Synthesis of Group 4 [(RN-o-C6H4)(2)O](2-) complexes where R is SiMe3 or 0.5 Me2SiCH2CH2SiMe2

Complexes that contain the [(Me3SiN-o-C6H4)(2)O](2-) ligand ([1](2-)) of th e type [1]M(NMe2)(2), [1]MCl2, and [1]MMe2 have been prepared where M = Ti, Zr, or Hf. Although cations prepared by addition of [Ph3C][B(C6F5)(4)] or [PhNMe2H][B(C6F5)(4)] to [1]ZrMe2 or [1]HfMe2 could not be observed in NMR studies, addition of [(eta(5)-C5H4Me)(2)Fe][B(C6H5)(4)] to [1]HfMe2 in the presence of THF led to isolation of {[1]HfMe(THF)(2)} [B(C6H5)(4)]. An X-ra y study showed the cation to be a distorted octahedron in which the [1](2-) ligand is in the mer arrangement and is significantly twisted from a plana r NC2OC2N arrangement. The THF ligands are trans to one another. No well-be haved activity for the polymerization of I-hexene could be observed with ac tivated [1]ZrMe2, while {[1]HfMe(THF)(2)}[B(C6H5)(4)] was inactive. The rea ction between Li-2[O(o-C6H4NH)(2)] and Me2ClSiCH2CH2SiMe2Cl in THF produced a cyclic diamido/ether ligand H-2[2]. The reaction between H-2[2] and Zr(N Me2)(4) or ZrR4 (R = CH2Ph, CH2SiMe3) gave [2]Zr(NMe2)(2)(HNMe2) and Zr[2]( 2), respectively. The dimethylamine in [2]Zr(NMe2)(2)(HNMe2) could be repla ced with pyridine or 2,4-lutidine to give [2]Zr(NMe2)(2)(L) (L = pyridine o r 2,4-lutidine), which then could be converted into [2]ZrCl2(L) with excess Me3SiCl. The reaction between [2]ZrCl2(py) and two equivalents of Me3SiCH2 MgCl gave a bimetallic complex in which one of the trimethylsilyl methyl gr oups has been doubly C-H activated, as confirmed by X-ray cristallography. (C) 1999 Elsevier Science S.A. All rights reserved.