Pentamethylcyclopentadienyl rhodium(III) trifluorovinyl phosphine complexes and attempted intramolecular dehydrofluorinative coupling of pentamethylcyclopentadienyl and trifluorovinyl phosphine ligands
Pentamethylcyclopentadienyl rhodium(III) trifluorovinyl phosphine complexes and attempted intramolecular dehydrofluorinative coupling of pentamethylcyclopentadienyl and trifluorovinyl phosphine ligands
Abstract
The trifluorovinyl phosphine complexes [Cp*RhCl₂{PR3−x(CF CF₂)x}] (1 x = 1, a R = Ph, b Pri, c Et; 2 x = 2, R = Ph) have been prepared by treatment of [Cp*RhCl(μ-Cl)]₂ with the relevant phosphine. The salt [Cp*RhCl(CNBut){PPh₂(CF CF₂)}]BF₄, 3, was prepared by addition of ButNC to 1a in the presence of NaBF₄. The salt [Cp*RhCl{κP,κS-(CF₂ CF)PPh(C₆H₄SMe-2)}]BF₄ was prepared as a mixture of cis (5a) and trans (5b) isomers by treatment of [Cp*RhCl(μ-Cl)]₂ with the phosphine-thioether (CF₂ CF)PPh(C₆H₄SMe-2), 4, in the presence of NaBF₄. The structures of 1a–c and 5a have been determined by single-crystal X-ray diffraction. Intramolecular dehydrofluorinative carbon–carbon coupling between pentamethylcyclopentadienyl and trifluorovinylphosphine ligands of 1a, 3 and 5 has been attempted. No reaction was observed on treatment of the neutral complex [Cp*RhCl₂{PPh₂(CF CF₂)}], 1a, with proton sponge, however, 5a underwent dehydrofluorinative coupling to yield [{η⁵,κP,κS-(C₅Me₄CH₂CF CF)PPh(C₆H₄SMe-2)}RhCl]BF₄, 6. Other reactions, in particular addition of HF across the vinyl bonds of 5, occurred leading to a mixture of products. The cation of 3 underwent similar reactions.
Type
Journal Article
Type of thesis
Series
Citation
Barnes, N., Brisdon, A.K., Nieuwenhuyzen, M., Pritchard, R.G. & Saunders, G.C. (2007). Pentamethylcyclopentadienyl rhodium(III) trifluorovinyl phosphine complexes and attempted intramolecular dehydrofluorinative coupling of pentamethylcyclopentadienyl and trifluorovinyl phosphine ligands. Journal of Fluorine Chemistry, 128(8), 943-951.
Date
2007
Publisher
Elsevier