Development of Group 4 Metal Complexes Bearing Fused-Ring Amido-Trihydroquinoline Ligands with Improved High-Temperature Catalytic Performance toward Olefin (Co)polymerization

作者：Binghao Han, Yongxin Liu, Chunyu Feng, Shaofeng Liu, Zhibo Li · 发表于：Organometallics · 年份：2021 · DOI：10.1021/acs.organomet.0c00739 · 被引用次数：37 · 研究领域：Organometallic Complex Synthesis and Catalysis、Carbon dioxide utilization in catalysis、Synthetic Organic Chemistry Methods

The development of homogeneous metal catalysts with high activity and high thermal stability is vital for the synthesis of polyolefin elastomers (POEs) in solution-phase olefin polymerization processes. In this contribution, the stoichiometric reactions of 8-(2,6-(R 1 ) 2 -4-R 2 -anilide)-5,6,7-trihydroquinoline ( 1 – 3; 1, R 1 = i Pr, R 2 = H; 2, R 1 = Me, R 2 = H; 3, R 1 = Me, R 2 = Me) with MMe 4 (M = Hf, Zr) afforded metal complexes 1-HfMe 3, 2-HfMe 3, 3-HfMe 3, and 1-ZrMe 3 in high yields. Treatment of ligand 1 with Ti(NMe 2 ) 4 resulted in the formation of 1-Ti(NMe 2 ) 3, which reacted with SiMe 2 Cl 2 to form 1-TiCl 3 . 1-TiMe 3 was obtained by alkylation of 1-TiCl 3 with MeMgBr. All metal complexes were characterized by 1 H and 13 C NMR spectroscopy, and the molecular structures of complexes 1-HfMe 3, 2-HfMe 3, 1-ZrMe 3, and 1-TiMe 3 were determined by single-crystal X-ray diffraction, revealing an approximate trigonal-bipyramidal geometry around the metal center in all of the structures. The complexes showed extremely high activity toward ethylene polymerization (up to 13860 kg of PE (mol of M) −1 h –1 ) and ethylene/1-octene copolymerization (up to 49000 kg of PE (mol of M) −1 h –1 ) at elevated temperatures (up to 140 °C). The catalytic properties were highly dependent on the appropriate matching of the metal and cocatalyst. In the presence of [Ph 3 C][B(C 6 F 5 ) 4 ], the activity of metal complexes with the same ligand was in the order Hf > Zr > Ti; with B(C 6 F ...