Highly Robust Palladium(II) α-Diimine Catalysts for Slow-Chain-Walking Polymerization of Ethylene and Copolymerization with Methyl Acrylate

Shengyu Dai; Xuelin Sui; Changle Chen

doi:10.1002/anie.201503708

Highly Robust Palladium(II) α-Diimine Catalysts for Slow-Chain-Walking Polymerization of Ethylene and Copolymerization with Methyl Acrylate

Angew Chem Int Ed Engl. 2015 Aug 17;54(34):9948-53. doi: 10.1002/anie.201503708. Epub 2015 Jun 26.

Authors

Shengyu Dai¹, Xuelin Sui¹, Changle Chen²

Affiliations

¹ Key Laboratory of Soft Matter Chemistry, Chinese Academy of Sciences, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, 230026 (China).
² Key Laboratory of Soft Matter Chemistry, Chinese Academy of Sciences, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, 230026 (China). changle@ustc.edu.cn.

PMID: 26119321
DOI: 10.1002/anie.201503708

Abstract

A series of sterically demanding α-diimine ligands bearing electron-donating and electron-withdrawing substituents were synthesized by an improved synthetic procedure in high yield. Subsequently, the corresponding Pd complexes were prepared and isolated by column chromatography. These Pd complexes demonstrated unique properties in ethylene polymerization, including high thermal stability and high activity, thus generating polyethylene with a high molecular weight and very low branching density. Similar properties were observed for ethylene/methyl acrylate copolymerization. Because of the high molecular weight and low branching density, the generated polyethylene and ethylene/methyl acrylate copolymer were semicrystalline solids. The (co)polymers had unique microstructures originating from the unique slow-chain-walking activity of these Pd complexes.

Keywords: chain-walking polymerization; copolymerization; diimine ligands; palladium catalysis; polar monomers.