Mahmood Qaiser, Li Xiaoxu, Qin Lidong, Wang Luyao, Sun Wen-Hua
Guangdong Laboratory of Chemistry and Chemical Engineering, Shantou 515031, China.
Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Dalton Trans. 2022 Oct 4;51(38):14375-14407. doi: 10.1039/d2dt02251f.
The interest in the late transition metal catalyst based design of new architectures of polyethylene (PE) has continuously been increasing over the last few years. The structure of these catalysts is predominantly important in controlling the morphological and architectural properties of the resulting polyethylene. Particularly, iminopyridine is a versatile bidentate support for Ni and Pd catalysts in ethylene (oligo)polymerization providing a wide variety of products ranging from volatile oligomers to ultra-high molecular weight polyethylene. Extensive structural modifications have been induced in the iminopyridine ligand through steric and electronic substitution, tuning the catalyst behavior in terms of activity and properties of the resulting polymer. Carbocyclic-fused iminopyridine and -oxide iminopyridine are the new state of the art iminopyridine ligand designs. In this review, we aim to summarize all the developments in mononuclear iminopyridine-nickel and -palladium catalysts for ethylene (oligo)polymerization since the first report published in 1999 to present, focusing on the correlation among the pre-catalyst, co-catalyst type, thermal stability and polymer/oligomer structure. For comparison, the structural variations in the binuclear iminopyridine-nickel catalysts are also described. The detailed comparison of the structural variations in these catalysts with respect to their polymerization performance will give deep understanding in the development of new efficient catalyst designs.
在过去几年中，基于后过渡金属催化剂设计新型聚乙烯（PE）结构的研究兴趣持续增长。这些催化剂的结构对于控制所得聚乙烯的形态和结构性质至关重要。特别是，亚氨基吡啶是乙烯（低聚）聚合中镍和钯催化剂的一种通用双齿配体，可提供从挥发性低聚物到超高分子量聚乙烯等多种产物。通过空间和电子取代对亚氨基吡啶配体进行了广泛的结构修饰，从而在活性和所得聚合物性质方面调节催化剂行为。碳环稠合亚氨基吡啶和亚氨基吡啶氧化物是最新的亚氨基吡啶配体设计。在本综述中，我们旨在总结自1999年首次报道以来至今，用于乙烯（低聚）聚合的单核亚氨基吡啶 - 镍和 - 钯催化剂的所有进展，重点关注预催化剂、助催化剂类型、热稳定性与聚合物/低聚物结构之间的相关性。为作比较，还描述了双核亚氨基吡啶 - 镍催化剂的结构变化。对这些催化剂结构变化与其聚合性能的详细比较将有助于深入理解新型高效催化剂设计的发展。
