Chemistry:Armilenium

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Armilenium
Armilenium.svg
Names
IUPAC name
1,2,4a,5,6,8a-Hexahydro-1,2,5-methenonaphthalen-6-ylium
Other names
[3.5.3]Armilenium; 9-Tetracyclo[5.4.0.04,5.03,8]undeca-5,10-dienyl cation
Identifiers
3D model (JSmol)
Properties
C11H11
Molar mass 143.209 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references
Tracking categories (test):

Armilenium is a C11H+11 carbocation and was originally proposed as the first entirely organic sandwich compound. Named for its resemblance to an armillary sphere, NMR evidence for the carbocation was first described by Melvin J. Goldstein and Stanley A. Klein at Cornell University in 1973.[1][2][3][4][5] In subsequent 13C NMR experiments by Goldstein and Joseph P. Dinnocenzo in 1984, the C11H+11 carbocation was generated under stable ion conditions at lower temperature and at higher magnetic field than previously possible.[6] These experiments revealed the carbocation to be fluxional. Fitting of the dynamic NMR process ruled out the sandwich species even as an intermediate in the 20-fold degenerate rearrangement of the carbocation.

References

  1. "A C11H11 cation of unusual structure". Journal of the American Chemical Society 95 (3): 935–936. 1973. doi:10.1021/ja00784a058. 
  2. "Molecular rearrangements". Annual Reports on the Progress of Chemistry, Section B: Organic Chemistry. 70. The Chemical Society. 1973. p. 221. doi:10.1039/OC9737000206. ISBN 0-85186-061-3. 
  3. "Pyramidal mono- and dications: Bridge between organic and organometallic chemistry". Accounts of Chemical Research 8 (12): 413–420. 1975. doi:10.1021/ar50096a004. 
  4. "The automerization of C11H11 chlorides and the stability of their cations". Journal of the American Chemical Society 103 (21): 6530–6532. 1981. doi:10.1021/ja00411a059. 
  5. "Degenerate carbocation rearrangements". Advancements in Physical Organic Chemistry. Advances in Physical Organic Chemistry. 19. Academic Press. 1983. pp. 366–367. doi:10.1016/s0065-3160(08)60224-5. ISBN 0-12-033519-0. 
  6. "Automerization mechanism and structure of the C11H11 armilenyl cation". Journal of the American Chemical Society 106 (8): 2473–2475. 1984. doi:10.1021/ja00320a062.