Developments in compartmentalized bimetallic transition metal ethylene polymerization catalysts

• Published in: Coordination chemistry reviews Vol. 372; pp. 101 - 116
• Main Authors: Suo, Hongyi, Solan, Gregory A., Ma, Yanping, Sun, Wen-Hua
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2018
• Subjects: Bimetallic complex; Catalyst; Compartmental ligand; Early transition metal; Ethylene polymerization; Late transition metal; Polyethylene microstructure; Ethylene polymerization; Compartmental ligand; Bimetallic complex; Early transition metal; Late transition metal; Catalyst; Polyethylene microstructure
• ISSN: 0010-8545; 1873-3840
• DOI: 10.1016/j.ccr.2018.06.006

[Display omitted] •Diversity of metal complexes as catalysts in ethylene polymerization.•Particular characteristics of metals affect the resultant polyethylenes.•Bimetallic precatalysts in ethylene homo-/copolymerization.•Different linkers affect catalytic activities.•Metal···metal proximity effects and cooperativity on catalytic performance. Recent progress concerning the application of compartmentalized bimetallic complexes as homogeneous catalysts in ethylene polymerization is reviewed with particular regard to metal-metal combinations based on either early- (Ti, Zr, Hf and V) or late-transition metals (Fe, Co and Ni). The effect of positioning two polymerization-active metal centers in close proximity on catalytic activity, molecular weight, molecular weight distribution and levels of branching are thoroughly documented. Compartmental ligands comprising binding domains consisting of phenoxyimines, ansa-bridged cyclopentadienyl-amides, α-diimines and iminopyridines are described as is their capacity to serve as compatible binucleating supports for homobimetallic and also for the less investigated heterobimetallic counterparts. By comparison with their mononuclear analogues, any synergic properties exhibited by these binuclear catalysts represents an underlying theme to be developed where possible throughout this review.