Ni(II) phenoxyiminato olefin polymerization catalysis: Striking coordinative modulation of hyperbranched polymer microstructure and stability by a proximate sulfonyl group

Casey J. Stephenson, Jennifer P. McInnis, Changle Chen, Michael P. Weberski, Alessandro Motta, Massimiliano Delferro, Tobin J. Marks

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70 Citations (Scopus)

Abstract

The synthesis, structural characterization, and ethylene polymerization properties of two neutrally charged Ni(II) phenoxyiminato catalysts are compared and contrasted. Complex FI-SO2-Ni features a -SO2- group embedded in the ligand skeleton, whereas control FI-CH2-Ni has the -SO2- replaced by a -CH2- functionality. In comparison with FI-CH2-Ni, at 25 C, FI-SO2-Ni is 18 times more active, produces polyethylene with 3.2 times greater MW and 1.5 times branch content, and is significantly more thermally stable. The FI-SO 2-Ni-derived polymer is a hyperbranched polyethylene (148 branches 1000 C-1, MW = 3500g mol-1) versus that from FI-CH2-Ni (98 branches 1000 C-1, MW = 1100g mol-1). DFT calculations argue that the distinctive FI-SO 2-Ni catalytic behavior versus that of FI-CH2-Ni is associated with nonnegligible OSO···Ni interactions involving the activated catalyst.

Original languageEnglish
Pages (from-to)999-1003
Number of pages5
JournalACS Catalysis
Volume4
Issue number3
DOIs
Publication statusPublished - Mar 7 2014

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Keywords

  • DFT calculations
  • hemilabile ligand
  • hyperbranched polyethylene
  • nickel
  • sulfonyl group

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

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