Synthetic and Structural Studies of the Cyclopentadienyl-Free Yttrium Alkyl Alkoxide and Aryloxide Complexes [(Me3Si)2CH]2Y(μ-OCMe3)2Li(THF) and [Me3SiCH2]2Y(OC6H3tBu2-2,6)(THF)2

YCl 3 reacts with 2 equiv of LiCH(SiMe 3 ) 2 and 2 equiv of LiOCMe 3 in THF to form the dialkyl dialkoxide complex [(Me 3 Si) 2 CH] 2 Y(μ-OCMe 3 ) 2 Li(THF), 1 . The yttrium in 1 is surrounded by a distorted tetrahedral arrangement of two terminal alkyl groups and two bridging alkoxide groups, and the coordination around lithium is trigonal planar. The reaction of YCl 3 with 2 equiv of LiCH 2 SiMe 3 and 1 equiv of LiOC 6 H 3 t Bu 2 -2,6 in THF forms the neutral dialkyl aryloxide complex (Me 3 SiCH 2 ) 2 Y(OC 6 H 3 t Bu 2 -2,6)(THF) 2, 2 . The coordination geometry around yttrium in 2 is a distorted trigonal bipyramid with the THF groups in the apical positions.