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).
Angew Chem Int Ed Engl. 2015 Aug 17;54(34):9948-53. doi: 10.1002/anie.201503708. Epub 2015 Jun 26.
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.
通过改进的合成方法，高产率地合成了一系列具有给电子和吸电子取代基的空间位阻要求较高的α-二亚胺配体。随后，通过柱层析法制备并分离得到相应的 Pd 配合物。这些 Pd 配合物在乙烯聚合中表现出独特的性质，包括高热稳定性和高活性，从而生成具有高分子量和极低支化密度的聚乙烯。在乙烯/甲基丙烯酸甲酯共聚中也观察到了类似的性质。由于高分子量和低支化密度，生成的聚乙烯和乙烯/甲基丙烯酸甲酯共聚物是半结晶固体。这些（共）聚合物具有独特的微观结构，源自这些 Pd 配合物独特的慢链行走活性。
