Successive insertion of tetrafluoroethylene and CO and of tetrafluoroethylene and acetylenes into aryne-nickel(0) bonds

Article abstract of DOI:10.1039/a702375h

Aryne-nickel complexes [Ni(η²-C₆H₄)L₂] [L₂ = 2PEt₃ or dcpe; dcpe = (C₆H¹¹)²PCH₂CH₂P(C ₆H₁₁)₂] and [Ni(η²-C₁₀H₆)(PEt₃)₂] reacted readily with C₂F₄ to form the corresponding five-membered tetrafluoro-substituted nickelacycles [Ni(C₆H₄CF₂CF₂-2)L₂] (L₂ = dcpe or 2PEt₃) and [Ni(2-C₁₀H₆CF₂CF₂-3)(PEt ₃)₂], respectively. The complex [Ni(C₆H₄CF₂CF₂-2)(dcpe)] is very stable towards air, whereas the PEt₃ analogues react readily to give μ-aryloxo dimers. The naphthalene-based dimer [{Ni(μ-2-OC¹⁰H₆CF₂CF₂-3)(PEt ₃)}₂] has been structurally characterized. The complexes [Ni(C₆H₄CF₂CF₂-2)L₂] insert CO into their aryl-nickel bonds to form six-membered acyl complexes [Ni{C(O)C₆H₄CF₂CF₂-2} L₂] (L₂ = dcpe or 2PEt₃) and, after CO-induced reductive elimination, 2,2,3,3-tetrafluoroindanone. The dcpe acyl complex has also been shown to undergo reaction with air to form the carboxylato complex [Ni{OC(O)C₆H₄CF₂CF₂-2}(dcpe)], whose structure has been confirmed by X-ray crystallography. Some insertions of acetylenes into the aryl-nickel bonds of [Ni(C₆H₄CF₂CF₂-2)L₂] are also reported.