Precise Control of Polyolefin Stereochemistry Using Single-Site Metal Catalysts

Abstract

Geoffrey W. Coates was born in 1966 in Evansville, IN. He received a B.A. degree in chemistry from Wabash College in 1989 working with Roy G. Miller and a Ph.D. in organic chemistry from Stanford University in 1994 with Robert M. Waymouth. After postdoctoral research with Robert H. Grubbs at the California Institute of Technology, he joined the faculty at Cornell University in 1997, where he is now Assistant Professor of Chemistry and Chemical Biology. His research interests include the development of single-site catalysts for synthesis and the preparation and characterization of well-defined polymer architectures.

Cationic polymerization of isobutyl vinyl ether using alcohols both as cationogen and catalyst‐modifying reagent: Effect of Lewis acids and alcohols on living nature

“…The deviation may be attributed to the formation of not an alkoxide but an oxo complex. A reaction of NbCl 5 and tBuOH is reported to produce NbO(OtBu) 3 and no Nb(OtBu) 5 , although other metal chlorides such as ZrCl 4 , TiCl 4 , and TaCl 5 form tetra-or penta-tert-butoxides, Zr(OtBu) 4 , Ti(OtBu) 4 , and Ta(OtBu) 5 …”

“…Subtle differences in the substituents of ligands can lead to a great improvement in catalytic activity and almost complete control of the stereoregularity of the product polymers. [1][2][3][4] Transition metal-catalyzed living radical polymerization, or ATRP, using metal complexes whose redox potentials are suitably adjusted by various ligands is another excellent example of ligand design. 5,6 Living cationic polymerization of vinyl monomers is a Lewis acid-mediated reaction.…”

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

“…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) at À78 1C. 1,2 The 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][6][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.…”

Transition metal-based polymer chemistry: a critical micro-review

“…It would certainly exceed by far the scope of this article if one attempted to give a comprehensive review on group IV-based polyole n chemistry. Fortunately, some excellent reviews on this topic, including carbocationic alkene polymerization [28], have been published quite recently and will serve as a reference for comprehensive reading [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. Nevertheless, a few aspects of this chemistry that certainly deserve to be discussed will be mentioned.…”