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Synthesis, characterization, and catalytic ethylene oligomerization of pyridine-imine palladium complexes

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Abstract

Two neutral five-membered pyridine-imine palladium complexes with the bulky dibenzhydryl (CH(Ph)2) substituted aniline were synthesized and fully characterized by nuclear magnetic resonance (NMR) and X-ray crystal diffraction. Well-defined cationic palladium complexes were further obtained by treatment of chloromethylpalladium complexes with sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate (NaBArF) in CH3CN. Cationic palladium complexes were capable of catalyzing ethylene oligomerization without any cocatalysts. The influences of catalyst structure, reaction temperature, and ethylene pressure on ethylene oligomerization were studied in detail. The introduction of bulky benzhydryl (CH(Ph)2) on the ortho position of the aniline moiety enhanced catalytic activity, thermal stability of the catalyst, and molecular weight of the obtained products. Highly branched oligomers with molecular weights of 600–800 g/mol and narrow polydispersities (1.03–1.12) were produced.

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Acknowledgments

This work was financially supported by the National Natural Science Foundation of China (Nos. 21374134 and 21674130), the Natural Science Foundation of Guangdong Province (No. 2014A030313160), the Fundamental Research Funds for the Central Universities (No. 17lgjc02), and PetroChina Innovation Foundation (No. 2017D-5007-0505).

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  1. School of Materials Science and Engineering, Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, Guangdong Laboratory of High-performance Polymer Composites, Sun Yat-sen University, Guangzhou, 510275, China

    Xiao-Lin Chen, Jie Gao, Heng Liao, Hai-Yang Gao & Qing Wu

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  1. Xiao-Lin Chen
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  2. Jie Gao
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Correspondence to Hai-Yang Gao.

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Invited paper for special issue of “Metal-Catalyzed Polymerization”

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Chen, XL., Gao, J., Liao, H. et al. Synthesis, characterization, and catalytic ethylene oligomerization of pyridine-imine palladium complexes. Chin J Polym Sci 36, 176–184 (2018). https://doi.org/10.1007/s10118-018-2052-8

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