Synthesis, characterization and reactivity of new complexes of titanium and zirconium containing a potential tridentate amidinato-cyclopentadienyl ligand

Group 4 metal complexes [M(eta(5)-C5Me4SiMe2-eta(1)-N-2R)(NMe2)(2)] (R = pyridine, pyrazine, pyrimidine, thiazole, M = Ti; R = pyridine, thiazole; M = Zr) containing the tetramethylcyclopentadienyldialkylsilyl bridged amidinato as pendant ligand, were synthesized and characterized by elemental analysis, solution H-1, C-13 and N-15 NMR spectroscopy and experimental C-13 and N-15 CPMAS in the solid state. The crystal structures of [Ti(eta(5)-C5Me4SiMe2-eta(1)-N-2R)(NMe2)(2)] (R = pyridine 2a, pyrazine 2b, pyrimidine 2c, thiazole 2d) were determined by single crystal X-ray diffraction studies. All compounds exhibit a distorted tetrahedral geometry, with the ansa-monocyclopentadienyl-amido ligands acting in a bidentate mode. The [M(eta(5)-C5Me4SiMe2-eta(1)-N-2R)(NMe2)(2)] (R = pyridine, thiazole; M = Zr, Ti) complexes are ethylene polymerization catalysts in the presence of MAO and they are active precursors in regioselective catalytic hydroamination operating with an anti-Markovnikov mechanism.