The Stronger the Better: Donor Substituents Push Catalytic Activity of Molecular Chromium Olefin Polymerization Catalysts
作者:Helge‐Boj Hansen、Hubert Wadepohl、Markus Enders
DOI:10.1002/chem.202101586
日期:2021.8.2
pyridine-cyclopentadienyl ligands was altered systematically by the introduction of donating groups in the para-position of the pyridine. In the resulting chromium complexes an almost linear correlation between donor strength and the nitrogen-chromium distance as well as the electronic absorption maximum is experimentally observed. The connection of electron-donating groups in the ligand backbone leads to an efficient
双功能吡啶-环戊二烯基配体的供体强度通过在吡啶的对位引入供体基团而系统地改变。在所得的铬配合物中,实验观察到供体强度与氮-铬距离以及电子吸收最大值之间的几乎线性相关性。配体骨架中给电子基团的连接导致电子影响有效转移到催化活性金属中心,而不会通过空间效应对其进行限制。因此,对于先前研究的催化剂来说,催化烯烃聚合活性已经非常高,通过附加对位-氨基分别连接到螯合吡啶或喹啉。将富含电子的茚基配体与对氨基取代的吡啶结合导致迄今为止对于此类有机铬烯烃聚合催化剂观察到的最高催化活性。所得聚合物具有超高分子量,催化剂结合共聚单体的能力也非常高。