[1,1′-Bis(diphenylphosphino)ferrocene]palladium(II) complexes with fluorinated benzenethiolate ligands: examination of the electronic effects in the solid state, solution and in the Pd-catalyzed Heck reaction with the catalytic system [Pd(dppf)(SRF)2]

A series of palladium thiolate complexes of the type [Pd(dppf)(SRF)2] have been synthesized in good yields by metathetical reactions of [Pd(dppf)Cl2] with [Pb(SRF)2], (SRF=−SC6F5, −SC6F4-4-H, −SC6H4-2-CF3, −SC6H4-4-F, −SC6H4-3-F) and their crystal structures determined. The effect of the different thiolates in the structural properties of the complexes both in the solid state and in solution have been analyzed. Heck coupling reactions were carried out using the complexes [Pd(dppf)(SRF)2], SRF=−SC6F5 (1), −SC6F4-4-H (2), −SC6H4-2-CF3 (3), −SC6H4-4-F (4), −SC6H4-3-F (5) as catalysts in order to examine both the effect of the thiolates and the P–Pd–P bite angles in the reaction of bromobenzene and styrene. The results obtained indicate that electron-withdrawing substituents may favor higher yields in the Pd catalyzed Heck reaction using [Pd(dppf)(SRF)2] as catalysts.