Palladium Complexes with Metallocene-Bridged Bidentate Diphosphine Ligands: Synthesis, Structure, and Catalytic Activity in Amination and Cross-Coupling Reactions

The syntheses and characterization of series of new metallocene-bridged diphosphines and the structures
of complexes of some of them with Pd(II) are reported. These complexes were examined as the catalysts
in amination reactions of halogenoarenes and in the Suzuki reaction. The complexes based on ruthenocene
(2) and osmocene (3) showed lower activities then the palladium complex with dppf in amination reactions
and the same activities in the Suzuki reaction. New palladium complexes with the bidentate bulky and
electron-rich ligands Fe(η5-C5H4P(o-PriC6H4)2)2 (6) and Fe(η5-C5H4P(o-MeOC6H4)2)2 (5) showed a very
high catalytic activity in amination and Suzuki coupling of aryl bromides. A complex with ligand 6 was
used in the amination of 4-bromotoluene by primary and secondary amines and showed excellent activity.