Tripodal amido-titanium and -zirconium complexes containing a trisilylsilane-derived ligand framework

A series of amido-titanium and -zirconium complexes containing a tripodal amide with a trisilylsilane ligand framework has been prepared. The 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 diethyl ether are the [Li(OEt(2))(2)Cl] adducts of which the five-co-ordinate complex [{(4-MeOC(6)H(4)NSiMe(2))(3)MeSi}Zr(mu Cl)(2)Li(OEt(2))(2)] and the six-co-ordinate [{(2-FC(6)H(4)NSiMe(2))(3)MeSi}Zr(mu-Cl)(2)Li(OEt(2))(2)] have been characterised by X-ray crystallography. In the latter one of the fluorine atoms of the peripheral 2-FC6H4 groups is weakly coordinated to the metal. Stirring of the (Et(2)O)(2)LiCl adducts in 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 cyclopentadienyl complexes.