2-[1-(2,6-Dibenzhydryl-4-chlorophenylimino)ethyl]-6-[1-(arylimino)ethyl] pyridyliron(II) dichlorides: Synthesis, characterization and ethylene polymerization behavior

Cao, Xiaoping; He, Fan; Zhao, Weizhen; Cai, Zhengguo; Hao, Xiang; Shiono, Takeshi; Redshaw, Carl; Sun, Wen Hua

Abstract

A series of 2-[1-(2,6-dibenzhydryl-4-chlorophenylimino)ethyl]-6-[1- (arylimino)ethyl]pyridine ligands (L1-L5) as well as the ligand 2,6-bis[1-(2,6-dibenzhydryl-4-chloro-phenylimino)ethyl]pyridine (L6) were synthesized and reacted with FeCl2·4H2O to afford the iron(II) dichloride complexes [LFeCl2] (Fe1-Fe6). All new compounds were fully characterized by elemental and spectroscopic analysis, and the molecular structures of the complexes Fe1, Fe2 and Fe4 were determined by single-crystal X-ray diffraction, which revealed a pseudo-square-pyramidal geometry at iron. Upon activation with either MAO or MMAO, all iron pre-catalysts exhibited very high activity in ethylene polymerization with good thermal stability. To the best of our knowledge, the current system showed the highest activity amongst iron bis(imino)pyridine pre-catalysts reported to-date. The polymerization parameters were explored to determine the optimum conditions for catalytic activity, which were typically found to be 2500 eq. Al to Fe at 60 °C in the presence of MMAO, and 80 °C in the presence of MAO. The resultant polyethylene possessed a narrow molecular polydispersity index (PDI) consistent with the formation of single-site active species.

Citation

Cao, X., He, F., Zhao, W., Cai, Z., Hao, X., Shiono, T., Redshaw, C., & Sun, W. H. (2012). 2-[1-(2,6-Dibenzhydryl-4-chlorophenylimino)ethyl]-6-[1-(arylimino)ethyl] pyridyliron(II) dichlorides: Synthesis, characterization and ethylene polymerization behavior. Polymer, 53(9), 1870-1880. https://doi.org/10.1016/j.polymer.2012.02.050

• Journal Article Type: Article
• Acceptance Date: Feb 27, 2012
• Online Publication Date: Mar 2, 2012
• Publication Date: Apr 17, 2012
• Deposit Date: Jun 8, 2022
• Journal: Polymer
• Print ISSN: 0032-3861
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 53
• Issue: 9
• Pages: 1870-1880
• DOI: https://doi.org/10.1016/j.polymer.2012.02.050
• Public URL: https://hull-repository.worktribe.com/output/3622252