Advancing polyethylene properties by incorporating NO2 moiety in 1, 2-bis(arylimino)acenaphthylnickel precatalysts: synthesis, characterization and ethylene polymerization. Issue 21 (15th May 2017)

• Record Type: Journal Article
• Authors: Mahmood, Qaiser; Zeng, Yanning; Wang, Xinxin; Sun, Yang; Sun, Wen-Hua
• Is Part Of: Dalton transactions. Volume 46:Issue 21(2017)
• Page Start: 6934
• Page End: 6947
• Publication Date: 2017-05-15
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c7dt01295k
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : A family of 1-(2, 6-dibenzhydryl-4-nitrophenylimino)-2-aryliminoacenaphthylnickel halides, on activation with either Et2 AlCl or EASC, produced ultra-high-molecular-weight highly branched polyethylenes. Abstract : A new family of nickel halides (bromidesNi1–Ni5 and chloridesNi6–Ni10 ) ligated by 1-(2, 6-dibenzhydryl-4-nitrophenylimino)-2-(arylimino)acenaphthylene (Aryl = 2, 6-Me2 C6 H3 L1, 2, 6-Et2 C6 H3 L2, 2, 6- i Pr2 C6 H3 L3, 2, 4, 6-Me3 C6 H2 L4, and 2, 6-Et2 -4-MeC6 H2 L5 ) have been prepared and well characterized, and the scope of their catalytic properties toward the polymerization of ethylene has been investigated. Upon activation with either Et2 AlCl or EASC, the nickel bromide complexes displayed better activities than their nickel chloride counterparts and produced higher-molecular-weight polyethylene in the range of 10 6 g mol −1 with a very narrow range of molecular weight distributions. In comparison with reference precatalysts with non-nitro substituents (CH3, F or Cl), the title complexes experienced a modest negative effect on catalytic activity upon replacement with a NO2 moiety (activity up to 4.61 × 10 6 g PE (mol Ni) −1 h −1 at 20 °C). Conversely, the NO2 moiety exerted a positive effect to increase the molecular weight of the resulting polyethylene, andNi4 /Et2 AlCl gave polyethylene with a maximum molecular weight of as high as 32.8 × 10 5 g mol −1, which is not only the highest among the title complexes but also higher than any literature values reported with 1, 2-diiminoacenaphthylnickel halides.