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

Abstract

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. Show more