Understanding the Insertion Pathways and Chain Walking Mechanisms of α-Diimine Nickel Catalysts for α-Olefin Polymerization: A 13C NMR Spectroscopic Investigation
| Autor: | Ivan Keresztes, Jessica R. Lamb, Olafs Daugulis, Geoffrey W. Coates, Kristine Klimovica, Anne M. LaPointe, Tulaza Vaidya, Kyle S. O’Connor |
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| Rok vydání: | 2017 |
| Předmět: |
chemistry.chemical_classification
Materials science Polymers and Plastics 010405 organic chemistry Organic Chemistry chemistry.chemical_element Polymer 010402 general chemistry Branching (polymer chemistry) Photochemistry 01 natural sciences 0104 chemical sciences Inorganic Chemistry Nickel chemistry.chemical_compound Monomer Polymerization chemistry Chain walking Polymer chemistry Materials Chemistry Coordination polymerization Diimine |
| Zdroj: | Macromolecules. 50:7010-7027 |
| ISSN: | 1520-5835 0024-9297 |
| DOI: | 10.1021/acs.macromol.7b01150 |
| Popis: | Nickel α-diimine catalysts have been previously shown to perform the chain straightening polymerization of α-olefins to produce materials with melting temperatures (Tm) similar to linear low density polyethylene (Tm = 100–113 °C). Branching defects due to mechanistic errors during the polymerization currently hinder access to high density polyethylene (Tm = 135 °C) from α-olefins. Understanding the intricacies of nickel α-diimine catalyzed α-olefin polymerization can lead to improved ligand designs that should allow production of chain-straightened polymers. We report a 13C NMR study of poly(α-olefins) produced from monomers with 13C-labeled carbons—specifically 1-decene with a 13C-label in the 2-position and 1-dodecene with a 13C-label in the ω-position—using a series of α-diimine nickel catalysts. Furthermore, we developed a mathematical model capable of quantifying the resulting 13C NMR data into eight unique insertion pathways: 2,1- or 1,2- insertion from the primary chain end position (1°), the penul... |
| Databáze: | OpenAIRE |
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