Short-Chain Branched Polar-Functionalized Linear Polyethylene via “Tandem Catalysis”

Abstract

Cationic PdII complex 1 chelated by an N-fixed phosphine sultam has been synthesized and structurally characterized. Exposure of 1 to ethylene resulted in the formation of short-chain olefins (1-butene: 2-butene: 1-hexene: 1-octene = 86:7:6:1) with a high catalytic activity of 105 molE molPd–1 h–1. By combination of 1 and one of the well-known phosphinesulfonato PdII catalyst precursors 2–5, linear polyethylenes containing methyl, ethyl, and n-butyl branches of up to 100 per 1000 C were generated from the polymerization of ethylene alone in a “tandem catalysis” one-pot approach. In further exploitation of this concept, linear polyethylenes with both various short-chain branches and a choice of different polar functional groups incorporated into the main chain were obtained for the first time from the copolymerization of ethylene and polar vinyl monomers (methyl acrylate, N-isopropylacrylamide, methyl vinyl sulfone, acrylonitrile, ethyl vinyl ether, vinyl acetate, and allyl bromide). All these apolar and p...