α‐keto‐β‐diimine nickel‐catalyzed olefin polymerization: Effect of ortho‐aryl substituents and preparation of stereoblock copolymers |
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Authors: | Anatolij Sokolohorskyj Ondřej Železník Ivana Císařová Johannes Lenz Albena Lederer Jan Merna |
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Affiliation: | 1. Department of Polymers, University of Chemistry and Technology Prague, Czech Republic;2. Department of Inorganic Chemistry, Faculty of Science, Charles University in Prague, Czech Republic;3. Leibniz Institute of Polymer Research, Hohe Strasse 6, D‐1069 Dresden, Germany and Technische Universit?t Dresden, Dresden, Germany |
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Abstract: | A series of α‐keto‐β‐diimine nickel complexes (Ar‐N = C(CH3)‐C(O)‐C(CH3)=N‐Ar)NiBr2; Ar = 2,6‐R‐C6H3‐, R = Me, Et, iPr, and Ar = 2,4,6‐Me3‐C6H3‐) was prepared. All corresponding ligands are unstable even under an inert atmosphere and in a freezer. Stable copper complex intermediates of ligand synthesis and ethyl substituted nickel complex were isolated and characterized by X‐ray. All nickel complexes were used for the polymerization of ethene, propylene, and hex‐1‐ene to investigate their livingness and the extent of chain‐walking. Low‐temperature propene polymerization with less bulky ortho‐substituents was less isospecific than the one with isopropyl derivative. Propene stereoblock copolymers were prepared by iPr derivative combining the polymerization at low temperature to prepare isotactic polypropylene (PP) block and at a higher temperature, supporting chain‐walking, to obtain amorphous regioirregular PP block. Alternatively, a copolymerization of propene with ethene was used for the preparation of amorphous block. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2440–2449 |
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Keywords: | α ‐keto‐β ‐diimine nickel block copolymers catalysis isotactic poly(propylene) living polymerization living olefin polymerization polyolefin stereoblock copolymers |
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