KAITA Shojiro RIKEN (The Institute of Physical and Chemical Research), Frontier Research System Elastomer Precision Polymerization Laboratory, Vice-Team Leader, フロンティア研究システム, 副チームリーダー (30322689)
NISHIURA Masayoshi RIKEN (The Institute of Physical and Chemical Research), Organometallic Chemistry Laboratory, Scientist, 侯有機金属化学研究室, 研究員 (30332258)
|Budget Amount *help
¥5,600,000 (Direct Cost: ¥5,600,000)
Fiscal Year 2004: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2003: ¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 2002: ¥2,000,000 (Direct Cost: ¥2,000,000)
1.1,4-Cis stereospecific polymerization of 1,3-butadiene by samarocene catalysts
The C_5Me_5R-ligated samarocene(II) complexes, (C_5Me_4R)_2Sm(THF)_x(1, R=Me ; 2, R=Et ; 3, R=i-Pr, 4, R=n-Bu, 5 ; R=TMS ; x=1 or 2), in combination with modified methylaluminoxane(MMAO) were examined in cyclohexane with respect to their catalytic performances for the polymerization of butadiene. Complexes 2-5 showed considerable promotion in both catalytic activity and regularity of the resulting polymer as compared to parent 1 : activity,3>>5〜4>2>1 ; 1,4-cis selectivity at 50℃,3〜5>4>2>1.
2.1,4-Cis stereospecific polymerization of 1,3-butadiene by cationic rare earth metallocene catalysts
Cationic metallocene complexes[(C_5Me_5)_2Ln][B(C_6F_5)_4](Ln=Pr, Nd, Gd) in combination with ^iBu_3Al efficiently induce highly 1,4-cis specific polymerization of butadiene. The activity of the Gd complex/^iBu_3Al system is high enough to exhibit good catalytic activity even at low temperature. Polymerization at -78℃ gave
polybutadiene with nearly perfect 1,4-cis microstructure (>99.9%) with sharp molecular weight distribution (M_w/M_n=1.45) and in reasonable yield.
3.Synthesis, Structural Characterization, and Novel Catalysis of Rare Earth Alkyl Complexes Bearing Silylene-Linked Cyclopentadienyl-Phosphido Ligands
The reactions of Ln(CH_2SiMe_3)_3(THF_2)(Ln=Y, Yb, Lu) with 1 equiv of Me_2Si(C_5Me_4H)(PHR)(R=Ph, Cy) afforded the first silylene-linked cyclopentadienylphosphido rare earth alkyl complexes, [Me_2Si(C_5Me_4)(μ-PR)Ln(CH_2SiMe_3)]_2. In contrast with the analogous cyclopentadienyl-amido and metallocene complexes, these complexes adopt a dimeric structure through phosphide bridging, while the alkyl ligand is placed in a terminal position. Owing to their unique steric and electronic ligand environments, most of these complexes showed much higher activity for the polymerization of ethylene and hydrosilylation of olefins than that of the conventional metallocene or amido analogues. Moreover, when treated with [Ph_3C][B(C_6F_5)_4], these complexes showed extremely high regio- and stereoselectivity for the 3,4-polymerization of isoprene, which yielded the isotactic (>99% mmmm) 3,4-poly(isoprene) selectively. This is the first example of stereospecific 3,4-polymerization of isoprene. Less