Preparation and properties of ethylpalladium thiolate complexes. Reaction with organic halides leading to C–S bond formation; crystal structure of trans-[PdEt(Br)(PMe3)2]

Abstract

The complexes trans-[PdEt(SR)(PMe₃)₂](R = Ph, 1; or C₆H₄Me-p, 2) and trans-[PdMe(SPh)(PMe₃)₂]3 have been prepared by reactions of trans-[PdEt₂(PMe₃)₂] or trans-[PdMe₂(PMe₃)₂] with allyl aryl sulphides. Complex 1 reacts with various organic halides such as allyl chloride, benzyl bromide and methyl iodide to give allyl phenyl sulphide, benzyl phenyl sulphide and methyl phenyl sulphide, respectively; trans-[PdEt(X)(PMe₃)₂](X = Cl, 4; Br, 5; or I, 6) were isolated from the reaction mixtures. The complex trans-[PdEt(OPh)(PMe₃)₂(HOPh)] also reacts with allyl chloride to give allyl phenyl ether together with complex 4. The structure of complex 5 has been determined by X-ray crystallography: orthorhombic, space group Pbca with a= 12.306(3), b= 20.078(5), c= 11.753(2)Å, Z= 8, R= 0.036 and R′= 0.042. It has a square-planar co-ordination around the palladium centre. The reaction of allyl chloride with complex 1 in toluene obeys first-order kinetics in the concentrations of both allyl chloride and 1.