Article Cite This: Organometallics XXXX, XXX, XXX−XXX
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High-Performance Neutral Phosphine-Sulfonate Nickel(II) Catalysts for Efficient Ethylene Polymerization and Copolymerization with Polar Monomers Jian Xia,†,‡,§ Yixin Zhang,*,‡ Jianfu Zhang,*,†,§ and Zhongbao Jian*,‡
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School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, Changchun, 130022, China ‡ State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Renmin Street 5625, Changchun, 130022, China § Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun, 130022, China S Supporting Information *
ABSTRACT: Low-cost and earth-abundant nickel catalysts are of great interest for olefin copolymerization with polar monomers to generate highly desirable functionalized polyolefins. However, nickel catalysts usually suffer from poor thermal stability and low copolymer molecular weight. In this work, by combination of design strategies of sterics and electronics, a family of sterically demanding aliphatic/ aromatic-substituted phosphine-sulfonate neutral nickel complexes 1−4 {[κ2(P,O)-(menthyl)ArP(C6H4SO2O)]NiMe(pyr)} (1: Ar = (MeO)3C6H2; 2: Ar = 2-(2′,6′-(MeO)2C6H3)C6H4; 3: Ar = 2-(C6H5)C6H4; 4: Ar = 2-(2′,6′F2C6H3)C6H4) with different sterics and electronics were synthesized and fully characterized by comprehensive NMR spectroscopy, single-crystal X-ray diffraction, and elemental analysis. Among these nickel catalysts, catalysts 1 and 4 are in favor of generating polyethylenes with high molecular weights (up to 224.0 kg mol−1) in high activities (up to 1.6 × 106 g mol−1 h−1) and good thermal stabilities (up to 90 °C), while catalysts 2 and 3 suffer from low thermal stability. More remarkably, the preferred catalysts 1 and 4 are also efficient for ethylene copolymerization with a broad scope of polar monomers including vinyl trimethoxysilane, various allyl monomers, 6-chloro-1-hexene, 6-bromo-1-hexene, methyl 10-undecenoate, and hydroxymethyl norbornene. These copolymerizations exhibit moderate to high activities (up to 18.0 × 104 g mol−1 h−1), high molecular weights (23.9−165.5 kg mol−1), and relatively low incorporations (80 °C), which seriously hinders the industrial application. Therefore, there has been growing interest in the Received: December 17, 2018
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DOI: 10.1021/acs.organomet.8b00916 Organometallics XXXX, XXX, XXX−XXX
Article
Organometallics Chart 1. Diverse Nickel Catalysts for the Copolymerization of Ethylene and Polar Monomers
copolymerization of olefin and polar monomers to generate the highly linear functionalized polyolefins, the corresponding Ni(II) catalysts based on phosphine-sulfonate ligands have received much less attention. In 2012, Nozaki et al. for the first time reported that dicyclohexyl-substituted phosphine-sulfonate Ni(II) catalysts (Chart 1, VII) promote the cooligomerization of ethylene with polar allyl monomers, albeit with low activities (
