SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF DINUCLEAR CYCLOPENTADIENYLIRON(II) COMPLEXES WITH TRITERTIARY PHOSPHINES AS BRIDGING LIGANDS

Cationic dinuclear cyclopentadienyl complexes containing tripod polytertiary phosphines as bridging ligands have been synthesized. The complexes [C5H5)Fe(CO)I-L-Fe(C5H5)]Y (L = tris(2-diphenylphosphinoethyl)amine, np3; or tris(2-dipheynylphosphinoethyl)phosphine, pp3; Y = PF6 were obtained by reaction of (C5H5Fe(CO)2I with the appropriate phosphorus ligands. The structure of the np3 derivative was determined by X-ray diffraction. The crystals are monoclinic, space group P21/n with cell dimensions a 16.393(5), b 22.317(6), c 15.345(5) Å, β 113.03(4)°, Dc 1.55 g cm-3 for Z =4. The structure was solved by three dimensional Patterson and Fourier syntheses and refined by least-squares techniques to a final conventional R factor of 0.074. The structure consists of dinuclear [(C5H5)Fe(CO)I-np3-Fe(c5H5]+ cations and PF6- anions. The nitrogen and two phosphorus atoms of the np3 ligand are bound to an cyclopentadienyliron group, while the other phosphorus atom of the ligand is bound to a cyclopentadienyliron-carbon monoxide-iodide moiety. © 1979.