1444243-80-4Relevant academic research and scientific papers
The electronic effects on unsymmetrical Bis(imino)pyridyl iron(ii) catalyzed ethylene polymerization
Dai, Shengyu,Ge, You,Li, Gen,Xu, Guoyong
, (2020/08/11)
A series of bulky unsymmetrical bis(imino)pyridyl iron(II) complexes 1–3 with different electronic effect substituents at the para-position of the N-aryl group have been synthesized and characterized. These highly robust thermostable iron(II) complexes display very high activity (up to 2.5 × 107 g mol?1 h?1) in ethylene polymerization at high pressure, and can generate highly linear polyethylene (Tm = 131.6–138.8 °C) with high molecular weight (Mw up to 185.7 × 104 g mol?1) and broad molecular weight distributions (PDI: 2.34–13.68). The electronic effect and influence of polymerization conditions on activity and molecular weight of polyethylene are investigated in detail. The electronic perturbations show great influence on the activity and polyethylene molecular weight in ethylene polymerization. Compared with the classical isopropyl substituted iron(II) complex 4, the bulky iron(II) complexes 1–3 showed higher activity and thermal stability in ethylene polymerization at high temperature.
Synthesis, characterization and catalytic behavior toward ethylene of 2-[1-(4,6-dimethyl-2-benzhydrylphenylimino)ethyl]-6-[1-(arylimino)ethyl] pyridylmetal (iron or cobalt) chlorides
Wang, Shaoli,Li, Baixiang,Liang, Tongling,Redshaw, Carl,Li, Yuesheng,Sun, Wen-Hua
, p. 9188 - 9197 (2013/07/27)
A series of 2-[1-(4,6-dimethyl-2-benzhydrylphenylimino)ethyl]-6-[1- (arylimino)ethyl]pyridines was synthesized and used to prepare the iron(ii) and cobalt(ii) chloride complexes thereof. All organic compounds were fully characterized by elemental analysis, IR and NMR (1H/13C) spectroscopy, whilst the metal complexes were characterized by elemental analysis and IR spectroscopy as well as by single-crystal X-ray diffraction studies (for two representative cobalt complexes), which revealed that the geometry at the metal was either pseudo-square-pyramidal or trigonal bipyramidal. Upon activation with either methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), all metal complex pre-catalysts exhibited high activities for ethylene polymerization. The iron pre-catalysts show much higher activity than did their cobalt analogues; however, the iron catalytic systems generally produced polyethylene of wide molecular weight polydispersity. At elevated reaction temperature, the polyethylene was of lower molecular weight, but revealed narrow polydispersity.
