Rigid Triptycene-Based Di- and Trinuclear Salicylaldiminato Nickel Cooperative Polymerization Catalysts
Rigid Triptycene-Based Di- and Trinuclear Salicylaldiminato Nickel Cooperative Polymerization Catalysts
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DOI：
10.1021/acs.organomet.2c00505
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发表时间：
2023-02
期刊：
影响因子：
2.8
通讯作者：
Jueqin Yu;Daodong Zhang;Quanrui Wang
中科院分区：
文献类型：
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作者：
Jueqin Yu;Daodong Zhang;Quanrui Wang
具有刚性连接体的多金属结构可以将一个以上的催化活性位点紧密靠近，以通过金属间协同性控制它们在乙烯（共）聚合中的反应途径。这种优雅的概念主要限于电子系统。我们报告了一系列的单，双，和三核水杨醛亚胺镍（II）催化剂的合成的基础上的三蝶烯骨架。在乙烯（共）聚合中，三金属镍催化剂不仅表现出比单镍催化剂更高的活性，而且还实现了α-烯烃和极性氨基烯烃的提高的掺入率，而三金属镍催化剂在高达100 °C下具有热稳定性，并且实现了高达81%摩尔比的独特长链支化水平。发现三核镍催化剂对乙烯与1-己烯共聚的活性非常低，这是由于空间位阻增加。尽管催化结果比预期的要差，尤其是对于三镍配合物，但这项工作对于开发能够介导重要催化反应并提高效率和协同性的多核催化剂仍然有意义。
A multimetallic structure with a rigid linker can poise more than one catalytically active site in close proximity to control their reaction pathways in ethylene (co)polymerization by intermetallic cooperativity. This elegant concept was mainly limited to bimetallic systems. We report the synthesis of a series of mono-, bi-, and trinuclear salicylaldiminato Ni(II) catalysts based on a triptycene backbone. In ethylene (co)polymerization, the bimetallic nickel catalyst not only showed higher activity than the mononickel catalyst but also achieved an enhanced incorporation rate of α-olefin and the polar amino olefin, while the trimetallic nickel catalysts were thermally robust up to 100 °C and achieved a unique long-chain branching level up to an 81% mole ratio of all. Trinuclear nickel catalysts were found to be very less active for ethylene copolymerization with 1-hexene due to the increased steric hindrance. Although the catalytic result is worse than expected, especially for trinickel complexes, this work is still meaningful for the development of multinuclear catalysts that can mediate important catalytic reactions with enhanced efficiency and cooperativity.