Stereospecific polymerization of propylene with group 4 ansa-fluorenylamidodimethyl complexes

Abstract

Group 4 [g 1 :g 3 -tert-butyl(dimethylfluorenylsilyl)amido]dimethyl complexes [t-BuNSiMe 2 Flu]MMe 2 (M = Ti, 1; Zr, 2; Hf, 3) were synthesized in a one-pot synthesis starting from the ligand, MeLi and MCl 4 (M = Ti, Zr, Hf), respectively. The structures of these complexes were determined by X-ray crystallography and the results obtained revealed that the fluorenyl ligand coordinates to center metal in a g 3 -manner irrespective of center metal employed. Propylene polymerization was conducted at 0 or 20°C in toluene by 1-3 combined with dried methylaluminoxane (MAO), which was prepared from the toluene solutions of MAO by removing free trialkylaluminiums, and HNMe 2 PhB(C 6 F 5 ) 4 in the presence of triisobutylaluminium. The 1-dried MAO system gave the polymer with syndiotactic triad (rr) of 63% at 0°C, whereas 2 and 3 did not give any polymer in the same conditions. The 2-dried MAO system gave the polymer with the highest syndiotacticity (rr = 97%) at 20°C, although the activity was low. The 3-dried MAO system did not give any polymer even at 20°C. When HNMe 2 PhB(C 6 F 5 ) 4 was used in place of dried MAO at 20°C, 1 gave almost atactic polymer, while 2 and 3 gave highly syndiotactic one (rr > 90%). These results indicate that the catalytic performance strongly depended on the center metal of the ansafluorenylamidodimethyl complexes as well as cocatalysts employed.

Living polymerization of olefins with ansa-dimethylsilylene(fluorenyl)(amido)dimethyltitanium-based catalysts

“…13 We applied route I, 14 which starts from TiCl 4 , the ligand and four molar equivalent of MeLi, to give 1 through a one-pot synthesis and succeeded in the synthesis of 1 and Zr and Hf analogs (1-Zr and 1-Hf) with 42-43% yields. 15 The fluorenyl derivatives 2-4, 16,17 the indenyl derivative 18 and CGC-Ti were also synthesized by this procedure with 20-60% yields. All of these complexes were isolated as crystals, and their molecular structures were determined by single-crystal X-ray analyses.…”

Synthesis, characterization and catalytic activity of the complex titanium bis(dimethylmalonate)–bis(diethylamido) in the polymerization of propylene

“…During the last decade, large amount of research has focused on non-metallocene related complexes such as borrolides [18], phosphinimides [19], and guanidinate type ligands [20] (where the steric and electronic properties of the ligand are similar to cyclopentadienyl) and ligands such as constrained geometry ligands (CGC) [21][22][23][24][25][26][27][28][29], diamides [30][31][32], phenoxyimine (FI) [33,34] amidinates [35,36], and b-diketiminates [37][38][39] which have been successfully used.…”

Facile Synthesis of Hydroxy‐Functionalized Cycloolefin Copolymer Using ω‐Alkenylaluminium as a Comonomer

“…Trioctylaluminium and Ph 3 CB(C 6 F 5 ) 4 provided by Tosoh Finechem Co. were used without any purification. Me 2 Si( t BuN)(fluorenyl)TiMe 2 ( 1 ) and 7‐octenyldiisobutylaluminium (ODIBA) were prepared according to the method reported previously.…”