Phenoxysalicylaldimine-Bearing Chromium(III) Precatalysts for Ethylene Polymerization

Margaret Yankey, Collins Obuah, James Darkwa

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


A series of discrete chromium(III) precatalysts, {[Cr(κ3-L1)] (1a.7H2O), {[Cr(κ3-L2)] (2a.5H2O), {[Cr(κ3-L3)] (3a.6H2O), {[Cr(κ3-L4)] (4a.10H2O), {[Cr(κ3-L5)] (5a.4H2O) and in-situ-generated chromium(III) precatalysts {[Cr(κ3-L1)] (1b), {[Cr(κ3-L2)] (2b), {[Cr(κ3-L3)] (3b), {[Cr(κ3-L4)] (4b), {[Cr(κ3-L5)] (5b) bearing 2,4-di-tert-butyl-6-{[2-(1H-imidazol-4-yl)-ethylimino]-methyl}-phenol (L1), 2,4-di-tert-butyl-6-{[2-RR-pyrazol-1-yl-ethylimino]-methyl}-phenol, R = H (L2), Me (L3), Ph (L4), and 2,4-di-tert-butyl-6-{[2-pyrid-2-yl-ethylimino]-methyl}-phenol (L5) are developed. The discrete precatalysts are characterized by IR spectroscopy, elemental analysis, and mass spectrometry. The in-situ-generated precatalysts afford a one-step process for screening chromium(III) complexes as ethylene polymerization catalysts. Upon activation with EtAlCl2, both types of precatalysts exhibit high catalytic activities up to 1.71 × 105 g mol(Cr)-1 h-1 for the formation of high-density polyethylene with molecular weights as high as 3.48 × 103 g mol-1. While the discrete precatalysts produce monomodal active catalysts at all conditions, the in-situ-generated precatalysts produce either monomodal or bimodal active catalysts, suggesting that, at certain conditions, two active catalysts are produced in the in situ reactions. (Chemical Equation Presented).

Original languageEnglish
Pages (from-to)1767-1775
Number of pages9
JournalMacromolecular Chemistry and Physics
Issue number18
Publication statusPublished - 1 Sept 2014


  • chromium
  • ethylene
  • polymerization
  • salicylaldimine

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Polymers and Plastics
  • Organic Chemistry
  • Materials Chemistry


Dive into the research topics of 'Phenoxysalicylaldimine-Bearing Chromium(III) Precatalysts for Ethylene Polymerization'. Together they form a unique fingerprint.

Cite this