The high-value utilization of propylene is a topic worthy of in-depth research. In this regard, a series of bis(imino)pyridine vanadium (III) and cobalt (II) complexes have been synthesized and employed to selectively produce valuable products, such as 4-methyl-1-pentene (4M1P) and 1-hexene (1-H), through propylene dimerization with methylaluminoxane (MAO) as a cocatalyst. The study found that when halogen substituents are introduced on the pyridine group, the catalyst's activity improves significantly. A clear reaction mechanism has been proposed: to produce 4M1P, a two-step 2,1-insertion process is involved, with catalysts having lower steric hindrance proving more favorable for achieving high selectivity. On the other hand, the production of 1-H involves a one-step 1,2-insertion followed by a one-step 2,1-insertion process. Although the steric hindrance effect benefits the initial 1,2-insertion step, it hampers the subsequent 2,1-insertion step. The steric hindrance effect counteracts the impact of the central metal, leading to a decrease in selectivity.

丙烯的高值化利用是一个值得深入研究的课题。在这方面，合成了一系列双(亚氨基)吡啶钒(III)和钴(II)络合物，并用于选择性生产有价值的产品，例如4-甲基-1-戊烯(4M1P)和1-己烯( 1-H)，通过丙烯二聚与甲基铝氧烷(MAO)作为助催化剂。研究发现，当吡啶基团上引入卤素取代基时，催化剂的活性显着提高。提出了一个明确的反应机理：为了生产4M1P，涉及两步2,1-插入过程，具有较低空间位阻的催化剂更有利于实现高选择性。另一方面，1-H 的生产涉及一步 1,2-插入，然后是一步 2,1-插入过程。尽管空间位阻效应有利于最初的 1,2-插入步骤，但它阻碍了后续的 2,1-插入步骤。位阻效应抵消了中心金属的影响，导致选择性下降。