title: Facile carbon-fluorine bond activation and subsequent functionalisation of 1,1-difluoroethylene and tetrafluoroethylene promoted by adjacent metal centres.
abstract: The bridging fluoroolefin ligands in the complexes [Ir(2)(CH(3))(CO)(2)(μ-olefin)(dppm)(2)][OTf] (olefin = tetrafluoroethylene, 1,1-difluoroethylene; dppm = μ-Ph(2)PCH(2)PPh(2); OTf(-) = CF(3)SO(3)(-)) are susceptible to facile fluoride ion abstraction. Both fluoroolefin complexes react with trimethylsilyltriflate (Me(3)SiOTf) to give the corresponding fluorovinyl products by abstraction of a single fluoride ion. Although the trifluorovinyl ligand is bound to one metal, the monofluorovinyl group is bridging, bound to one metal through carbon and to the other metal through a dative bond from fluorine. Addition of two equivalents of Me(3)SiOTf to the tetrafluoroethylene-bridged species gives the difluorovinylidene-bridged product [Ir(2)(CH(3))(OTf)(CO)(2)(μ-OTf)(μ-C=CF(2))(dppm)(2)][OTf]. The 1,1-difluoroethylene species is exceedingly reactive, reacting with water to give 2-fluoropropene and [Ir(2)(CO)(2)(μ-OH)(dppm)(2)][OTf] and with carbon monoxide to give [Ir(2)(CO)(3)(μ-κ(1):η(2)-C≡CCH(3))(dppm)(2)][OTf] together with two equivalents of HF. The trifluorovinyl product [Ir(2)(κ(1)-C(2)F(3))(OTf)(CO)(2)(μ-H)(μ-CH(2))(dppm)(2)][OTf], obtained through single C-F bond activation of the tetrafluoroethylene-bridged complex, reacts with H(2) to form trifluoroethylene, allowing the facile replacement of one fluorine in C(2)F(4) with hydrogen.
authors.affiliation: Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Slaney
authors.forename: D Jason
authors.initials: DJ
authors.lastname: Anderson
authors.forename: Dusan
authors.initials: D
authors.lastname: Ristic-Petrovic
authors.forename: Robert
authors.initials: R
authors.lastname: McDonald
authors.forename: Martin
authors.initials: M
authors.lastname: Cowie
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry*; D018360:Crystallography, X-Ray; D005461:Fluorine / Q000737:chemistry*; D005466:Fluorocarbons / Q000737:chemistry*; D007495:Iridium / Q000737:chemistry*; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008670:Metals / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D014753:Vinyl Compounds / Q000737:chemistry*
chemical_list: D000475:Alkenes; D005466:Fluorocarbons; D008024:Ligands; D008670:Metals; D009942:Organometallic Compounds; D014753:Vinyl Compounds; D005461:Fluorine; C007384:1,1-difluoroethylene; D007495:Iridium; D002244:Carbon; C015531:tetrafluoroethylene