The axial and equatorial bulkiness in the α-diimine Ni/Pd type complexes are two crucial parameters that govern the catalytic activity, the thermostability of precatalysts and the molecular weight as well as chain structure of the resulting polymers. In this contribution, we report the synthesis and characterization of a new family of α-diimine nickel complexes which bear the axially bulky terphenyl group and the equatorially bulky dibenzobarrelene group, and upon activation with MAO, these complexes not only displayed high activities towards ethylene polymerization, but also could give rise to ultra-high-molecular-weight polyethylenes (M_w as high as 174.8 × 10⁵) due to the efficient retardation of chain transfer reactions for ethylene polymerization. Mechanical studies revealed that the resultant polyethylenes showed typical elastomeric properties.

中文翻译：

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带有轴向大体积三联苯和赤道大体积二苯并戊烯基的α-二胺镍配合物：合成，表征和烯烃聚合研究

α-二亚胺Ni / Pd型配合物的轴向和赤道膨松度是控制催化活性，预催化剂的热稳定性以及所得聚合物的分子量和链结构的两个关键参数。在这项贡献中，我们报告了一个新的α-二亚胺镍配合物家族的合成和表征，这些配合物具有轴向大体积的三联苯基和赤道大体积的二苯并戊烯基，并且在被MAO活化后，这些配合物不仅对乙烯聚合表现出高活性，但也会产生超高分子量聚乙烯（M _w高达174.8×10 ⁵）是由于乙烯聚合反应中链转移反应的有效阻滞。力学研究表明，所得聚乙烯显示出典型的弹性体性能。