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

Amine elimination of rare earth metal tris(silylamide) complexes Ln[N(SiHMe2)(2)](3)(THF)(2) with 1 equiv of the pyridyl-functionalized indenyl ligand C9H7CMe2CH2C5H4N-alpha afforded the neutral mono-indenyl-ligated rare earth metal bis(silylamide) complexes (C9H6CMe2CH2C5H4N-alpha)Ln[N(SiHMe2)(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 (AlBu3)-Bu-i and on activation with 1 equiv of [Ph3C][B(C6F5)(4)] in toluene, 1-3 became active for syndiospecific polymerization of styrene in toluene at room temperature. (C) 2013 Elsevier B. V. All rights reserved.