Synthesis, characterization and electrochemistry of [Pd(PP)MeCl] compounds with 1,1′-bis(phosphino)ferrocene ligands

Abstract

Three new [Pd(κ2-PP)MeCl] (PP = 1,1′-bis(dicyclohexylphosphino)ferrocene (dcpf), 1-diphenylphosphino-1′-ditert-butylphosphinoferrocene (dppdtbpf) or 1,1ʹ-bis(5-methyl-2-furanylphosphino)ferrocene (dfurpf)) compounds were prepared and characterized. The X-ray crystal structure of [Pd(dppdtbpf)MeCl] was obtained which allowed for unambiguous determination of the cis/trans- relationship between the methyl and chloride ligands with respect to the different phosphine groups. The oxidative electrochemistry of the three new compounds as well as that of the reported [Pd(κ2-PP)MeCl] (PP = 1,1′-bis(diphenylphosphino)ferrocene (dppf), or 1,1′-bis(diiso-propylphosphino)ferrocene (dippf)) and [Pd(κ3-dtbpf)Me]Cl (dtbpf = 1,1′- bis(ditert-butylphosphino)ferrocene) was examined. The compounds with the κ2-bis(phosphino)ferrocene ligands react with sodium tetrakis(3,5-bis(trifluoromethyl)phenylborate) to lose a chloride ligand and the catalytic activity of these compounds was investigated for the polymerization of phenylacetylene.