Structural studies of titanium(IV) picolinamide alkoxide and oxide derivatives

Reactions have been carried out using the titanium(IV) precursors TiCl4 and Ti(OiPr)4, with addition of two equivalents of a functionalized picolinamide ligand. The reactions with TiCl4 led to the formation of either a mononuclear titanium species, [Ti(N,O)Cl2X2] or a dinuclear titanium species [Ti(N,O)X3]2[μ-O] (X = OMe or Cl), with incorporation of one picolinamide ligand. The ligand is bound to the titanium centre as the protonated amide. The reactions with Ti(OiPr)4 resulted in the formation of mononuclear titanium bis-picolinamide species [Ti(N,O)2(OiPr)2], and also dinuclear and trinuclear products, [(N,O)Ti(OiPr)2][μ-OiPr]2 and [(N,O)Ti(OiPr)2]2[μ-OiPr]2[(OiPr)2Ti][μ3-O] respectively. In these cases the picolinamide ligand was found to be deprotonated and bound to the titanium as the iminolate. These molecules have been characterized by X-ray crystallographic analysis and structural characteristics are discussed.