Carbyne
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In chemistry, a carbyne is a monovalent carbon radical species. It occurs in several ways.
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[edit] Gas phase
A carbyne can occur as a short-lived reactive intermediate. For instance, fluoromethylidyne (CF) can be detected in the gas phase by spectroscopy as an intermediate in the flash photolysis of CHFBr2.[1]
[edit] Organometallic
Carbynes are incorporated in metal carbyne complexes.[2] [3] For example, in [WBr(CO)2(2,2'-bipyridine)C-Aryl] and [WBr(CO)2(PPh3)2C-NR2]. An example of how to make such a compound would be to react [(CO)6] with Lithium diisopropylamide to form [(iPr2N)(OLi)C=W(CO)5]. This is then reacted with either oxalyl bromide or Br-Br-PPh3 followed by triphenyl phosphine. Another method is to treat a methoxy metal carbene with a lewis acid. [4]
[edit] Form of carbon
Carbyne, or polyyne, is also another name for Linear Acetylenic Carbon[5] (LAC), the carbon allotrope that has the chemical structure[6] -(C:::C)n- . Carbon in this modification is linear with sp orbital hybridisation, and is a polymer with alternating single and triple bonds. This type of carbyne is of considerable interest to nanotechnology as its Young's modulus is forty times that of the hardest known material — diamond.[7]
[edit] References
- ^ Chemistry of carbynes: reaction of CF, CCl, and CBr with alkenes B. P. Ruzsicska, A. Jodhan, H. K. J. Choi, O. P. Strausz, T. N. Bell; J. Am. Chem. Soc.; 1983; 105(8); 2489-2490.
- ^ http://www.u-bourgogne.fr/EuroH-2000/furno.pdf
- ^ Details of their reactivity and that of the related carbenes is shown at http://www.thieme-chemistry.com/thieme-chemistry/sos/info/include/pdf/sc02.pdf.
- ^ http://pubs.rsc.org/ej/CC/2000/b002228o.pdf
- ^ Dangerously Seeking Linear Carbon, Ray H. Baughman, Science 19 May 2006: Vol. 312. no. 5776, pp. 1009-1110.
- ^ Carbyne and Carbynoid Structures Series: Physics and Chemistry of Materials with Low-Dimensional Structures, Vol. 21 Heimann, R.B.; Evsyukov, S.E.; Kavan, L. (Eds.) 1999, p.452, Hardcover ISBN 0-7923-5323-4
- ^ Harder than Diamond: Determining the Cross-Sectional Area and Young's Modulus of Molecular Rods, Lior Itzhaki et al, Angew. Chem. Int. Ed. 2005, 44, 7432-7435.
[edit] See also
- http://www.sciencemag.org/cgi/content/abstract/267/5196/362
- Acetylene Chemistry
- Linear carbon allotrope – carbon atom wires prepared by pyrolysis of starch
- Synthesis of LAC - "the sp carbon allotrope"
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