Reactions of [Fe3Cp2(CO)3(μ-CO)(μ3-CO)(μ3-CF3C2CF3)] with diphosphines: X-ray structure of a complex in which two tri-iron clusters are linked only by Ph2PCH2CH2PPh2

Reactions of the trinuclear iron cluster [Fe3Cp2(CO)3(μ-CO)(μ3-CO)(μ3-CF3C2CF3)] (1) with the bis(phosphino) ligands dppm and dppe give different results: dppe yields mainly the hexanuclear compound (2) in which two tri-iron cluster units are linked by the diphosphine, although a trinuclear derivative (3) with a chelating dppe ligand is also obtained as a minor product, whereas dppm displaces carbonyl to give complexes containing exclusively a single tri-iron unit, though the phosphine may be either dangling (4) or chelating (5). The complexes 2–5 have been characterised by elemental analyses and from their IR and NMR spectra, supplemented in the case of 2 by a single crystal X-ray diffraction analysis.