The five unsymmetrical ligands 2-[1-(2,6-dibenzhydryl-4-tert-butylphenylimino)ethyl]-6-[1-(arylimino)ethyl]pyridine (aryl = 2,6-Me₂C₆H₃ (L1), 2,6-Et₂C₆H₃ (L2), 2,6-iPr₂C₆H₃ (L3), 2,4,6-Me₃C₆H₂ (L4), 2,6-Et₂-4-MeC₆H₂ (L5)) and the symmetrical ligand 2,6-bis(1-(2,6-dibenzhydryl-4-tert-butylphenylimino)ethyl)pyridine (L6) have been prepared and characterized by FT IR and ¹H/¹³C NMR spectroscopy and elemental analysis. The treatment of L1–L6 with FeCl₂·4H₂O afforded the corresponding ferrous chloride complexes (Fe1–Fe6) in excellent yields. A distorted-square-pyramidal geometry with a τ₅ value of 0.13 is a feature of the X-ray structure of Fe3; broad paramagnetically shifted peaks are revealed in the ¹H NMR spectra for all the iron complexes in solution. On activation with either MAO or MMAO cocatalyst, all iron complexes displayed high activities with modest variations in activities at elevated temperature (up to 12.0 × 10⁶, 12.4 × 10⁶, 12.8 × 10⁶, and 13.1 × 10⁶ g of PE (mol of Fe)⁻¹ h^–1 at 50, 60, 70, and 80 °C, respectively). The activity at 80 °C is approximately 5 times higher than that of Brookhart/Gibosn’s classical iron precatalyst (Fe0) under identical conditions. Moreover, the nature of the methylaluminoxane cocatalyst employed had a marked effect in defining the end groups of the polymer chain. For example, using MAO cocatalyst, vinyl and n-propyl end groups are formed with a relative ratio of 0.66/0.44, whereas for the MMAO cocatalyst, polymer chains undergo termination with isobutyl, n-propyl, and vinyl end groups having a relative ratio of 0.49/0.33/0.18, indicating that both chain transfer to Al(R)₃ and β-hydride elimination mechanisms are functional.

中文翻译：

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同时提高用于生产饱和/不饱和聚乙烯的亚铁预催化剂的热稳定性和活性

五个不对称的配体2- [1-（2,6-二苯甲酰基-4-叔丁基苯基亚氨基）乙基] -6- [1-（芳基）乙基]吡啶（芳基= 2,6-Me ₂ C ₆ H ₃（L1），2,6-Et ₂ C ₆ H ₃（L2），2,6-iPr ₂ C ₆ H ₃（L3），2,4,6-Me ₃ C ₆ H ₂（L4），2,6 -Et ₂ -4-MeC ₆ H ₂（L5））和对称配体2,6-bis（1-（2,6-dibenzhydryl-4- tert制备了丁基丁基亚氨基）乙基）吡啶（L6），并通过红外光谱和¹ H / ¹³ C NMR光谱及元素分析对其进行了表征。用FeCl ₂ ·4H ₂ O处理L1 – L6可得到相应的氯化亚铁络合物（Fe1 – Fe6），收率极高。失真的方锥体几何形状与τ ₅值的0.13是的X射线结构的特征的Fe3 ; ¹中显示了宽顺磁位移峰溶液中所有铁配合物的1 H NMR光谱。在具有任一MAO或MMAO助催化剂活化，所有铁配合物显示与活动适度变化的高活性在升高的温度（最高达12.0×10 ⁶，12.4×10 ⁶，12.8×10 ⁶，和13.1×10 ⁶克PE的（ Fe）^-1 h ^–1分别在50、60、70和80°C时）。在相同条件下，在80°C下的活性比Brookhart / Gibosn的经典铁预催化剂（Fe0）高约5倍。此外，所使用的甲基铝氧烷助催化剂的性质在限定聚合物链的端基方面具有显著作用。例如，使用MAO助催化剂，乙烯基和正丙基端基的相对比为0.66 / 0.44，而对于MMAO助催化剂，聚合物链的末端为异丁基，正丙基和乙烯基端基，相对比为0.49 / 0.33 / 0.18，表明向Al（R）_3的链转移和β-氢化物消除机理均起作用。