Synthesis and structural characterization of a sterically encumbered ferrocenecarboxamido diphosphine and its platinum(II) complex

• A bulky amido-diphosphine was obtained via active ester method.
• Its restricted molecular mobility is imparted by the amide linker.
• The compound forms a diplatinum(II) complex of the type [PtCl2(μ-L)]2.

{[Bis(2-(diphenylphosphino)ethyl)amino]carbonyl}ferrocene (3), a bulky ferrocenecarboxamido-diphosphine, was prepared in a good yield by the reaction of pentafluorophenyl ferrocenecarboxylate (2) with bis[2-(diphenylphosphino)ethyl]amine. The NMR data (1H VT NMR study in particular) indicated a limited molecular mobility of amide 3 that presumably results from a hindered rotation around the amide C–N bond leading to a non-equivalency of the substituents attached to the amide nitrogen. Compound 3 was further converted to the corresponding diphosphine disulfide 4 and reacted with [PtCl2(cod)] (cod = η2:η2-cycloocta-1,5-diene) to give the symmetric, ligand-bridged diplatinum complex [(μ-3)PtCl2]2 (5) having cis square-planar geometry around the Pt(II) centers. The molecular structures of 4 and 5 were determined by single-crystal X-ray diffraction analysis.

A diphosphine modified with a ferrocenecarboxamido tag was obtained via active ester method from ferrocenecarboxylic acid and bis[2-(diphenylphosphino)ethyl]amine. The compound shows a limited molecular mobility resulting from restricted rotation around the amide C–N bond and coordinates the PtCl2 fragment to form a ligand-bridged dimer with cis-P,P geometry.Figure optionsDownload as PowerPoint slide