Side-Arm Control in Phosphine-Sulfonate Palladium- and Nickel-Catalyzed Ethylene Polymerization and Copolymerization

Abstract

A series of phosphine-sulfonate ligands bearing various side-arm substituents were designed and prepared. The corresponding Pd(II) complexes [κ 2 -(P,O)-2-(PPhAr)-1-benzenesulfonato]Pd(Me)(dmso) (Pd1, Ar = o-MeO-C 6 H 4 ; Pd2, Ar = o-PhO-C 6 H 4 ; Pd3, Ar = o-(2,6-Me 2 -C 6 H 3 )O-C 6 H 4 ; Pd4, Ar = o-PhSO 2 -C 6 H 4 ) and Ni(II) complexes [κ 2 -(P,O)-2-(PPhAr)-1-benzenesulfonato]-NiPh(PPh 3 ) (Ni1, Ar = o-MeO-C 6 H 4 ; Ni2, Ar = o-PhO-C 6 H 4 ; Ni3, Ar = o-(2,6-Me 2 -C 6 H 3 )O-C 6 H 4 ; Ni4, Ar = o-PhSO 2 -C 6 H 4 ) were prepared and applied in ethylene polymerization and ethylene−polar monomer copolymerization. Catalysts Pd2, Pd3, Ni2, and Ni3 are moderately active in ethylene polymerization (activity up to 8.7 × 10 5 g mol −1 h −1 ), generating polyethylene with high molecular weights (M n up to 105100) and high melting temperatures (T m up to 131.6 °C).The two palladium catalysts can also initiate efficient copolymerization of ethylene with methyl acrylate, allyl cyanide, and allyl acetate. Most importantly, high copolymer molecular weights (M n between 21600 and 82500) and high polar monomer incorporation ratios (between 6.1% and 15.2%) could be achieved simultaneously in this system. This side-arm strategy is highly effective in modulating the properties of the phosphine-sulfonate palladium and nickel catalysts.

Ethylene (co)Oligomerization by Phosphine‐Pyridine Based Palladium and Nickel Catalysts

“…The cooligomers also possess relatively linear structures. For example, the methyl acrylate was incorporated both in the main chain and in the terminal chain end (Figure S59) . No incorporation on the end of branches was observed.…”

Influence of Polyethylene Glycol Unit on Palladium‐ and Nickel‐Catalyzed Ethylene Polymerization and Copolymerization

“…[13] Such short metal-oxygen distances have been previously observed in some Group 10 phosphine-sulfonate complexes. [14] Moreover, during polymerization and after the dissociation of the coordinating DMSO or PPh 3 ,i nteractions that affect the polymerization or copolymerization processes might occur.…”

Single and binary catalyst systems based on nickel and palladium in polymerization of ethylene

“…Initial reports by Brookhart and co‐workers revealed that complexes of nickel and palladium bearing sterically hindered α‐diimine ligands could generate high‐molecular‐weight polymers with high catalytic activity in ethylene polymerization . The properties and reactions of metal complexes are highly dependent on the selection of supporting ligand(s), and this selection is one of the keys to successful coordination chemistry. Late transition metal catalysts based on bulky bis)imine(ligands usually depend on the structures of ligands and ortho ‐position groups on the aryl rings that showed very interesting behaviours in olefin polymerization .…”