Tertiary phosphine complexes of the f-block metals. Preparation of pentamethylcyclopentadienyl-tertiary phosphine complexes of ytterbium(II), ytterbium(III), and europium(II). Crystal structure of Yb(Me5C5)2Cl(Me2PCH2PMe2)

The diphosphine, Me2PCH2CH2PMe2, reacts with M(Me5C5)2(OEt2) to give insoluble M(Me5C5)2(Me2PCH2CH2PMe2), where M is Eu or Yb. In contrast, Me2PCH2PMe2 gives the hydrocarbon-soluble complexes M(Me5C5)2(Me2PCH2PMe2), where M is Eu or Yb. The ytterbium complex reacts with YbCl3 in toluene to give Yb(Me5C5)2Cl(Me2PCH2PMe2), and the crystal structure shows that the phosphine is acting as a monodentate ligand. Yb(Me5C5)2Cl(Me2PCH2PMe2) crystallizes in the monoclinic space group P21/c with a = 16.358 (6) A, b = 8.595 (4) A, c - 20.712 (7) A, β = 104.75 (4)0, V = 2816 A3, and d(calcd) = 1.45 g cm-3 for Z = 4 and mol wt = 615.15. Diffraction data were collected with a CAD-4 automated diffractometer, and the structure was refined to R = 0.054 for 3309 reflections with 40 < 2theta < 450 (Mo Kα radiation). The Yb is coordinated to the two Me5C5 groups, to the chlorine atom, and to one phosphorus atom of the bis(dimethylphosphino)methane ligand. The Yb-P and Yb-Cl distances are 2.94 and 2.53 A, respectively. The centroids of the C5Me5 ligands and the Cl and P atoms are in an approximate tetrahedral arrangement about the Yb atom