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

Abstract

Aryne–nickel complexes [Ni(η 2 -C 6 H 4 )L 2 ] [L 2 = 2PEt 3 or dcpe; dcpe = (C 6 H 11 ) 2 PCH 2 CH 2 P(C 6 H 11 ) 2 ] and [Ni(η 2 -C 10 H 6 )(PEt 3 ) 2 ] reacted readily with C 2 F 4 to form the corresponding five-membered tetrafluoro-substituted nickelacycles [Ni(C 6 H 4 CF 2 CF 2 -2)L 2 ] (L 2 = dcpe or 2PEt 3 ) and [Ni(2-C 10 H 6 CF 2 CF 2 -3)(PEt 3 ) 2 ], respectively. The complex [Ni(C 6 H 4 CF 2 CF 2 -2)(dcpe)] is very stable towards air, whereas the PEt 3 analogues react readily to give µ-aryloxo dimers. The naphthalene-based dimer [{Ni(µ-2-OC 10 H 6 CF 2 CF 2 -3)(PEt 3 )} 2 ] has been structurally characterized. The complexes [Ni(C 6 H 4 CF 2 CF 2 -2)L 2 ] insert CO into their aryl–nickel bonds to form six-membered acyl complexes [Ni{C(O)C 6 H 4 CF 2 C F 2 -2}L 2 ] (L 2 = dcpe or 2PEt 3 ) 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)C 6 H 4 CF 2 C F 2 -2}(dcpe)], whose structure has been confirmed by X-ray crystallography. Some insertions of acetylenes into the aryl–nickel bonds of [Ni(C 6 H 4 CF 2 CF 2 -2)L 2 ] are also reported.