Synthesis, structure, and reactivity of cyclopentadienyl-free trimethylsilylmethyl yttrium di-tert-butylphenoxide complexes

The chemistry of yttrium with the trimethylsilylmethyl/2,6-di-tert-butyl-phenoxide ligand combination has been examined. The anionic dialkyl-diaryloxide complexes, {(Me3SiCH2)(2)Ln((OC6H3Bu2)-Bu-t-2,6)(2)}(-) (Ln = Y, Lu), were prepared and their reactivity and that of the neutral dialkyl-aryloxide complex (Me3SiCH2)(2)Y((OC6H3Bu2)-Bu-t-2,6)(THF)(2), 1, has been studied and compared with cyclopentadienyl-containing organolanthanide complexes. {(Me3SiCH2)(2)Y((OC6H3Bu2)-Bu-t-2,6)(2)} {[(THF)(3)Li](2)Cl}, 2, was prepared from the reaction of YCl3 with two equivalents of LiCH2SiMe3 and two equivalents of (LiOC6H3Bu2)-Bu-t-2,6 and crystallized with an unusual cation which can be viewed as a LiCl adduct of [Li(THF)(x)](+). [(Me3SiCH2)(2)Lu((OC6H3Bu2)-Bu-t-2,6)(2)][Li(THF)(4)](THF)(2) 3, was prepared analogously and crystallized with a conventional cation. Both 2 and 3 have distorted tetrahedral coordination geometries around the metals. Ring-opening polymerization of epsilon-caprolactone was observed for 1-3, but only complex 1 was found to polymerize ethylene. NMR and mass spectroscopic analyses show that the more reactive complex 1 also exhibits metallation reactivity with pyridine, toluene, phenylacetylene, CH3CN, Me2CHCN, PhCN, and PhCH2CN and insertion chemistry with Me3CNC, CO, CO2, PhNCO, and PhNCS. However, isolation of the organometallic products has been difficult due to the complexity of the reaction mixtures. (C) 1998 Elsevier Science S.A. All rights reserved.