Triple Tandem Catalyst Mixtures for the Synthesis of Polyethylenes with Varying Structures

• Published in: Journal of the American Chemical Society 2002-12, Vol.124 (51), p.15280-15285
• Main Authors: Komon, Zachary J. A, Diamond, Gary M, Leclerc, Margarete K, Murphy, Vince, Okazaki, Miho, Bazan, Guillermo C
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Polymers with particular structures; Preparation, kinetics, thermodynamics, mechanism and catalysts
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja0283551

Tandem catalysis in a single medium presents challenges and opportunities for creating novel synthetic protocols. Thus far, only two homogeneous catalysts have been used in tandem. Herein, we report that it is possible to coordinate the action of three well-defined homogeneous catalysts to produce a wide range of branched polyethylenes from a single monomer. Thus, {[(η5-C5Me4)SiMe2(η1-NCMe3)]TiMe}{MeB(C6F5)3} (1), [(C6H5)2PC6H4C(OB(C6F5)3)O-κ2 P,O]Ni(η3-CH2C6H5) (2), and {(H3C)C[N(C6H5)]C[O-B(C6F5)3][N(C6H5)]-κ2 N,N}Ni(η3-CH2C6H5) (3) react with ethylene to produce branched polyethylene with structures that cannot be obtained using a single- or a two-component catalyst combination. The properties of the polyethylene depend on the ratio of the three catalysts. High-throughput screening techniques proved essential for optimizing reaction conditions and for probing how the catalyst composition influences the polymer properties.