A Novel Divalent Ytterbium Complex Supported by a Bridged Diamide Ligand: Synthesis and Structure of [{Me2Si(NPh)2Yb(THF)2}(μ3-Cl)(μ4-Cl){Li(THF)}2]2·2THF
Abstract
The reaction of anhydrous YbCl3 with 1 equiv. of Li2Me2Si(NPh)2 in THF, after workup, yielded a ytterbium(III) chloride [{Me2Si(NPh)2Yb}(μ2-Cl)(TMEDA)]2·3PhMe (1) (TMEDA=tetramethylethanediamine). The same reaction followed by treatment with Na-K alloy afforded a new ytterbium(II) complex supported by a bridged diamide with four coordinated LiCl molecules, [{Me2Si(NPh)2Yb(THF)2}(μ3-Cl)(μ4-Cl){Li(THF)}2]2·2THF (2) in high yield. Both complexes were structurally characterized by X-ray analysis to be dimers. Complex 1 was a chlorine-bridged dimer with ytterbium in a distorted octahedral geometry. In complex 2 two [Me2Si(NPh)2Yb(THF)2]-(μ3-Cl)[Li(THF)]2 moieties were connected with each other by two μ4-Cl bridges to form a "chair-form" framework.
