Ni(II) Phenoxyiminato Olefin Polymerization Catalysis: Striking Coordinative Modulation of Hyperbranched Polymer Microstructure and Stability by a Proximate Sulfonyl Group

作者：Stephenson Casey J; McInnis Jennifer P; Chen Changle; Weberski Michael P Jr; Motta Alessandro; Delferro Massimiliano^*; Marks Tobin J

来源：ACS Catalysis, 2014, 4(3): 999-1003.

DOI：10.1021/cs500114b

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

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 degrees C, FI-SO2-Ni is 18 times more active, produces polyethylene with 3.2 times greater M-W and 1.5 times branch content, and is significantly more thermally stable. The FI-SO2-Ni-derived polymer is a hyperbranched polyethylene (148 branches 1000 C-1, M-W = 3500g mol(-1)) versus that from FI-CH2-Ni (98 branches 1000 C-1, M-W = 1100g mol(-1)). DFT calculations argue that the distinctive FI-SO2-Ni catalytic behavior versus that of FI-CH2-Ni is associated with nonnegligible OSO center dot center dot center dot Ni interactions involving the activated catalyst.

• 出版日期2014-3
• 单位西北大学