TY - JOUR
T1 - Ni(II) phenoxyiminato olefin polymerization catalysis
T2 - Striking coordinative modulation of hyperbranched polymer microstructure and stability by a proximate sulfonyl group
AU - Stephenson, Casey J.
AU - McInnis, Jennifer P.
AU - Chen, Changle
AU - Weberski, Michael P.
AU - Motta, Alessandro
AU - Delferro, Massimiliano
AU - Marks, Tobin J.
PY - 2014/3/7
Y1 - 2014/3/7
N2 - 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.
AB - 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.
KW - DFT calculations
KW - hemilabile ligand
KW - hyperbranched polyethylene
KW - nickel
KW - sulfonyl group
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U2 - 10.1021/cs500114b
DO - 10.1021/cs500114b
M3 - Article
AN - SCOPUS:84896762540
SN - 2155-5435
VL - 4
SP - 999
EP - 1003
JO - ACS Catalysis
JF - ACS Catalysis
IS - 3
ER -