Phosphane coordination to rare earth metal centers: Monomeric, solvent-free complexes of type Cp′₂LnX with phosphanoethyl substituted cyclopentadienyl ligands

The reaction of phosphanoethyl substituted cyclopentadienides [C₅H₄CH₂CH₂PR₂]M, R=Me, Cy, t-Bu, Ph, M=Li, K with LnX₃ (Ln=rare earth metal, X=Cl^-, CF₃SO₃^-) afforded twofold substituted metal complexes of the type [C₅H₄CH₂CH₂PR₂] ₂LnX. Using the dianionic ligand Li₂[(C₅H₄CH₂CH₂) ₂PMe] phosphano bridged ansa metallocene derivatives [(C₅H₄CH₂CH₂)₂PMe]LnX (Ln=Y, Lu; X=Cl^-, CF₃SO₃^-) were isolated. The complexes are soluble in toluene, monomeric and free of solvent. According to X-ray studies on [C₅H₄CH₂CH₂PMe₂] ₂YCl, a distorted trigonal bipyramid with two axial phosphano groups and two equatorial cyclopentadienyl moieties is the structural motif, the third equatorial site being occupied by the halide ligand.