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

Abstract

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

Chromium complexes supported by NNO-tridentate ligands: an unprecedented activity with the requirement of a small amount of MAO

“…2,3 However, the mounting demand for high-value-added polyolefins in recent years has spurred extensive interest in both industry and academia to develop homogeneous metal catalysts for olefin polymerization, [4][5][6][7][8][9][10] which are also beneficial for better understanding the polymerization mechanism and, in turn, are greatly helpful in developing new-generation catalysts with high-performances. [11][12][13] In the past few decades, a series of homogeneous metal catalysts, including metallocene 14 and non-metallocene catalysts, [15][16][17][18][19][20][21] have been developed and applied to synthesize a variety of high-value-added polyolefins, such as polar functionalized polyethylene, [22][23][24][25] ultrahigh molecular weight polyethylene (UHMWPE), 26,27 syndiotactic polypropylene (sPP), 28 syndiotactic polystyrene (sPS), 29 polyolefin elastomers (POE), 30 and cyclic olefin copolymers (COC). 31,32 Although the great successes as mentioned above have been achieved, homogeneous metal catalysts still have many unexpected defects.…”

Synthesis of Ethylene/1-Octene Copolymers with Ultrahigh Molecular Weights by Zr and Hf Complexes Bearing Bidentate NN Ligands with the Camphyl Linker

“…According to previous report, imino-amido tribenzyl Zr complexes were readily prepared through the reaction of α-diimine ligand with ZrBn4 via migratory insertion of one benzyl group into one C=N bond [48]. In this study, ZrCl4 reacted with 4 equivalents of MeMgBr at low temperature (about −40 °C) in toluene to give ZrMe4, which was further used in situ to react with α-diimine ligands to form methyl Zr complexes (Scheme 1) [43,52]. In contrast to previous report [28], the desired imino-amido Zr complexes did not formed and ene-diamido complexes 1-Zr and 2-Zr were exclusively obtained.…”

“…Gao and Wu and coworkers reported α-diimine Ni complexes with the bulky camphyl backbone, which display excellent thermal stability and produce polymers with high molecular weights [40][41][42]. For early transition metal catalysts, a series of α-diimine derivatives including imine-enamide and amide-quinoline have been used to support Zr and Hf complexes [43][44][45][46][47][48][49], but direct modifications of N-aryl substituents or backbones of α-diimine ligands are undeveloped. Inspired by these studies, we report herein the synthesis of Zr and Hf complexes from α-diimine ligands with the bulky camphyl backbone.…”

Copolymerization of Ethylene with Selected Vinyl Monomers Catalyzed by Group 4 Metal and Vanadium Complexes with Multidentate Ligands: A Short Review

“…Amido-trihydroquinoline hafnium complexes Hf-2, Hf-3 and Hf-4 with Ph 3 CB(C 6 F 5 ) 4 as the activator showed both high activity and ability to produce copolymers with high 1-octene content and high molecular weights (224,000-1220,000 g/mol) at high temperature (100 • C). At 1-octene concentration equal to 1 mol/L their activity decreased in the order Hf-2, 16,200 kg/(mol Hf •h) >> Hf-4, 2520 kg/(mol Hf •h) > Hf-3, 2340 kg/(mol Hf •h) and incorporation ability was changed as follows: Hf-2 (15.6 mol%) > Hf-3 (7.8 mol%) > Hf-4 (4.8 mol%), indicating significant substituent steric effect on catalytic properties of hafnium catalysts [42]. Zirconium complex Zr-18 bearing the same ligand as complex Hf-2 was also highly efficient in ethylene/ 1-octene copolymerization (13,500 kg/(mol Zr •h), 12.4 mol%) but the exchange of Hf by Ti (Ti-14) led to catalyst with lower activity and low incorporation ability (2160 kg/(mol Ti •h), 1.7 mol%) [42].…”