Direct synthesis of pentaphenylcyclopentadienyl complexes of palladium

Article abstract of DOI:10.1021/om50006a007

A series of pentaphenylcyclopentadienyl complexes of palladium(II) of the type (η⁵-C₅Ph₅)(η³-all)Pd (all = allyl, 2-chloroallyl, 2-methylallyl, 1-methylallyl, 1,1-dimethylallyl, 1-carbomethoxyallyl) have been prepared in high yield from the reaction of NaC₅Ph₅ with [(η³-all)PdCl]₂ in THF. Reaction of (η⁵-C₅Ph₅)(η³-all)Pd with phosphorus donor ligands results in the formation of zerovalent palladium complexes and coupled organic products. Reaction of (η⁵-C₅Ph₅)(η ³-2-chloroallyl)Pd with PR₃ ligands gives a series of complexes (η⁵-C₅Ph₅)PdCl(PR₃) that are not synthetically accessible from the reaction of NaC₅Ph₅ with [PdCl₂(PR₃)]₂. Pyrolysis of (η⁵-C₅Ph₅)(2-chloroallyl)Pd gives allene and the chloro-bridged dimer [(η⁵-C₅Ph₅)PdCl]₂. Reduction of this dimer by activated zinc dust in the presence of RC≡CR′ or CO gives the palladium(I) dimers (η⁵-C₅Ph₅) ₂(μ-RC≡CR′)Pd₂ and (η⁵-C₅Ph₅)₂(μ-CO) ₂Pd₂, respectively.