M et al (2012) Sc2S@C s(10528)-C72: a dimetallic sulfide endohedral fullerene with a Non-IPR cage. J Am Chem Soc 134(18):7851–7860CrossRefGoogle Scholar
  58. 58.
    Yang T, Hao Y, Abella L et al (2015) Sc2O@T d(19151)-C76: hindered cluster motion inside a tetrahedral carbon cage probed by crystallographic and computational studies. Chem-Eur J 21(31):11110–11117CrossRefGoogle Scholar
  59. 59.
    Kurihara H, Lu X, Iiduka Y et al (2011) Sc2C2@C80 rather than Sc2@C82: templated formation of unexpected C 2v(5)-C80 and temperature-dependent dynamic motion of internal Sc2C2 cluster. J Am Chem Soc 133(8):2382–2385CrossRefGoogle Scholar
  60. 60.
    Tang Q, Abella L, Hao Y et al (2015) Sc2O@C 2v(5)-C80: dimetallic oxide cluster inside a C80 fullerene cage. Inorg Chem 54(20):9845–9852CrossRefGoogle Scholar
  61. 61.
    Samoylova NA, Avdoshenko SM, Krylov DS et al (2017) Confining the spin between two metal atoms within the carbon cage: Redox-active metal-metal bonds in dimetallofullerenes and their stable cation radicals. Nanoscale doi:  10.1039/C7NR02288C
  62. 62.
    Lu X, Nakajima K, Iiduka Y et al (2011) Structural elucidation and regioselective functionalization of an unexplored carbide cluster metallofullerene Sc2C2@C s(6)-C82. J Am Chem Soc 133(48):19553–19558CrossRefGoogle Scholar
  63. 63.
    Lu X, Nakajima K, Iiduka Y et al (2012) The long-believed Sc2@C 2v(17)-C84 is actually Sc2C2@C 2v(9)-C82: unambiguous structure assignment and chemical functionalization. Angew Chem-Int Edit Engl 51(24):5889–5892CrossRefGoogle Scholar
  64. 64.
    Chen C-H, Ghiassi KB, Cerón MR et al (2015) Beyond the butterfly: Sc2C2@C 2v(9)-C86, an endohedral fullerene containing a planar, twisted Sc2C2 unit with remarkable crystalline order in an unprecedented carbon cage. J Am Chem Soc 137(32):10116–10119CrossRefGoogle Scholar
  65. 65.
    Popov AA, Dunsch L (2008) Hindered cluster rotation and 45Sc hyperfine splitting constant in distonoid anion radical Sc3N@C80, and spatial spin charge separation as a general principle for anions of endohedral fullerenes with metal-localized lowest unoccupied molecular orbitals. J Am Chem Soc 130(52):17726–17742CrossRefGoogle Scholar
  66. 66.
    Jakes P, Dinse KP (2001) Chemically induced spin transfer to an encased molecular cluster: an EPR study of Sc3N@C80 radical anions. J Am Chem Soc 123(36):8854–8855CrossRefGoogle Scholar
  67. 67.
    Yang SF, Zalibera M, Rapta P et al (2006) Charge-induced reversible rearrangement of endohedral fullerenes: electrochemistry of tridysprosium nitride clusterfullerenes Dy3N@C2n (2n = 78, 80). Chem-Eur J 12(30):7848–7855CrossRefGoogle Scholar
  68. 68.
    Tarabek J, Yang S, Dunsch L (2009) Redox properties of mixed lutetium/yttrium nitride clusterfullerenes: endohedral LuxY3-xN@C80(I) (x = 0-3) compounds. Chem Phys Chem 10(7):1037–1043CrossRefGoogle Scholar
  69. 69.
    Elliott B, Yu L, Echegoyen L (2005) A simple isomeric separation of D 5h and I h Sc3N@C80 by selective chemical oxidation. J Am Chem Soc 127(31):10885–10888CrossRefGoogle Scholar
  70. 70.
    Chaur MN, Athans AJ, Echegoyen L (2008) Metallic nitride endohedral fullerenes: synthesis and electrochemical properties. Tetrahedron 64(50):11387–11393CrossRefGoogle Scholar
  71. 71.
    Rapta P, Popov AA, Yang SF et al (2008) The charged states of Sc3N@C68: an in situ spectroelectrochemical study of the radical cation and radical anion of a Non-IPR fullerene. J Phys Chem A 112:5858–5865CrossRefGoogle Scholar
  72. 72.
    Popov AA, Avdoshenko SM, Cuniberti G et al (2011) Dimerization of radical-anions: nitride clusterfullerenes versus empty fullerenes. J Phys Chem Lett 1592–1600Google Scholar
  73. 73.
    Konarev DV, Zorina LV, Khasanov SS et al (2016) A crystalline anionic complex of scandium nitride endometallofullerene: experimental observation of single-bonded (Sc3N@I h-C80 )2 dimers. Chem Commun 52:10763–10766CrossRefGoogle Scholar
  74. 74.
    Yang SF, Rapta P, Dunsch L (2007) The spin state of a charged non-IPR fullerene: the stable radical cation of Sc3N@C68. Chem Commun 2:189–191CrossRefGoogle Scholar
  75. 75.
    Chaur MN, Aparicio-Angles X, Mercado BQ et al (2010) Structural and electrochemical property correlations of metallic nitride endohedral metallofullerenes. J Phys Chem C 114(30):13003–13009CrossRefGoogle Scholar
  76. 76.
    Cai T, Xu LS, Anderson MR et al (2006) Structure and enhanced reactivity rates of the D 5h Sc3N@C80 and Lu3N@C80 metallofullerene isomers: the importance of the pyracylene motif. J Am Chem Soc 128(26):8581–8589CrossRefGoogle Scholar
  77. 77.
    Wei T, Wang S, Liu F et al (2015) Capturing the long-sought small-bandgap endohedral fullerene Sc3N@C82 with low kinetic stability. J Am Chem Soc 137(8):3119–3123CrossRefGoogle Scholar
  78. 78.
    Beavers CM, Chaur MN, Olmstead MM et al (2009) Large metal ions in a relatively small fullerene cage: the structure of Gd3N@C 2(22010)-C78 departs from the isolated pentagon rule. J Am Chem Soc 131(32):11519–11524CrossRefGoogle Scholar
  79. 79.
    Chaur MN, Melin F, Elliott B et al (2007) Gd3N@C2n (n = 40, 42, and 44): remarkably low HOMO-LUMO gap and unusual electrochemical reversibility of Gd3N@C88. J Am Chem Soc 129(47):14826–14829CrossRefGoogle Scholar
  80. 80.
    Fu W, Zhang J, Champion H et al (2011) Electronic properties and 13C NMR structural study of Y3N@C88. Inorg Chem 50(10):4256–4259CrossRefGoogle Scholar
  81. 81.
    Chaur MN, Melin F, Elliott B et al (2008) New M3N@C2n endohedral metallofullerene families (M = Nd, Pr, Ce; n = 40-53): expanding the preferential templating of the C88 cage and approaching the C96 cage. Chem-Eur J 14(15):4594–4599CrossRefGoogle Scholar
  82. 82.
    Chaur MN, Valencia R, Rodriguez-Fortea A et al (2009) Trimetallic nitride endohedral fullerenes: experimental and theoretical evidence for the M3N6+@C2n6- model. Angew Chem-Int Edit 48(8):1425–1428CrossRefGoogle Scholar
  83. 83.
    Chaur MN, Melin F, Ashby J et al (2008) Lanthanum nitride endohedral fullerenes La3N@C2n (43 < n < 55): preferential formation of La3N@C96. Chem-Eur J 14(27):8213–8219CrossRefGoogle Scholar
  84. 84.
    Cardona CM, Elliott B, Echegoyen L (2006) Unexpected chemical and electrochemical properties of M3N@C80 (M = Sc, Y, Er). J Am Chem Soc 128(19):6480–6485CrossRefGoogle Scholar
  85. 85.
    Li F-F, Pinzon JR, Mercado BQ et al (2011) [2 + 2] cycloaddition reaction to Sc3N@I h-C80. The formation of very stable [5,6]- and [6,6]-adducts. J Am Chem Soc 133(5):1563–1571CrossRefGoogle Scholar
  86. 86.
    Pinzon JR, Zuo TM, Echegoyen L (2010) Synthesis and electrochemical studies of bingel-hirsch derivatives of M3N@I h-C80 (M = Sc, Lu). Chem-Eur J 16(16):4864–4869CrossRefGoogle Scholar
  87. 87.
    Li F-F, Rodríguez-Fortea A, Peng P et al (2012) Electrosynthesis of a Sc3N@I h-C80 methano derivative from trianionic Sc3N@I h-C80. J Am Chem Soc 134(17):7480–7487CrossRefGoogle Scholar
  88. 88.
    Feng L, Gayathri Radhakrishnan S, Mizorogi N et al (2011) Synthesis and charge-transfer chemistry of La2@I h-C80/Sc3N@I h-C80-Zinc porphyrin conjugates: impact of endohedral cluster. J Am Chem Soc 133(19):7608–7618CrossRefGoogle Scholar
  89. 89.
    Wakahara T, Iiduka Y, Ikenaga O et al (2006) Characterization of the bis-silylated endofullerene Sc3N@C80. J Am Chem Soc 128(30):9919–9925CrossRefGoogle Scholar
  90. 90.
    Popov AA, Shustova NB, Svitova AL et al (2010) Redox-tuning endohedral fullerene spin states: from the dication to the trianion radical of Sc3N@C80(CF3)2 in five reversible single-electron steps. Chem-Eur J 16(16):4721–4724CrossRefGoogle Scholar
  91. 91.
    Shustova NB, Peryshkov DV, Kuvychko IV et al (2011) Poly(perfluoroalkylation) of metallic nitride fullerenes reveals addition-pattern guidelines: synthesis and characterization of a family of Sc3N@C80(CF3)n (n = 2-16) and their radical anions. J Am Chem Soc 133(8):2672–2690CrossRefGoogle Scholar
  92. 92.
    Piro NA, Robinson JR, Schelter EJ (2014) The electrochemical behavior of cerium(III/IV) complexes: thermodynamics, kinetics and applications in synthesis. Coord Chem Rev 260:21–36CrossRefGoogle Scholar
  93. 93.
    Vargová A, Popov A, Rapta P et al (2010) Electrochemical tuning of spin states of the endohedral metallofullerene Y@C82 as probed by ESR spectroelectrochemistry. Chem Phys Chem 11(8):1650–1653CrossRefGoogle Scholar
  94. 94.
    Zhang Y, Schiemenz S, Popov AA et al (2013) Strain-driven endohedral redox couple CeIV/CeIII in nitride clusterfullerenes CeM2N@C80 (M = Sc, Y, Lu). J Phys Chem Lett 4:2404–2409CrossRefGoogle Scholar
  95. 95.
    Zhang Y, Popov AA, Dunsch L (2014) Endohedral metal or a fullerene cage based oxidation? Redox duality of nitride clusterfullerenes CexM3-xN@C78-88 (x = 1, 2; M = Sc and Y) dictated by the encaged metals and the carbon cage size. Nanoscale 6:1038–1048CrossRefGoogle Scholar
  96. 96.
    Chen C, Liu F, Li S et al (2012) Titanium/yttrium mixed metal nitride clusterfullerene TiY2N@C80: synthesis, isolation, and effect of the group-III metal. Inorg Chem 51(5):3039–3045CrossRefGoogle Scholar
  97. 97.
    Yang S, Chen C, Popov A et al (2009) An endohedral titanium(III) in a clusterfullerene: putting a non-group-III metal nitride into the C80-I h fullerene cage. Chem Commun 6391–6393Google Scholar
  98. 98.
    Wei T, Wang S, Lu X et al (2016) Entrapping a group-VB transition metal, vanadium, within an endohedral metallofullerene: VxSc3–xN@I h-C80 (x = 1, 2). J Am Chem Soc 138(1):207–214CrossRefGoogle Scholar
  99. 99.
    Popov AA, Chen C, Yang S et al (2010) Spin-flow vibrational spectroscopy of molecules with flexible spin density: electrochemistry, ESR, cluster and spin dynamics, and bonding in TiSc2N@C80. ACS Nano 4(8):4857–4871CrossRefGoogle Scholar
  100. 100.
    Junghans K, Rosenkranz M, Popov AA (2016) Sc3CH@C80: selective 13C enrichment of the central carbon atom. Chem Commun 52:6561–6564CrossRefGoogle Scholar
  101. 101.
    Popov AA, Chen N, Pinzón JR et al (2012) Redox-active scandium oxide cluster inside a fullerene cage: spectroscopic, voltammetric, electron spin resonance spectroelectrochemical, and extended density functional theory study of Sc4O2@C80 and its ion radicals. J Am Chem Soc 134(48):19607–19618CrossRefGoogle Scholar
  102. 102.
    Wang T-S, Feng L, Wu J-Y et al (2010) Planar quinary cluster inside a fullerene cage: synthesis and structural characterizations of Sc3NC@C80-I h. J Am Chem Soc 132(46):16362–16364CrossRefGoogle Scholar
  103. 103.
    Feng Y, Wang T, Wu J et al (2014) Electron-spin excitation by implanting hydrogen into metallofullerene: the synthesis and spectroscopic characterization of Sc4C2H@I h-C80. Chem Commun 50(81):12166–12168CrossRefGoogle Scholar
  104. 104.
    Elliott B, Pykhova AD, Rivera J et al (2013) Spin density and cluster dynamics in Sc3N@C80 upon [5,6] exohedral functionalization: an ESR and DFT study. J Phys Chem C 117(5):2344–2348CrossRefGoogle Scholar
  105. 105.
    Svitova AL, Ghiassi K, Schlesier C et al (2014) Endohedral fullerene with μ3-carbido ligand and titanium-carbon double bond stabilized inside a carbon cage. Nat Commun 5:3568. doi:3510.1038/ncomms4568Google Scholar
  106. 106.
    Junghans K, Ghiassi KB, Samoylova NA et al (2016) Synthesis and isolation of the titanium-scandium endohedral fullerenes—Sc2TiC@I h-C80, Sc2TiC@D 5h-C80, and Sc2TiC2@I h-C80: metal size tuning of the TiIV/TiIII redox potentials. Chem-Eur J 22(37):13098–13107CrossRefGoogle Scholar
  107. 107.
    Junghans K, Schlesier C, Kostanyan A et al (2015) Methane as a selectivity booster in the arc-discharge synthesis of endohedral fullerenes: selective synthesis of the single-molecule magnet Dy2TiC@C80 and its congener Dy2TiC2@C80. Angew Chem-Int Edit Engl 54(45):13411–13415CrossRefGoogle Scholar
  108. 108.
    Xu W, Feng L, Calvaresi M et al (2013) An experimentally observed trimetallofullerene Sm3@I h-C80: encapsulation of three metal atoms in a cage without a nonmetallic mediator. J Am Chem Soc 135(11):4187–4190CrossRefGoogle Scholar
  109. 109.
    Wakahara T, Sakuraba A, Iiduka Y et al (2004) Chemical reactivity and redox property of Sc3@C82. Chem Phys Lett 398:553–556CrossRefGoogle Scholar
  110. 110.
    Zhang L, Popov AA, Yang S et al (2010) An endohedral redox system in a fullerene cage: the Ce based mixed cluster fullerene Lu2CeN@C80. Phys Chem Chem Phys 12:7840–7847CrossRefGoogle Scholar

Copyright information

© Springer International Publishing AG 2017

Authors and Affiliations

  1. 1.Leibniz Institute for Solid State and Materials ResearchDresdenGermany

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