Recent advances in thermally robust, late transition metal‐catalyzed olefin polymerization

Abstract

Olefin polymerization catalysts employing late transition metals, such as Ni, Pd, Fe and Co, have been heavily investigated since their discovery in the mid‐1990s. Despite the advantages and appeal these catalysts have displayed in academic research, their implementation in industry has remained restricted due to a variety of limitations and drawbacks. One specific limitation is the relative thermal instability of most late transition metal olefin polymerization catalysts at the temperatures commonly utilized for industrial polymerizations. This review focuses on the development of Ni‐, Pd‐, Fe‐ and Co‐based olefin polymerization catalysts that display increased thermal stability at super‐ambient reaction temperatures. These advances in thermal stability have been realized using a variety of ligand modifications, and their polymerization activities and thermal stability are summarized herein. Lastly, a brief outlook on the future of thermally stable, late transition metal olefin polymerization catalysts is provided. © 2018 Society of Chemical Industry

A continuing legend: the Brookhart-type α-diimine nickel and palladium catalysts

“…Over the past few years, there have been numerous review articles concerning α-diimine Ni and Pd catalysts, with aspects including the chain walking mechanism, ligand structures, different monomers, and polymer properties. [23][24][25][26][27][28][29][30][31][32] However, there have been some major advances recently concerning catalyst developments, 33 which allowed far greater control over the polymerization process as well as polymer microstructures. Most importantly, the suitable polar monomer substrate scope has been significantly expanded through these catalyst developments.…”

Fusing Carbocycles of Inequivalent Ring Size to a Bis(imino)pyridine-Iron Ethylene Polymerization Catalyst: Distinctive Effects on Activity, PE Molecular Weight, and Dispersity

“…The outstanding productivities attainable by bis(arylimino)pyridine-iron and bis(arylimino)pyridine-cobalt (pre)catalysts (A, Figure 1) for the polymerization of ethylene, initially reported over twenty years ago [1][2][3][4], have spurred a myriad of academic and industrial research disclosures [5][6][7][8][9]. Through systematic variation of the steric and electronic properties of the ligand frame and in particular to the N-aryl groups, catalysts capable of generating highly sought-after materials such as α-olefins, linear PE waxes, and high-density polyethylene (HDPE) are all accessible [2,6,10].…”

“…Through systematic variation of the steric and electronic properties of the ligand frame and in particular to the N-aryl groups, catalysts capable of generating highly sought-after materials such as α-olefins, linear PE waxes, and high-density polyethylene (HDPE) are all accessible [2,6,10]. Moreover, such targeted ligand manipulation has seen remarkable improvements to the temperature stability of the catalyst itself [5][6][7][8][9][11][12][13][14], a limitation often levelled against the first-generation catalysts [4,6]. Elsewhere, other types of neutral N,N,N-ligand skeleton such as N-[(pyridin-2-yl)-methylene]-8-amino-quinolines [15], 2-benzimidazolyl-6-imino-pyridines [16][17][18], 2,8-bis(imino)quinolines [19], and 2-imino-1,10-phenanthrolines [20,21] have witnessed some important developments [6][7][8].…”

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

“…3 Determined by GPC using polystyrene as the standard. 4 Determined by DSC. 5 Octene content determined by 13 C NMR spectroscopy.…”

“…The compound α-diimine has been employed as an important synthetic ligand in the fields of coordination chemistry and olefin polymerization [1][2][3][4]. In the middle 1990s, Brookhart and co-workers reported their landmark research on cationic α-diimine based Ni and Pd catalysts that builds a new era in the olefin polymerization field [5].…”