Synthesis and electrochemistry of late transition metal complexes containing 1,1′-bis(dicyclohexylphosphino)ferrocene (dcpf). The X-ray structure of [PdCl 2(dcpf)] and Buchwald–Hartwig catalysis using [PdCl 2(bisphosphinometallocene)] precursors

Abstract

The electrochemistry of 1,1′-bis(dicyclohexylylphosphino)ferrocene (dcpf) was examined in methylene chloride with tetrabutylammonium hexafluorophosphate or tetrabutylammonium tetrakis(pentafluorophenyl)borate as the supporting electrolyte. The oxidation of dcpf is complicated by a follow-up reaction. Seven new complexes containing dcpf and one new compound containing 1,1′-bis(di- tert-butylphosphino)ferrocene (dtbpf) were prepared and characterized. The new complexes were analyzed by cyclic voltammetry and the oxidation of these complexes occurred at a more positive potential than the free ligand. In addition, the X-ray structure of [PdCl 2(dcpf)] was determined and compared to other palladium complexes containing bisphosphinometallocene ligands. Five different palladium complexes containing bisphosphinometallocene ligands were examined as catalyst precursors in Buchwald–Hartwig catalysis.