The Synthesis and Olefin Reactivity of Neutral and Cationic Tantalum Amidinate−Pentamethylcyclopentadienyl Complexes
摘要:
Cp*[MeC(NPri)(2)]TaCl3, 1, was prepared in a 60% yield by the reaction of Cp*TaCl4 with 1 equiv of Li[MeC(NPri)(2)] in THF. The structure is pseudo-octahedral with a plane of symmetry containing the amidinate ligand and bisecting the Cp*. Reaction of 1 with excess MeMgCl yielded the trimethyl derivative Cp*[MeC(NPri)(2)]TaMe3. Reaction of 1 with AgSbF6 yielded the cation [Cp*[MeC(NPri)(2)]TaCl2][SbF6]. The amidinate orientation is changed with respect to 1 such that the amidinate and the Cp* are nearly parallel. Complex 1 polymerizes ethylene upon treatment with MAO in isobutane (470 (g PE)(mmol Ta)(-1) h(-1) atm(-1)).