Titanium and Zirconium Complexes Containing a Novel Dianionic Trifunctional Amido Ligand

The novel tridentate diamidoamine ligands [RC(2C5H4N)(CH2NSiMe3)2)2− (R = H, CH3) have been synthesized and coordinated to TiIV giving the pentacoordinate complexes [MX2(RC(2‐C5H4N)(CH2NSiMe3)2}] (M = Ti, Zr; X = Cl, Br). The crystal structure analysis of [TiBr2{HC(2‐C5H4N)(CH2)2}] (M = Ti, Zr; X = Cl, Br). The crystal structure analysis of [TiBr2{HC(2‐C5H4N)(CH2NSiMe3))] (10b) confirmed the involvement of the pyridyl function in the coordination to the meta centre occupying an apical position in the trigonal bipyramidal ligand polyhedron. alkylation of [TiCl2{H3CC(2‐C5H4N)(CH2NSiMe3)2)] (12a) with one or two molar equivalents of [RMgCl](R = PhCH2, Me3SiC2) yielded the mono‐ and dialkyl complexes [TiClR{H3CC(2‐C5H4N)(CH2NSiMe3)2)] and [TiR2(H3CC(2‐C5H4N)(CH2NSiMe3)2)] and [TiR2(H3CC(2‐C5H4N)(CH2NSiMe3)2}] in good yields. Depending on the steric demand of the alkyl group coordination or decoordination of the pyridyl group leads to four‐ or five‐coordinate species. A crystal structure analysis of the pentacoordinate complex [TiCl(CH2SiMe3){H3CC(2‐C5H4N)(CH2NSiMe3)2}] (16) was carried out.