TRIPODAL AMIDO-TITANIUM AND AMIDO-ZIRCONIUM COMPLEXES CONTAINING A TRISILYLSILANE-DERIVED LIGAND FRAMEWORK

A series of amido-titanium and -zirconium complexes containing a tripo dal amide with a trisilylsilane ligand framework has been prepared. Th e primary isolable products in the reaction of SiMe (SiMe(2)NHR)(3) (R = 4-MeC(6)H(4), 2-FC6H4 or 4-MeOC(6)H(4)) with LiBu(n) and ZrCl4 in d iethyl ether are the [Li(OEt(2))(2)Cl] adducts of which the five-co-or dinate complex [{(4-MeOC(6)H(4)NSiMe(2))(3)MeSi}Zr(mu Cl)(2)Li(OEt(2)) (2)] and the six-co-ordinate (6)H(4)NSiMe(2))(3)MeSi}Zr(mu-Cl)(2)Li(OE t(2))(2)] have been characterised by X-ray crystallography. In the lat ter one of the fluorine atoms of the peripheral 2-FC6H4 groups is weak ly coordinated to the metal. Stirring of the (Et(2)O)(2)LiCl adducts i n toluene generates the four-co-ordinate complexes [Zr{SiMe(SiMe(2)NR) (3)}Cl]. Upon reaction of [M{SiMe[SiMe(2)N(C6H4F-2)](3)}Cl] (M = Ti or Zr) with AgO3SCF3 the corresponding triflates were obtained which are sufficiently stable to be isolated, The halide ligand may be readily substituted to give the corresponding methyl, ethynyl and cyclopentadi enyl complexes.