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

Abstract

AbstractPhosphine and pyridine groups have been widely employed in various olefin polymerization catalysts. In this contribution, these two moieties are connected using different bridges, and the properties of their corresponding palladium and nickel complexes are investigated. A series of CH2, NH and O bridged phosphine‐pyridine ligands (2‐(diarylphosphino)methyl‐pyridine, 2‐(diarylphosphino)amino‐pyridine, 2‐diarylphosphinito‐pyridine) are synthesized and characterized. For the CH2 bridged ligand, the introduction of a C6F5 substituent leads to the generation of a mixture of diastereomers, which can be separated by column chromatography. Starting with these five phosphine‐pyridine ligands, the corresponding palladium and nickel complexes are prepared and characterized. The bridging moiety (CH2, NH and O), the substituents on the bridge, and the ligand orientations significantly influence the properties of the metal complexes in ethylene oligomerization and cooligomerization reactions. For the palladium complexes, ethylene oligomerization and cooligomerization with some polar comonomers (methyl acrylate, butyl vinyl ether, vinyltrimethoxysilane, allyl acetate and allyl choride) can be realized. For the nickel complexes, ethylene oligomerization followed by Friedel‐Crafts addition of the resulting oligomers to toluene solvent leads to the formation of branched alkylated aromatic materials.