Cyclo(18)carbon
 | |
| Names | |
|---|---|
| Preferred IUPAC name
Cyclooctadeca-1,3,5,7,9,11,13,15,17-nonayne | |
| Identifiers | |
3D model (JSmol)
|
|
| ChemSpider | |
PubChem CID
|
|
CompTox Dashboard (EPA)
|
|
| |
| |
| Properties | |
| C18 | |
| Molar mass | 216.198 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
| |
Cyclooctadeca-1,3,5,7,9,11,13,15,17-nonayne or cyclo[18]carbon is an allotrope of carbon with molecular formula C
18. The molecule is a ring of eighteen carbon atoms, connected by alternating triple and single bonds; thus, it is a polyyne and a cyclocarbon.
Cyclo[18]carbon is the smallest cyclo[n]carbon predicted to be relatively stable, with a computed strain energy of 72 kilocalories per mole.[1][2]
It is, however, difficult to synthesize. It was first observed transiently in 1987 from a high-temperature retro-Diels-Alder reaction, but was unstable under those conditions, and could not be isolated.[3]
A collaboration claimed to synthesize it in solid state in 2019 by electrochemical decarbonylation:[4][5]
The observed geometry corresponds to alternating triple bonds and single bonds, rather than a cumulene-type structure of consecutive double bonds.[5]
Cyclo[18] carbon is predicted to be a mild oxidant[6] and a semiconductor.[5]
References
- ^ George A. Adamson; Charles W. Rees (1996). "Towards the total synthesis of cyclo[n]carbons and the generation of cyclo[6]carbon". J. Chem. Soc., Perkin Trans. 1 (13): 1535–1543. doi:10.1039/P19960001535.
- ^ François Diederich; Yves Rubin; Carolyn B. Knobler; Robert L. Whetten; Kenneth E. Schriver; Kendall N. Houk; Yi Li (8 September 1989). "All-Carbon Molecules: Evidence for the Generation of Cyclo[18]carbon from a Stable Organic Precursor". Science. 245 (4922): 1088–1090. Bibcode:1989Sci...245.1088D. doi:10.1126/science.245.4922.1088. PMID 17838807. S2CID 23726682.
- ^ Diederich, François; Rubin, Yves; Chapman, Orville L.; Goroff, Nancy S. (1994). "Synthetic routes to the cyclo[n]carbons". Helvetica Chimica Acta. 77: 1441–1457. doi:10.1002/hlca.19940770522.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Kaiser, Katharina; Scriven, Lorel M.; Schulz, Fabian; Gawel, Przemyslaw; Gross, Leo; Anderson, Harry L. (15 Aug 2019). "An sp-hybridized molecular carbon allotrope, cyclo[18]carbon". Science. 365 (6459): 1299–1301. arXiv:1908.05904. Bibcode:2019Sci...365.1299K. doi:10.1126/science.aay1914. PMID 31416933. S2CID 201019470.
- ^ a b c Castelvecchi, Davide (15 August 2019). "Chemists make first-ever ring of pure carbon". Nature. 572 (7770): 426. Bibcode:2019Natur.572..426C. doi:10.1038/d41586-019-02473-z. PMID 31431741.
- ^ Stasyuk, Anton J.; Stasyuk, Olga A.; Solà, Miquel; Voityuk, Alexander A. (29 Nov 2019). "Cyclo[18]carbon: the smallest all-carbon electron acceptor". Chemical Communications. 56 (3): 352–355. doi:10.1039/c9cc08399e. hdl:10256/17613. PMID 31825030. S2CID 209316603.