Abstract:
Sterically bulky diarylmethyl-based ligands have received increasing attention in the field of late-transition-metal catalyzed olefin polymerization. Ortho-substituents may have a significant impact on the performance of diarylmethyl-based α-diimine Pd catalysts. In this contribution, a series of α-diimine Pd catalysts bearing ortho-methoxyl/hydroxyl functionalized dibenzhydryl units were prepared, characterized, and investigated in ethylene polymerization and copolymerization with methyl acrylate (MA). The catalytic performances were improved by introducing more ortho-substituents. The catalysts exhibited good thermal stabilities at high temperatures, producing branched polyethylenes. The catalysts bearing hydroxyl groups possessing intramolecular H-bonding, resulted in slightly higher incorporation ratios of MA unit when compared with the catalysts bearing methoxyl groups.
摘要:
空间庞大的基于二芳基甲基的配体在后过渡金属催化的烯烃聚合领域中受到越来越多的关注。邻位取代基可对基于二芳基甲基的α-二亚胺Pd催化剂的性能具有显著影响。在这一贡献中,制备了一系列带有邻甲氧基/羟基官能化二二苯甲基单元的α-二亚胺Pd催化剂,characterized,并研究了乙烯聚合和与丙烯酸甲酯(MA)的共聚。通过引入更多的邻位取代基来改善催化性能。催化剂在高温下表现出良好的热稳定性,生产支链聚乙烯。带有羟基的催化剂具有分子内H键,与带有甲氧基的催化剂相比,MA单元的掺入率稍高。