(Alkyliminomethyl)phenylamido and related complexes of zirconium and titanium

Abstract

A range of trialkylsilylamido complexes of zirconium in which the silylamido functional group is attached to an o-(alkyliminomethyl)- or an o-(alkyliminoethyl)-substituted aromatic ring have been synthesised by salt elimination or aminolysis reactions and characterised by spectroscopic and diffraction methods. The monoanionic ligands (L), formally isoelectronic to the cyclopentadienyl ligand, can be introduced to zirconium by reaction of LLi with ZrCl₄ under a variety of conditions giving rise to complexes of type LZrCl₃ and L₂ZrCl₂, by reaction of LLi with Zr(NMe₂)₂Cl₂(THF)₂, and Zr(NEt₂)₂Cl₂(THF)₂ giving rise to LZrCl(NMe₂)₂Cl and LZrCl(NEt₂)₂Cl, respectively, or by reaction of LH with Zr(NMe₂)₄ giving rise to LZr(NMe₂)₃. LZr(NMe₂)₂Cl and LZr(NEt₂)₂Cl can be transformed to LZrCl₃ by reaction with Me₃SiCl, while LZr(NMe₂)₃ on heating rearranges to dimeric imido complexes by elimination of amidosilanes. Aminolysis of Zr(NMe₂)₂Cl₂(THF)₂ with LH results in a formal insertion of the imino CN into the Zr-amido bond. The combination of enolisable imine and a bulky silyl amide gave rise to a new mixed donor ligand system comprising of one silylamido and one eneamido group. Finally aminolysis of Ti(NMe₂)Cl₂ with LH resulted in the isolation of a C₃ symmetric triamido titanium complex.