Octafluorocubane or perfluorocubane is an organofluorine compound with the formula C8F8, consisting of eight carbon atoms joined into a cube, with a fluorine bonded to each carbon corner. It is a colorless, sublimable solid at room temperature. It has been of longstanding theoretical interest, but was not synthesised until 2022, when it was prepared in several steps from the (CF3)2CFCH(OH)C2F5 [wd] ester of carboxycubane, beginning with its heptafluorination. According to X-ray crystallography, the C–C distances (1.570 Å) in octafluorocubane are consistent in length with those in the parent cubane (1.572 Å).[1]

Octafluorocubane
Names
IUPAC name
1,2,3,4,5,6,7,8-octafluorocubane
Other names
perfluorocubane
Identifiers
3D model (JSmol)
ChemSpider
  • InChI=1S/C8F8/c9-1-2(10)5(13)3(1,11)7(15)4(1,12)6(2,14)8(5,7)16
    Key: DLEOOIAXKVODBG-UHFFFAOYSA-N
  • C12(C3(C4(C1(C5(C2(C3(C45F)F)F)F)F)F)F)F
Properties
C8F8
Molar mass 248.075 g·mol−1
Appearance colorless, sublimable
Density 2.429 g/cm3
Melting point 160.1–171.1 °C (320.2–340.0 °F; 433.2–444.2 K)
Related compounds
Related compounds
Octanitrocubane
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Octafluorocubane has attracted interest from theorists because of its unusual electronic structure,[2] which is indicated by its susceptibility to undergo reduction at −2.1 V to a detectable (though unstable) anion C8F8, with the free electron trapped inside of the cube.[3]

Octafluorocubane crystals exhibit intermolecular σ-hole interactions between fluorine atoms and neighboring cyclobutane ring centers. The molecule is predicted to be a strong tetrel bond donor.[1]

It was voted "favorite molecule of 2022" by readers of Chemical & Engineering News.[4]

References

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  1. 1 2 Sugiyama M, Akiyama M, Yonezawa Y, Komaguchi K, Higashi M, Nozaki K, Okazoe T (August 2022). "Electron in a cube: Synthesis and characterization of perfluorocubane as an electron acceptor". Science. 377 (6607): 756–759. Bibcode:2022Sci...377..756S. doi:10.1126/science.abq0516. PMID 35951682. S2CID 251515925.
  2. Pichierri, Fabio (September 2017). "Substituent effects in cubane and hypercubane: a DFT and QTAIM study". Theoretical Chemistry Accounts. 136 (9). doi:10.1007/s00214-017-2144-5.
  3. Krafft MP, Riess JG (August 2022). "Perfluorocubane-a tiny electron guzzler" (PDF). Science. 377 (6607): 709. Bibcode:2022Sci...377..709K. doi:10.1126/science.adc9195. PMID 35951708. S2CID 251517529.
  4. Boerner, Leigh Krietsch (December 2022). "A cube catches an electron". Chemical & Engineering News. ISSN 1520-605X. Archived from the original on 26 February 2026. Retrieved 2022-12-30.