Fluoride-induced reduction of palladium(II) and platinum(II) phosphine complexes

Article abstract of DOI:10.1021/om00042a040

A novel redox reaction involving fluoride and phosphine complexes of palladium(II) is reported. The scope of this reaction has been investigated using the ligands PPh₃, Ph₂P(CH₂)_nPPh₂ (n = 1-4), Ph₂PCH₂C(CH₃)₂CH₂PPh ₂, Ph₂PCH₃, and P(CH₂CH₂CN)₃; several solvents including DMSO, pyridine, acetonitrile, and THF; and either n-Bu₄NF·3H₂O or KF/18-crown-6 as the fluoride source. The reduction products are palladium(0) phosphine complexes for which this reaction offers a convenient synthetic route. ³¹P and ¹⁹F NMR spectra permitted identification of the initial oxidation products as difluorophosphoranes (R₃PF₂), which subsequently hydrolyzed, forming phosphine oxides if a hydrated fluoride source is used. Results implicating a fluoride-induced redox reaction in the thermal decomposition of [(Ph₃P)₃PdCl]BF₄ to yield [Pd₃Cl(PPh₂)₂(PPh₃) ₃]BF₄ are also presented. Preliminary results indicate that platinum complexes also undergo this reaction, but nickel complexes yield NiF₂. The X-ray parameters for Pd(dppp)₂ (dppp = 1,3-bis(diphenyphosphino)propane) are: monoclinic, space group C2/c (No. 15), a = 18.396 (2) A?, b = 13.290 (1) A?, c = 20.186 (2) A?, β = 109.383 (5)°, and Z = 4.