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Fulleride

January 21, 2023

Fullerides are chemical compounds containing fullerene anions. Common fullerides are derivatives of the most common fullerenes, i.e. C60 and C70. The scope of the area is large because multiple charges are possible, i.e., [C60]n− (n = 1, 2...6), and all fullerenes can be converted to fullerides. The suffix "-ide" implies their negatively charged nature.

Cs3C60 crystal structure

Fullerides can be isolated as derivatives with a wide range of cations. Most heavily studied derivatives are those with alkali metals, but fullerides have been prepared with organic cations. Fullerides are typically dark colored solids that generally dissolve in polar organic solvents.

Structure and bonding

According to electronic structure calculations, the LUMO of C60 is a triply degenerate orbital of t1u symmetry. Using the technique cyclic voltammetry, C60 can be shown to undergo six reversible reductions starting at −1 V referenced to the Fc+/Fc couple. Reduction causes only subtle changes in the structure and many derivatives exhibit disorder, which obscures these effects. Many fullerides are subject to Jahn–Teller distortion. In certain cases, e.g. [PPN]2C60, the structures are highly ordered and slight (10 pm) elongation of some C−C bonds is observed.[1]

Preparation

Fullerides have been prepared in various ways:

  • treating with alkali metals to give the alkali metal fullerides:
C60 + 2 K → K2C60
  • treating with suitable organic and organometallic reducing agents, such as cobaltocene and tetrakisdimethylaminoethylene.
  • alkali metal fullerides can be subjected to cation metathesis. In this way the (bis(triphenylphosphine)iminium (PPN+) salts have been prepared, e.g. [PPN]2C60:[1]
K2C60 + 2 [PPN]Cl → [PPN]2C60 + 2 KCl

The fulleride salt ([K(crypt-222)]+)2[C60]2− salt is synthesized by treating C60 with metallic potassium in the presence of [2.2.2]cryptand.

Alkali metal derivatives

Critical temperatures (Tc) of the fulleride salts
M3C60 Tc (K)
Na3C60 (non-superconducting)
K3C60 18
Rb3C60 28
Cs3C60 40

Particular attention has been paid to alkali metal (Na+, K+, Rb+, Cs+) derivatives of C603− because these compounds exhibit physical properties resulting from intercluster interactions such as metallic behavior. In contrast, in C60, the individual molecules interact only weakly, i.e. with essentially nonoverlapping bands. These alkali metal derivatives are sometimes viewed as arising by intercalation of the metal into C60 lattice. Alternatively, these materials are viewed as n-doped fullerenes.[2]

Alkali metal salts of this trianion are superconducting. In M3C60 (M = Na, K, Rb), the M+ ions occupy the interstitial holes in a lattice composed of ccp lattice composed of nearly spherical C60 anions. In Cs3C60, the cages are arranged in a bcc lattice.

In 1991, it was revealed that potassium-doped C60 becomes superconducting at 18 K (−255 °C).[3] This was the highest transition temperature for a molecular superconductor. Since then, superconductivity has been reported in fullerene doped with various other alkali metals.[4][5] It has been shown that the superconducting transition temperature in alkaline-metal-doped fullerene increases with the unit-cell volume V.[6][7] As Cs+ is the largest alkali ion, caesium-doped fullerene is an important material in this family. Superconductivity at 38 K (−235 °C) has been reported in bulk Cs3C60,[8] but only under applied pressure. The highest superconducting transition temperature of 33 K (−240 °C) at ambient pressure is reported for Cs2RbC60.[9]

The increase of transition temperature with the unit-cell volume had been believed to be evidence for the BCS mechanism of C60 solid superconductivity, because inter C60 separation can be related to an increase in the density of states on the Fermi level, N(εF). Therefore, efforts have been made to increase the interfullerene separation, in particular, intercalating neutral molecules into the A3C60 lattice to increase the interfullerene spacing while the valence of C60 is kept unchanged. However, this ammoniation technique has revealed a new aspect of fullerene intercalation compounds: the Mott transition and the correlation between the orientation/orbital order of C60 molecules and the magnetic structure.[10]

Fourfold-reduced materials, i.e., those with the stoichiometry A4C60, are insulating, even though the t1u band is only partially filled.[11] This apparent anomaly may be explained by the Jahn–Teller effect, where spontaneous deformations of high-symmetry molecules induce the splitting of degenerate levels to gain the electronic energy. The Jahn–Teller type electron-phonon interaction is strong enough in C60 solids to destroy the band picture for particular valence states.[10]

A narrow band or strongly correlated electronic system and degenerated ground states are relevant to explaining superconductivity in fulleride solids. When the interelectron repulsion U is greater than the bandwidth, an insulating localized electron ground state is produced in the simple Mott–Hubbard model. This explains the absence of superconductivity at ambient pressure in caesium-doped C60 solids.[8] Electron-correlation-driven localization of the t1u electrons exceeds the critical value, leading to the Mott insulator. The application of high pressure decreases the interfullerene spacing, therefore caesium-doped C60 solids turn to metallic and superconducting.

A fully developed theory of C60 solids superconductivity is lacking, but it has been widely accepted that strong electronic correlations and the Jahn–Teller electron–phonon coupling[12] produce local electron pairings that show a high transition temperature close to the insulator–metal transition.[13]

References

  1. ^ a b Reed, Christopher A.; Bolskar, Robert D. (2000). "Discrete Fulleride Anions and Fullerenium Cations" (PDF). Chemical Reviews. 100 (3): 1075–1120. doi:10.1021/cr980017o.{{cite journal}}: CS1 maint: uses authors parameter (link)
  2. ^ Gunnarsson, O. (1997). "Superconductivity in fullerides". Reviews of Modern Physics. 69 (2): 575–606. arXiv:cond-mat/9611150. Bibcode:1997RvMP...69..575G. doi:10.1103/RevModPhys.69.575.
  3. ^ Hebard, A. F.; Rosseinsky, M. J.; Haddon, R. C.; Murphy, D. W.; Glarum, S. H.; Palstra, T. T. M.; Ramirez, A. P.; Kortan, A. R. (1991). "Superconductivity at 18 K in potassium-doped C60" (PDF). Nature. 350 (6319): 600–601. Bibcode:1991Natur.350..600H. doi:10.1038/350600a0. hdl:11370/3709b8a7-6fc1-4b32-8842-ce9b5355b5e4.
  4. ^ Rosseinsky, M.; Ramirez, A.; Glarum, S.; Murphy, D.; Haddon, R.; Hebard, A.; Palstra, T.; Kortan, A.; Zahurak, S.; Makhija, A. (1991). "Superconductivity at 28 K in RbxC60" (PDF). Physical Review Letters. 66 (21): 2830–2832. Bibcode:1991PhRvL..66.2830R. doi:10.1103/PhysRevLett.66.2830. PMID 10043627.
  5. ^ Chen, C.-C.; Kelty, S. P.; Lieber, C. M. (1991). "(RbxK1−x)3C60 Superconductors: Formation of a Continuous Series of Solid Solutions". Science. 253 (5022): 886–8. Bibcode:1991Sci...253..886C. doi:10.1126/science.253.5022.886. PMID 17751824.
  6. ^ Zhou, O.; Zhu, Q.; Fischer, J. E.; Coustel, N.; Vaughan, G. B. M.; Heiney, P. A.; McCauley, J. P.; Smith, A. B. (1992). "Compressibility of M3C60 Fullerene Superconductors: Relation Between Tc and Lattice Parameter". Science. 255 (5046): 833–5. Bibcode:1992Sci...255..833Z. doi:10.1126/science.255.5046.833. PMID 17756430.
  7. ^ Brown, Craig; Takenobu, Taishi; Kordatos, Konstantinos; Prassides, Kosmas; Iwasa, Yoshihiro; Tanigaki, Katsumi (1999). "Pressure dependence of superconductivity in the Na2Rb0.5Cs0.5C60 fulleride". Physical Review B. 59 (6): 4439–4444. Bibcode:1999PhRvB..59.4439B. doi:10.1103/PhysRevB.59.4439.
  8. ^ a b Ganin, Alexey Y.; Takabayashi, Yasuhiro; Khimyak, Yaroslav Z.; Margadonna, Serena; Tamai, Anna; Rosseinsky, Matthew J.; Prassides, Kosmas (2008). "Bulk superconductivity at 38 K in a molecular system". Nature Materials. 7 (5): 367–71. Bibcode:2008NatMa...7..367G. doi:10.1038/nmat2179. PMID 18425134.
  9. ^ Tanigaki, K.; Ebbesen, T. W.; Saito, S.; Mizuki, J.; Tsai, J. S.; Kubo, Y.; Kuroshima, S. (1991). "Superconductivity at 33 K in CsxRbyC60". Nature. 352 (6332): 222–223. Bibcode:1991Natur.352..222T. doi:10.1038/352222a0.
  10. ^ a b Iwasa, Y; Takenobu, T (2003). "Superconductivity, Mott Hubbard states, and molecular orbital order in intercalated fullerides". Journal of Physics: Condensed Matter. 15 (13): R495. Bibcode:2003JPCM...15R.495I. doi:10.1088/0953-8984/15/13/202.
  11. ^ Erwin, Steven; Pederson, Mark (1993). "Electronic structure of superconducting Ba6C60". Physical Review B. 47 (21): 14657–14660. arXiv:cond-mat/9301006. Bibcode:1993PhRvB..4714657E. doi:10.1103/PhysRevB.47.14657.
  12. ^ Han, J.; Gunnarsson, O.; Crespi, V. (2003). (PDF). Physical Review Letters. 90 (16): 167006. Bibcode:2003PhRvL..90p7006H. doi:10.1103/PhysRevLett.90.167006. PMID 12731998. Archived from the original (PDF) on 2019-12-28.
  13. ^ Capone, M.; Fabrizio, M; Castellani, C; Tosatti, E (2002). "Strongly Correlated Superconductivity". Science. 296 (5577): 2364–6. arXiv:cond-mat/0207058. Bibcode:2002Sci...296.2364C. doi:10.1126/science.1071122. PMID 12089436.

Further reading

  • Erwin, Steven; Pederson, Mark (1991). "Electronic structure of crystalline K6C60". Physical Review Letters. 67 (12): 1610–1613. Bibcode:1991PhRvL..67.1610E. doi:10.1103/PhysRevLett.67.1610. PMID 10044199.
  • Haddon, R. C.; Hebard, A. F.; Rosseinsky, M. J.; Murphy, D. W.; Duclos, S. J.; Lyons, K. B.; Miller, B.; Rosamilia, J. M.; Fleming, R. M.; Kortan, A. R.; Glarum, S. H.; Makhija, A. V.; Muller, A. J.; Eick, R. H.; Zahurak, S. M.; Tycko, R.; Dabbagh, G.; Thiel, F. A. (1991). "Conducting films of C60 and C70 by alkali-metal doping". Nature. 350 (6316): 320–322. Bibcode:1991Natur.350..320H. doi:10.1038/350320a0.

January 21, 2023
fulleride, chemical, compounds, containing, fullerene, anions, common, fullerides, derivatives, most, common, fullerenes, scope, area, large, because, multiple, charges, possible, fullerenes, converted, fullerides, suffix, implies, their, negatively, charged, . Fullerides are chemical compounds containing fullerene anions Common fullerides are derivatives of the most common fullerenes i e C60 and C70 The scope of the area is large because multiple charges are possible i e C60 n n 1 2 6 and all fullerenes can be converted to fullerides The suffix ide implies their negatively charged nature Cs3C60 crystal structure Fullerides can be isolated as derivatives with a wide range of cations Most heavily studied derivatives are those with alkali metals but fullerides have been prepared with organic cations Fullerides are typically dark colored solids that generally dissolve in polar organic solvents Contents 1 Structure and bonding 2 Preparation 3 Alkali metal derivatives 4 References 5 Further readingStructure and bonding EditAccording to electronic structure calculations the LUMO of C60 is a triply degenerate orbital of t1u symmetry Using the technique cyclic voltammetry C60 can be shown to undergo six reversible reductions starting at 1 V referenced to the Fc Fc couple Reduction causes only subtle changes in the structure and many derivatives exhibit disorder which obscures these effects Many fullerides are subject to Jahn Teller distortion In certain cases e g PPN 2C60 the structures are highly ordered and slight 10 pm elongation of some C C bonds is observed 1 Preparation EditFullerides have been prepared in various ways treating with alkali metals to give the alkali metal fullerides C60 2 K K2C60treating with suitable organic and organometallic reducing agents such as cobaltocene and tetrakisdimethylaminoethylene alkali metal fullerides can be subjected to cation metathesis In this way the bis triphenylphosphine iminium PPN salts have been prepared e g PPN 2C60 1 K2C60 2 PPN Cl PPN 2C60 2 KClThe fulleride salt K crypt 222 2 C60 2 salt is synthesized by treating C60 with metallic potassium in the presence of 2 2 2 cryptand Alkali metal derivatives EditCritical temperatures Tc of the fulleride saltsM3C60 Tc K Na3C60 non superconducting K3C60 18Rb3C60 28Cs3C60 40Particular attention has been paid to alkali metal Na K Rb Cs derivatives of C603 because these compounds exhibit physical properties resulting from intercluster interactions such as metallic behavior In contrast in C60 the individual molecules interact only weakly i e with essentially nonoverlapping bands These alkali metal derivatives are sometimes viewed as arising by intercalation of the metal into C60 lattice Alternatively these materials are viewed as n doped fullerenes 2 Alkali metal salts of this trianion are superconducting In M3C60 M Na K Rb the M ions occupy the interstitial holes in a lattice composed of ccp lattice composed of nearly spherical C60 anions In Cs3C60 the cages are arranged in a bcc lattice In 1991 it was revealed that potassium doped C60 becomes superconducting at 18 K 255 C 3 This was the highest transition temperature for a molecular superconductor Since then superconductivity has been reported in fullerene doped with various other alkali metals 4 5 It has been shown that the superconducting transition temperature in alkaline metal doped fullerene increases with the unit cell volume V 6 7 As Cs is the largest alkali ion caesium doped fullerene is an important material in this family Superconductivity at 38 K 235 C has been reported in bulk Cs3C60 8 but only under applied pressure The highest superconducting transition temperature of 33 K 240 C at ambient pressure is reported for Cs2RbC60 9 The increase of transition temperature with the unit cell volume had been believed to be evidence for the BCS mechanism of C60 solid superconductivity because inter C60 separation can be related to an increase in the density of states on the Fermi level N eF Therefore efforts have been made to increase the interfullerene separation in particular intercalating neutral molecules into the A3C60 lattice to increase the interfullerene spacing while the valence of C60 is kept unchanged However this ammoniation technique has revealed a new aspect of fullerene intercalation compounds the Mott transition and the correlation between the orientation orbital order of C60 molecules and the magnetic structure 10 Fourfold reduced materials i e those with the stoichiometry A4C60 are insulating even though the t1u band is only partially filled 11 This apparent anomaly may be explained by the Jahn Teller effect where spontaneous deformations of high symmetry molecules induce the splitting of degenerate levels to gain the electronic energy The Jahn Teller type electron phonon interaction is strong enough in C60 solids to destroy the band picture for particular valence states 10 A narrow band or strongly correlated electronic system and degenerated ground states are relevant to explaining superconductivity in fulleride solids When the interelectron repulsion U is greater than the bandwidth an insulating localized electron ground state is produced in the simple Mott Hubbard model This explains the absence of superconductivity at ambient pressure in caesium doped C60 solids 8 Electron correlation driven localization of the t1u electrons exceeds the critical value leading to the Mott insulator The application of high pressure decreases the interfullerene spacing therefore caesium doped C60 solids turn to metallic and superconducting A fully developed theory of C60 solids superconductivity is lacking but it has been widely accepted that strong electronic correlations and the Jahn Teller electron phonon coupling 12 produce local electron pairings that show a high transition temperature close to the insulator metal transition 13 References Edit a b Reed Christopher A Bolskar Robert D 2000 Discrete Fulleride Anions and Fullerenium Cations PDF Chemical Reviews 100 3 1075 1120 doi 10 1021 cr980017o a href Template Cite journal html title Template Cite journal cite journal a CS1 maint uses authors parameter link Gunnarsson O 1997 Superconductivity in fullerides Reviews of Modern Physics 69 2 575 606 arXiv cond mat 9611150 Bibcode 1997RvMP 69 575G doi 10 1103 RevModPhys 69 575 Hebard A F Rosseinsky M J Haddon R C Murphy D W Glarum S H Palstra T T M Ramirez A P Kortan A R 1991 Superconductivity at 18 K in potassium doped C60 PDF Nature 350 6319 600 601 Bibcode 1991Natur 350 600H doi 10 1038 350600a0 hdl 11370 3709b8a7 6fc1 4b32 8842 ce9b5355b5e4 Rosseinsky M Ramirez A Glarum S Murphy D Haddon R Hebard A Palstra T Kortan A Zahurak S Makhija A 1991 Superconductivity at 28 K in RbxC60 PDF Physical Review Letters 66 21 2830 2832 Bibcode 1991PhRvL 66 2830R doi 10 1103 PhysRevLett 66 2830 PMID 10043627 Chen C C Kelty S P Lieber C M 1991 RbxK1 x 3C60 Superconductors Formation of a Continuous Series of Solid Solutions Science 253 5022 886 8 Bibcode 1991Sci 253 886C doi 10 1126 science 253 5022 886 PMID 17751824 Zhou O Zhu Q Fischer J E Coustel N Vaughan G B M Heiney P A McCauley J P Smith A B 1992 Compressibility of M3C60 Fullerene Superconductors Relation Between Tc and Lattice Parameter Science 255 5046 833 5 Bibcode 1992Sci 255 833Z doi 10 1126 science 255 5046 833 PMID 17756430 Brown Craig Takenobu Taishi Kordatos Konstantinos Prassides Kosmas Iwasa Yoshihiro Tanigaki Katsumi 1999 Pressure dependence of superconductivity in the Na2Rb0 5Cs0 5C60 fulleride Physical Review B 59 6 4439 4444 Bibcode 1999PhRvB 59 4439B doi 10 1103 PhysRevB 59 4439 a b Ganin Alexey Y Takabayashi Yasuhiro Khimyak Yaroslav Z Margadonna Serena Tamai Anna Rosseinsky Matthew J Prassides Kosmas 2008 Bulk superconductivity at 38 K in a molecular system Nature Materials 7 5 367 71 Bibcode 2008NatMa 7 367G doi 10 1038 nmat2179 PMID 18425134 Tanigaki K Ebbesen T W Saito S Mizuki J Tsai J S Kubo Y Kuroshima S 1991 Superconductivity at 33 K in CsxRbyC60 Nature 352 6332 222 223 Bibcode 1991Natur 352 222T doi 10 1038 352222a0 a b Iwasa Y Takenobu T 2003 Superconductivity Mott Hubbard states and molecular orbital order in intercalated fullerides Journal of Physics Condensed Matter 15 13 R495 Bibcode 2003JPCM 15R 495I doi 10 1088 0953 8984 15 13 202 Erwin Steven Pederson Mark 1993 Electronic structure of superconducting Ba6C60 Physical Review B 47 21 14657 14660 arXiv cond mat 9301006 Bibcode 1993PhRvB 4714657E doi 10 1103 PhysRevB 47 14657 Han J Gunnarsson O Crespi V 2003 Strong Superconductivity with Local Jahn Teller Phonons in C60 Solids PDF Physical Review Letters 90 16 167006 Bibcode 2003PhRvL 90p7006H doi 10 1103 PhysRevLett 90 167006 PMID 12731998 Archived from the original PDF on 2019 12 28 Capone M Fabrizio M Castellani C Tosatti E 2002 Strongly Correlated Superconductivity Science 296 5577 2364 6 arXiv cond mat 0207058 Bibcode 2002Sci 296 2364C doi 10 1126 science 1071122 PMID 12089436 Further reading EditErwin Steven Pederson Mark 1991 Electronic structure of crystalline K6C60 Physical Review Letters 67 12 1610 1613 Bibcode 1991PhRvL 67 1610E doi 10 1103 PhysRevLett 67 1610 PMID 10044199 Haddon R C Hebard A F Rosseinsky M J Murphy D W Duclos S J Lyons K B Miller B Rosamilia J M Fleming R M Kortan A R Glarum S H Makhija A V Muller A J Eick R H Zahurak S M Tycko R Dabbagh G Thiel F A 1991 Conducting films of C60 and C70 by alkali metal doping Nature 350 6316 320 322 Bibcode 1991Natur 350 320H doi 10 1038 350320a0 Retrieved from https en wikipedia org w index php title Fulleride amp oldid 1058044703, wikipedia, wiki, book, books, library,

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