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

Abstract

This article reviews the living homopolymerization and copolymerization of propene, 1-alkene and norbornene with ansadimethysilylene(fluorenyl)(amido)dimethyltitanium, Me 2 Si(g 3 -C 13 H 8 )(g 1 -N t Bu)TiMe 2 and its derivatives, correlating the effects of cocatalysts, solvents, polymerization conditions and the substituents of the fluorenyl ligand with catalytic features, such as livingness, initiation efficiency, propagation rate, syndiospecificity and copolymerization ability. The synthesis of novel olefin block copolymers and their catalytic synthesis are also introduced using this living system. Polymer Journal (2011) 43, 331-351; doi:10.1038/pj.2011 Keywords: cycloolefin copolymer; living polymerization; norbornene; propene; single-site catalyst; syndiospecific polymerization; 1-alkene A living polymerization system, in which neither chain transfer nor deactivation occurs, affords polymers with predictable molecular weights and narrow molecular weight distributions (MWDs). Living polymerization techniques are utilized for the synthesis of terminally functionalized polymers and block copolymers. Another feature of living polymerization is its simple kinetics. Because neither chain transfer nor deactivation occurs in living polymerization, the number of polymer chains (N) is equal to the number of active centers ([C*]), and the number-average molecular weight (M n ) directly reflects the propagation rate. In living polymerization, the propagation rate can be evaluated from the M n value and the polymerization time. As chain transfer via b-elimination and/or transmetalation with trialkylaluminum as a cocatalyst is inevitable in conventional Ziegler-Natta catalytic systems; homogeneous V(acac) 3 /Et 2 AlCl (where acac is acetylacetonate or its analog) had previously been the only catalytic system that produced syndiotactic-rich living polypropylene (PP) atThe development of metallocene catalysts has enabled us to produce a variety of uniform olefin copolymers and to control the stereoregularity of poly(1-alkene)s. 3,4 The success of metallocene catalysts has stimulated research on transition metal complexes for olefin polymerization, 5-7 so-called single-site catalysts, which has also resulted in various transition metal complexes for the living polymerization of olefins. 8,9 We have also developed a living polymerization system using ansa-dimethysilylene(fluorenyl)(amido)dimethyltitanium, Me 2 Si(Z 3 -C 13 H 8 )(Z 1 -N t Bu)TiMe 2 (1), combined with a suitable cocatalyst. The catalytic system allows not only a syndiospecific living polymerization of propene and a 1-alkene but also a living homopolymerization and copolymerization of norbornene with a 1-alkene. We investigated the effect of cocatalyst, solvent and the ligand of the titanium complex on propene polymerization in terms of the livingness of the system. We also synthesized novel olefin block copolymers with the living system. This article reviews the characteristics of 1-based catalysts for tailor-made polyolefins. SYNTHESIS AND STRUCTURES OF TIT...

Copolymerization of ethylene with 1,1‐disubstituted olefins catalyzed by ansa‐(fluorenyl)(cyclododecylamido)dimethyltitanium complexes

“…6 Conversely, we have been studying the fluorenyl analogues of CGCs, Me 2 Si(g 3 -R)(N t Bu)TiMe 2 [R ¼ fluorenyl (2), 2,7-t Bu 2 fluorenyl (3), 3,6-t Bu 2 fluorenyl (4)] (Scheme 1), [7][8][9] as catalysts for olefin polymerization. 10 These complexes 2-4 were found to be highly effective catalysts for homo-and co-polymerization of higher a-olefins 11 and cyclic olefins such as norbornene. [12][13][14][15][16][17][18][19][20] We assumed that the combination of cyclododecylamido and fluorenyl groups for titanium complexes should be useful to develop more effective catalysts for the polymerization of bulky 1,1-disubstituted olefins.…”

Metallocene Catalysts

“…The molecular weight of metallocene polyethylenes varies in a wide range between 18,000 and 1.5 million and can be easily lowered by increasing the temperature, raising the metallocene/ethene ratio, or by adding small amounts of hydrogen (0.1-2 mol%) (67). The molecular weight distribution can be decreased down to 1.1 by living polymerization using bis(phenoxy-imine) titanium complexes (FI catalysts) or other half-sandwich complexes (68,69). Titanium-based, half-sandwich complexes (constrained geometry catalysts) (Fig.…”

Polymeric-Based In Vitro Diagnostic Devices

“…Various COP materials are commercially available under brand names including TopasPAS (TOPAS, Florence, KY), APEL (Mitsui Chemicals, Tokyo, Japan), ARTON (Japan Synthetic Rubber, Tokyo, Japan), Zeonex, and Zeonor (ZEON Corporation, Tokyo, Japan). The difference between them is depending on the cyclic monomer and the polymerization process used during synthesis [38,39]. COP products from Topas and Apel are based on the chain copolymerization of cyclic monomers with ethene, and Arton, Zeonex, and Zeonor are ring-opening metathesis polymerization of cyclic monomers followed by hydrogenation [26,40].…”