Reactions of some tertiary phosphines with (but-3-enyl n-butyl sulphide)dichloropalladium(II)

Abstract

The reaction of PPh₃ with [Pd(bbs)Cl₂](1 : 1), where bbs is but-3-enyl n-butyl sulphide, gives the unusual bridged palladium(II) complex [Cl₂(Ph₃P)Pd(µ-bbs)Pd(PPh₃)Cl₂], which has been characterised by elemental analysis and X-ray photoelectron and vibrational spectroscopy. Triethylphosphine behaves differently, giving a mixture of two complexes, [Pd(PEt₃)₂Cl₂] and trans-[Pd(bbs)₂Cl₂], the latter containing unidentate bbs co-ordinated via sulphur only. Confirmation of the structure of trans-[Pd(bbs)₂Cl₂] has been obtained by preparing the complex both from palladium(II) chloride and bbs (1 : 2), and from [Pd(bbs)Cl₂] and bbs (1 : 1). All attempts to prepare cis-[Pd(PPh₃)₂Cl₂] by displacement of a chelating ligand from either a cis-dichloro or a cis-bis(triphenylphosphine) complex, including repetition of literature methods reported to yield this product, have led to the formation of trans-[Pd(PPh₃)₂Cl₂], together with the bridged complex in the case of [Pb(bbs)Cl₂].