Synthesis, characterization, and styrene polymerization catalysis of pyridyl-functionalized indenyl rare earth metal bis(silylamide) complexes

摘要

Amine elimination of rare earth metal tris(silylamide) complexes Ln[N(SiHMe_2)_2]_3(THF)_2 with 1 equiv of the pyridyl-functionalized indenyl ligand C_9H_7CMe _2CH_2C_5H_4N-α afforded the neutral mono-indenyl-ligated rare earth metal bis(silylamide) complexes (C _9H_6CMe_2CH_2C_5H 4N-α)Ln[N(SiHMe_2)_2]_2 (Ln = Sc (1), Y (2), Nd (3)) in 70-82% isolated yields. These complexes were characterized by elemental analysis, FT-IR, NMR, and X-ray single crystal structural diffraction. X-ray determination showed that the metal centers are coordinated by one indenyl ring, one nitrogen atom from the pendent pyridyl group, and two amide groups to form a distorted tetrahedral geometry. In the presence of excess Al~iBu_3 and on activation with 1 equiv of [Ph_3C][B(C_6F_5)_4] in toluene, 1-3 became active for syndiospecific polymerization of styrene in toluene at room temperature.