Tripodal amido-titanium and -zirconium complexes containing a trisilylsilane-derived ligand framework
Abstract
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 (SiMe2NHR)3(R = 4-MeC6H4, 2-FC6H4 or 4-MeOC6H4) with LiBun and ZrCl4 in diethyl ether are the [Li(OEt2)2Cl] adducts of which the five-co-ordinate complex [{(4-MeOC6H4NSiMe2)3MeSi}Zr(µ-Cl)2Li(OEt2)2] and the six-co-ordinate [{(2-FC6H4NSiMe2)3MeSi}Zr(µ-Cl)2Li(OEt2)2] have been characterised by X-ray crystallography. In the latter one of the fluorine atoms of the peripheral 2-FC6H4 groups is weakly co-ordinated to the metal. Stirring of the (Et2O)2LiCl adducts in toluene generates the four-co-ordinate complexes [Zr{SiMe(SiMe2NR)3}Cl]. Upon reaction of [M{SiMe[SiMe2N(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.