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Polymerization of methyl methacrylate with non‐bridged zirconocene catalysts
Author(s) -
Shiono Takeshi,
Saito Tetsuya,
Saegusa Nobuya,
Hagihara Hideaki,
Ikeda Tomiki,
Deng Hai,
Soga Kazuo
Publication year - 1998
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/(sici)1521-3935(19980801)199:8<1573::aid-macp1573>3.0.co;2-w
Subject(s) - cyclopentadienyl complex , polymer chemistry , polymerization , tacticity , chemistry , methyl methacrylate , catalysis , polymer , metallocene , chain termination , organic chemistry , radical polymerization
Four non‐bridged dimethylzirconocene complexes, i.e., bis(η 5 ‐cyclopentadienyl)dimethylzirconium ( 1 ), (η 5 ‐cyclopentadienyl) (η 5 ‐fluorenyl)dimethylzirconium ( 2 ), bis(η 5 ‐indenyl)dimethylzirconium ( 3 ) and (η 5 ‐cyclopentadienyl)(η 5 ‐pentamethylcyclopentadienyl)dimethylzirconium ( 4 ) were synthesized and used as a catalyst for the methyl methacrylate polymerization combined with triphenylmethyl tetrakis(pentafluorophenyl)borate in the presence of ZnEt 2 or Al(i‐Bu) 3 . The catalyst activity strongly depends on the zirconocene compound and decreases in the order 2 > 1 > 3 ≫ 4 . The polymerization proceeds in a living manner when 1 and 2 are used combined with ZnEt 2 . On the other hand, stereoregularities of the resulting polymers are independent of the zirconocene compound, and syndiotactic‐rich polymers are formed by a chain‐end controlled mechanism.