Beijing Key Laboratory of Clothing Materials R&D and Assessment, Beijing Engineering Research Center of Textile Nanofiber, School of Materials Science and Engineering, Beijing institute of Fashion Technology, Beijing 100029, China.
Key Laboratory of Engineering Plastics and Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Molecules. 2019 Mar 25;24(6):1176. doi: 10.3390/molecules24061176.
Six examples of 2-(1-arylimino)ethyl-9-arylimino-5,6,7,8-tetrahydrocycloheptapyridine-cobalt(II) chloride complexes, [2-(1-ArN)C₂H₃-9-ArN-5,6,7,8-C₅H₈C₅H₃N]CoCl₂, (Ar = 2-(C₅H₉)-6-MeC₆H₃ , 2-(C₆H)-6-MeC₆H₃ , 2-(C₈H)-6-MeC₆H₃ , 2-(C₅H₉)-4,6-Me₂C₆H₂ , 2-(C₆H)-4,6-Me₂C₆H₂ , and 2-(C₈H)-4,6-Me₂C₆H₂ ), were synthesized by the direct reaction of the corresponding -cycloalkyl substituted carbocyclic-fused bis(arylimino)pyridines (⁻) and cobalt(II) chloride in ethanol with good yields. All the synthesized ligands (⁻) and their corresponding cobalt complexes (⁻) were fully characterized by FT-IR, ¹H/C-NMR spectroscopy and elemental analysis. The crystal structure of and revealed that the ring puckering of both the -cyclohexyl/cyclooctyl substituents and the one pyridine-fused seven-membered ring; a square-based pyramidal geometry is conferred around the metal center. On treatment with either methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), all the six complexes showed high activities (up to 4.09 × 10⁶ g of PE mol (Co) h) toward ethylene polymerization at temperatures between 20 °C and 70 °C with the catalytic activities correlating with the type of -cycloalkyl substituent: Cyclopentyl ( and ) > cyclohexyl ( and ) > cyclooctyl ( and ) for either R = H or Me and afforded strictly linear polyethylene ( > 130 °C). The narrow unimodal distributions of the resulting polymers are consistent with single-site active species for the precatalyst. Furthermore, compared to the previously reported cobalt analogues, the titled precatalysts exhibited good thermo-stability (up to 70 °C) and possessed longer lifetime along with a higher molecular weight of PE (: 9.2~25.3 kg mol).
六种 2-(1-芳基亚氨基)乙基-9-芳基亚氨基-5,6,7,8-四氢环庚并吡啶-钴(II)氯化物配合物，[2-(1-ArN)C₂H₃-9-ArN-5,6,7,8-C₅H₈C₅H₃N]CoCl₂，（Ar = 2-(C₅H₉)-6-MeC₆H₃, 2-(C₆H)-6-MeC₆H₃, 2-(C₈H)-6-MeC₆H₃, 2-(C₅H₉)-4,6-Me₂C₆H₂, 2-(C₆H)-4,6-Me₂C₆H₂, 和 2-(C₈H)-4,6-Me₂C₆H₂ )，通过相应的 -环烷基取代的碳环稠合双(芳基亚氨基)吡啶（⁻）和氯化钴（II）在乙醇中的直接反应合成，产率良好。所有合成的配体（⁻）及其相应的钴配合物（⁻）均通过 FT-IR、¹H/C-NMR 光谱和元素分析进行了充分表征。和的晶体结构表明，环戊基/环辛基取代基和一个吡啶稠合的七元环的环扭转；赋予金属中心一个正方形底面的金字塔几何形状。用甲基铝氧烷（MAO）或改性甲基铝氧烷（MMAO）处理时，所有六种配合物在 20 °C 至 70 °C 的温度范围内对乙烯聚合表现出高活性（高达 4.09 × 10⁶ g 的 PE mol (Co) h），催化活性与 -环烷基取代基的类型相关：环戊基（和）>环己基（和）>环辛基（和），对于 R = H 或 Me，得到严格的线性聚乙烯（> 130 °C）。所得聚合物的窄单峰分布与前催化剂的单活性位一致。此外，与之前报道的钴类似物相比，标题前催化剂表现出良好的热稳定性（高达 70 °C），并具有更长的寿命和更高的 PE 分子量（：9.2~25.3 kg mol）。
