(α-Diimine)palladium catalyzed ethylene polymerization and (co)polymerization with polar comonomers

Abstract

In this review, a recent development of cationic -diimine palladium(II) complexes for ethylene polymerization and copolymerization with polar functionalized comonomers was briefly described. First, the polymerization mechanism for this type of catalysts was discussed. Next, recent advances in ligand design were provided with special focus on the influence of ligand structures on the catalytic polymerization properties. Last, the ethylene homopolymerization and copolymerization with various polar comonomers, especially acrylate and vinyl ethers were summarized. palladium, -diimine, ethylene polymerization, polar comonomer

Palladium‐Catalyzed Ethylene/Methyl Acrylate Co‐Oligomerization: The Effect of a New Nonsymmetrical α‐Diimine with the 1,4‐Diazabutadiene Skeleton

“…Notably, all the ArDAB ligands applied in the ethylene/MA copolymerization are symmetrical molecules that feature the same aryl rings on the iminic N atoms . However, the reason for the peculiar behavior of the phosphine–sulfonate catalysts is attributed to the different natures of the two donor atoms and to their ability to differentiate the two coordination sites trans to them .…”

Precision Chain‐Walking Polymerization of trans‐4‐Octene Catalyzed by α‐Diimine Nickel(II) Catalysts Bearing ortho‐sec‐Phenethyl Groups

“…Over the past two decades, α‐ diimine nickel and palladium complexes have attracted considerable attention in alkene polymerization field owing to the precursory work of Brookhart and co ‐ workers . In combination with a suitable cocatalyst, these complexes showed good activity for ethylene and 1 ‐ alkene polymerizations, to produce highly branched, moderately branched or linear polyolefins because of chain‐walking . The mechanism of chain walking for 1‐alkene polymerization is shown in Scheme .…”

Polymerization of ethylene using a series of binuclear and a mononuclear Ni (II)‐based catalysts

“…1 H NMR (300 MHz, CDCl 3 , δ , ppm): 1.2 (12H, d), 2.7 (2H, q), 6.8 (2H, d), 6.9 (1H, t), 7.1 (2H, d), 7.2 (2H, t), 7.4 (1H, t), 7.7 (2H, t), 8.2 (2H, d), 8.3 (2H, d). C NMR (300 MHz, CDCl 3 , selected resonances δ , ppm): 161.1 (C = N), 24.9, 23.7 (CH(CH 3 ) 2 ), 29.1, 29.6 (CH(Me) 2 ), 160.6 (C = N). MS (EI, m / z ): 416 [M+, 100%].…”

“…Albeit mechanisms of these types of catalysts are still in ambiguous due to complexity of theirs function through the polymerization; however, there is two main supposed structure include cooperation and independent effect of active centers. Distance between the active centers and the presence of weakly basic substituents are two important factors that can control the cooperative effect of metal centers in olefin homo‐ and copolymerization of polar monomers, especially . According to the literatures, multinuclear catalysts have shown various results in comparison to correspond mononuclear catalysts such as both lower and higher catalyst activity, bimodal to wide range molecular weights distribution, isotacticity, and microstructures …”