Thermal-stable asymmetric α-diimine nickel(II) catalysts: Synthesis, characterization, and its norbornene (co)polymerization behavior
作者：Jia-Jun Wu, Bo Deng, Jia-Hong Hou, Xin-Yue Huang, Hui-Yi Tang, Kai-Ti Wang*
關鍵字：cyclic olefin polymer, norbornene, olefin polymerization, α-diimine nickel(II) complexes
論文來源：期刊
具體來源：Applied Organometallic Chemistry
發表時間：2022年
Four asymmetric α-diimine dibromide nickel(II) complexes bearing both 2,6-diisopropyl phenyl and substituted triphenyl {[(C3H7)2C6H3NC(C10H6)CN(R2C6H3)2C6H3]NiBr2, R = CH3, Catal.1; CF3, Catal.2; OCH3, Catal.3; C6H5, Catal.4} were synthesized and characterized. In the presence of B(C6F5)3, these newly synthesized nickel complexes showed high activities toward norbornene (NBE) homopolymerization (0.84–4.88 105 gpolymer/molNi?h) under elevated temperatures, yielding high molecular weight polymers (106.5–657.9 kDa). These Ni/B catalytic systems also efficiently promoted the copolymerization of NBE with n-butyl methacrylate (n-BMA) and di(n-butyl) itaconate (n-DBI) under 70 C, respectively, affording copolymers with high molecular weight (nBMA: 95.0–235 kDa; n-DBI:35.4–52.5 kDa) and moderate polar monomer incorporations (n-BMA:1.2–6.4 mol%; n-DBI:0.8–2.8 mol%). The copolymers with polar groups showed improved solubilities. The unimodal molecular weight distribution of the resultant polymers implied the single-site catalytic behavior of these nickel catalysts toward NBE (co)polymerization. In addition, both the obtained PNB and the copolymers showed high glass transition temperature (289–345 C) and excellent thermal stability.