Boosting the Thermal Stability of α-Diimine Palladium Complexes in Norbornene Polymerization from Construction of Intraligand Hydrogen Bonding and Simultaneous Increasing Axial/Equatorial Bulkiness
Boosting the Thermal Stability of α-Diimine Palladium Complexes in Norbornene Polymerization from Construction of Intraligand Hydrogen Bonding and Simultaneous Increasing Axial/Equatorial Bulkiness
复制标题
通过配体内氢键的构建和同时增加轴向/赤道体积来提高降冰片烯聚合中α-二亚胺钯配合物的热稳定性
DOI：
10.1021/acs.inorgchem.0c03185
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发表时间：
2021-01-27
影响因子：
4.6
通讯作者：
Zhang, Xuequan
中科院分区：
文献类型：
--
作者：
Wang, Xiaohua;Dong, Bo;Zhang, Xuequan
提高α-二亚胺后过渡金属络合物的热稳定性并因此使它们在较高温度下更具活性是非常重要的，但对于烯烃聚合领域是具有挑战性的。在本研究中，公开了一种新的α-二亚胺钯络合物家族，其可以在高温（高达140摄氏度）下促进顺丁烯聚合。由于增加轴向和赤道体积以及配体内H中心点F氢键的存在所引起的构象限制，N-芳基旋转可以被有效地限制，因此避免了活性物种在高温下的失活。在80-140 ℃下，这些络合物可以有效地催化异戊烯均聚，得到高达5.65 × 10（7）g PNB/摩尔Ni/小时的高催化活性和高达37.2 × 10（4）g/mol的高分子量聚合物，其比由不含CF 3的络合物介导的催化体系高上级。此外，这些配合物在极性的5-丁烯-2-羧酸甲酯（NB-COOCH 3）存在下也具有中等的催化活性。
Increasing the thermostability of alpha-diimine late-transition-metal complexes and therefore rendering them more active at higher temperatures is of great importance, yet challenging for the olefin polymerization field. In the present research, a new family of alpha-diimine palladium complexes that can promote norbornene polymerization at high temperatures (up to 140 degrees C) is disclosed. Because of the conformational restriction caused by increasing the axial and equatorial bulkiness as well as the presence of intraligand H center dot center dot center dot F hydrogen bonds, N-aryl rotations can be efficiently restricted, therefore circumventing the deactivation of the active species at high temperatures. At 80-140 degrees C, these complexes can efficiently catalyze norbornene homopolymerizations, giving high catalytic activities up to 5.65 x 10(7) g of PNB per mole Ni per hour and polymers with high molecular weights up to 37.2 x 10(4) g/mol, which are highly superior to catalytic systems mediated by CF3-free complexes. Moreover, these complexes could also afford medium catalytic activities in the presence of polar 5-norbornene-2-carboxylic acid methyl ester (NB-COOCH3).