Synthesis and characterization of β-diketiminate lanthanide complexes: The effect of the bulkiness of ancillary ligand on the reaction

Article abstract of DOI:10.1016/S0022-328X(03)00453-4

The reactions of ytterbium dichlorides with different β-diketiminate ligand ((Ar)NC(Me)CHC(Me)N(Ar′), Ar=Ar′=C₆ H₅ (L¹); Ar=Ar′=2,6-Me₂-C₆H₃ (L²); Ar=C₆H₅, Ar′=2,6-Pr₂ⁱ-C₆H₃ (L³)) with 1 equiv of Cp′Na were studied. It was found that the bulkiness of β-diketiminate ligand and cyclopentadienyl group both have significant effect on the above reaction. For less bulky ligands L¹ and L², the reaction affords not the expected mixed-ligand ytterbium chloride, (C₅H₅)YbLCl or (CH₃C₅H₄)YbCl, but the ligand-redistributed product (C₅H₅)₂YbL or (CH₃C₅H₄)₂YbL. For bulkier ligand L³, the desired anionic ytterbium chloride (C₅H₅)YbL³(μ-Cl)₂ Li(THF)₂ is obtained. For the smallest ligand L¹, the expected ytterbium monochloride can also be obtained using bulky C₅Me₅Na as reactant. Each of these complexes was well characterized, while several have been characterized by X-ray diffraction structure determination.