Synthesis and structural studies of some titanium and zirconium complexes with chiral bis(amide), amidinate or bis(amidinate) ligands

Reaction of bis(amide) sodium Na₂(1R,2R)-(−)-1,2-(NSiMe₃)₂-C₆H₁₀] (Na₂L¹]) with Ti(OiPr)₂Cl₂ in different conditions gave mixed-ligand complexes Ti(OiPr)Cl]L¹] (1) or Ti(OiPr)₂Cl]₂L¹] (2); 2 is a dinuclear titanium example in which Ti atoms are bridged by nitrogen and oxygen atoms simultaneously forming a distorted rhombic core. Reaction of the amine-amidinate ligand (1R,2R)-(−)-1-LiNC(Ph)N(SiMe₃)]-2-(NHSiMe₃)-C₆H₁₀(LiL²]) or rarely linked bis(amidinate) ligand Li₂(1R,2R)-(−)-1,2-{NC(Ph)N(SiMe₃)}₂-C₆H₁₀](Li₂L³]) with ZrCl₄ yielded the unbridged and bridged bis(amidinate) complexes ZrCl₂L²]₂ (3) and ZrCl₂(THF)]L³] (4), respectively; Moreover, the reaction of (1R,2R)-(−)-1-LiNC(Ph)N(SiMe₃)]-2-Li(NSiMe₃)C₆H₁₀(Li₂L²]) with Ti(OiPr)₂Cl₂ gave a new type of tridentate amido-amidinate product Ti(OiPr)₂]L²] (6), which is a distinct model compared to Ti(OiPr)₂Cl]L²] (5) yielded from LiL²]. All the products have been characterized by X-ray crystallography and the structural studies are presented detailedly comparing with relevant compounds.