Carbyne
In chemistry, a carbyne is a monovalent carbon radical species containing an electrically neutral univalent carbon atom with three non-bonded electrons.[1]
Gas phase/reactive intermediate
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.[2] The carbon atom was generally found to be an electronic doublet: the valence electrons are arranged as one radical (unpaired electron) and one electron pair, leaving a vacant atomic orbital, rather than being a tri-radical. The carbon atom is a complex hybridization, so the simple Hund's rule analysis of a simple atom containing 3 p orbitals (or 4 sp3 hybrids) is not correct.
doublet (1 radical, 1 pair, 1 vacant orbital) 
quartet (3 radicals)
Organometallic ligand
Carbynes are incorporated in Transition metal carbyne complexes[3][4] as a trivalent ligand. 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 [W(CO)6] with Lithium diisopropylamide to form [(iPr2N)(OLi)C=W(CO)5]. This is then reacted with either oxalyl bromide or triphenylphosphine dibromide followed by triphenyl phosphine. Another method is to treat a methoxy metal carbene with a lewis acid.[5]
References
- ^ IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "carbynes". doi:10.1351/goldbook.C00854
- ^ "Chemistry of carbynes: reaction of CF, CCl, and CBr with alkenes". J. Am. Chem. Soc. 105: 2489–2490. 1983. doi:10.1021/ja00346a072.
{{cite journal}}: Cite uses deprecated parameter|authors=(help) - ^ Furno, F.; Fox, T.; Berke, H. trans-W(CMes)(dmpe)2H: a W+ H– ion pair (PDF). EURO-HYDRIDES 2000.
{{cite conference}}: External link in|conferenceurl=|conferenceurl=ignored (|conference-url=suggested) (help)CS1 maint: multiple names: authors list (link) - ^ 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.
- ^ Jaeger, M.; Stumpf, R.; Troll, C.; Fischer, H. (2000). "Novel hepta-coordinated molybdenum(II) and tungsten(II) carbene complexes by oxidative decarbonylation of Mo(0) and W(0) carbene complexes". Chem. Commun.: 931–932. doi:10.1039/B002228O.
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