Preparation, molecular structure and catalytic behavior of (ArO)2Yb(NPh2)2K(THF)4 (Ar=C6H2-t-Bu3-2,4,6)

Reaction of anhydrous YbCl3 with 2 equiv. of sodium 2,4,6-tri-tert-butylphenoxide (ArONa, Ar=C6H2-t-Bu-3-2,4,6) and 2 equiv. of potassium diphenyl amide in THF afforded the first bis(aryloxo) amido-lanthanide complex of (ArO)(2)Yb(NPh2)(2)K(THF)(4) (1). In 1, the ytterbium and potassium were bridged via diphenyl amido ligands. The ytterbium metal center was coordinated to two oxygen atoms of aryloxide ligands and two nitrogen atoms of diphenyl amido ligands in a conventional distorted tetrahedral fashion, while the potassium interacted in rye-fashion with two phenyl rings of the diphenyl amido ligands besides four THF molecules. 1 displayed moderate catalytic activities for the polymerization of methyl methacrylate and acrylonitrile.