Evidence of the formation of zerovalent palladium from Pd(OAc)2 and triphenylphosphine

Article abstract of DOI:10.1021/om00045a012

The mixture Pd(OAc)₂ + nPPh₃ (n ≥ 2) and the complex Pd(OAc)₂(PPh₃)₂ commonly used as catalysts in reactions involving aryl and vinyl halides, aryl inflates or allylic acetates spontaneously generate a zerovalent palladium complex that reacts with iodobenzene. Triphenylphosphine reduces the divalent palladium from the complex Pd(OAc)₂(PPh₃)₂ by an intramolecular reaction and is oxidized to triphenylphosphine oxide. In the presence of an excess of triphenylphosphine, the zerovalent palladium complex generated in situ has the same ³¹P NMR and cyclic voltammetry properties as those of Pd⁰(PPh₃)₄.