In this investigation, we designed and synthesized a range of pyridine-imine Pd(II) complexes featuring 2-aryl and 6-diphenylmethyl substituents. These catalysts were specifically tailored for the preparation of hyperbranched polyethylene oils (HBPEOs) and polar-functionalized hyperbranched polyethylene oils (PFHBPEOs). The catalysts exhibited high activity in the synthesis of HBPEO, achieving rates as high as 2.97–17.67 × 10 g mol h. The resulting products were characterized by low molecular weights ranging from 307 to 500 g/mol, high branching densities of 113–138/1000C, and correspondingly low viscosities. While demonstrating moderate activity in the range of 0.7–6.2 × 10 g mol h for the synthesis of PFHBPEO, the polar-functionalized hyperbranched polymers retained similar characteristics of low molecular weight (325–436 g/mol), high branching density (112–141/1000C), and low viscosity. Notably, the PFHBPEOs obtained through this process exhibited an exceptionally high insertion ratio (7.4–16.0 mol%) of MA, with the ester group positioned terminally on the long chain branching. NMR analysis further confirmed the presence of a diverse range of branching structures, with a significant proportion of hyperbranched motifs, in both HBPEO and PFHBPEO. Importantly, variations in the catalyst structure and polymerization conditions were found to significantly influence the activity, structural features, and properties of the resulting HBPEO and PFHBPEO.

中文翻译：

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钯催化合成低粘度超支化液体聚乙烯及其极性共聚物


在这项研究中，我们设计并合成了一系列具有 2-芳基和 6-二苯甲基取代基的吡啶-亚胺 Pd(II) 配合物。这些催化剂专门用于制备超支化聚乙烯油 (HBPEO) 和极性官能化超支化聚乙烯油 (PFHBPEO)。该催化剂在 HBPEO 的合成中表现出高活性，速率高达 2.97–17.67 × 10 g mol h。所得产品具有 307 至 500 g/mol 的低分子量、113-138/1000C 的高支化密度以及相应的低粘度。虽然在 0.7–6.2 × 10 g mol h 范围内表现出中等的 PFHBPEO 合成活性，但极性官能化超支化聚合物保留了低分子量 (325–436 g/mol)、高支化密度 (112– 141/1000C)，粘度低。值得注意的是，通过此过程获得的 PFHBPEO 显示出极高的 MA 插入率（7.4–16.0 mol%），且酯基位于长链支化的末端。 NMR 分析进一步证实了 HBPEO 和 PFHPEO 中存在多种分支结构，其中具有显着比例的超支化基序。重要的是，我们发现催化剂结构和聚合条件的变化会显着影响所得 HBPEO 和 PFHBPEO 的活性、结构特征和性能。