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Abstract The silylium‐like surface species [iPr3Si][(RFO)3Al−OSi≡)] activates (N^N)Pd(CH3)Cl (N^N=Ar−N=CMeMeC=N−Ar, Ar=2,6‐bis(diphenylmethyl)‐4‐methylbenzene) by chloride ion abstraction to form [(N^N)Pd−CH3][(RFO)3Al−OSi≡)] (1). A combination of FTIR, solid‐state NMR spectroscopy, and reactions with CO or vinyl chloride establish that1shows similar reactivity patterns as (N^N)Pd(CH3)Cl activated with Na[B(ArF)4]. Multinuclear13C{27Al} RESPDOR and1H{19F} S‐REDOR experiments are consistent with a weakly coordinated ion‐pair between (N^N)Pd−CH3+and [(RFO)3Al−OSi≡)].1catalyzes the polymerization of ethylene with similar activities as [(N^N)Pd−CH3]+in solution and incorporates up to 0.4 % methyl acrylate in copolymerization reactions.1produces polymers with significantly higher molecular weight than the solution catalyst, and generates the highest molecular weight polymers currently reported in copolymerization reactions of ethylene and methylacrylate.
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Significant Polar Comonomer Enchainment in Zirconium‐Catalyzed, Masking Reagent‐Free, Ethylene Copolymerizations
Abstract In principal, the direct copolymerization of ethylene with polar comonomers should be the most efficient means to introduce functional groups into conventional polyolefins but remains a formidable challenge. Despite the tremendous advances in group 4‐centered catalysis for olefin polymerization, successful examples of ethylene + polar monomer copolymerization are rare, especially without Lewis acidic masking reagents. Here we report that certain group 4 catalysts are very effective for ethylene + CH2=CH(CH2)nNR2copolymerizations with activities up to 3400 Kg copolymer mol−1‐Zr h‐1 atm‐1, and with comonomer enchainment up to 5.5 mol % in the absence of masking reagents. Group 4 catalyst‐amino‐olefin structure–activity‐selectivity relationships reflect the preference of olefin activation over free amine coordination, which is supported by mechanistic experiments and DFT analysis. These results illuminate poorly understood facets of d0metal‐catalyzed polar olefin monomer copolymerization processes.
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- Award ID(s):
- 1856619
- PAR ID:
- 10090686
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 58
- Issue:
- 21
- ISSN:
- 1433-7851
- Page Range / eLocation ID:
- p. 7030-7034
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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