writer：Ruiyao Wu, Zhen Niu, Lingyun Huang, Yinxin Yang, Zhu Xia, Weifeng Fan, Quanquan Dai, Chenxi Bai
keywords：1
source：期刊
Issue time：2021年
In this work, a series of oxovanadium complexes bearing ligands (S, E)-(+)-2, 6-dialkyl-N-(2-( (2-(4-isopropyl-4, 5-dihydrooxazol- 2-yl) phenyl)amino)benzylidene)aniline (dialkyl = dimethyl (V1), diethyl (V2), isopropyl (V3) ) have been synthesized and characterized by FTIR spectroscopy and elemental analysis. Moreover, the molecular structure of complexes V2 and V3 were defined by X-ray diffraction. On activation with ethylaluminium sesquichloride (Al2Et3Cl3), these complexes exhibited high activity in ethylene polymerization (up to 1.39 × 107 g molv-1 h-1) and showed excellent thermal stability (up to 60 °C). The obtained polyethylene showed moderate molecular weight (21.9 × 104 to 66.4 × 104 g mol-1), narrow distribution (1.91 to 2.86) and unimodal features. The effect of the substituents on the ligands were also investigated in detail. The compound bearing diisopropyl group showed the highest activity toward ethylene polymerization due to the bimolecular deactivation of the catalyst can be effectively inhibited by the steric hindrance of the ortho-substituent on aniline. The complex V2 with moderate steric hindrance was also evaluated as catalyst for the copolymerization of ethylene with norbornene and showed moderate to high activity.