Olefin polymerization and copolymerization catalyzed by dinuclear catalysts having macrocyclic ligands

Abstract

Recently dinuclear complexes have attracted attention as catalysts for olefin polymerization. This account describes the synthesis and catalytic behavior of dinuclear Pd, Ni, Co, and Fe complexes with cyclic ligands. The two metal centers of the dinuclear complexes are located in close proximity owing to the rigid, cyclic ligands. These dinuclear complexes show higher catalytic activity, and/or produce polymers with higher molecular weight than the corresponding mononuclear complexes. The dinuclear catalysts were shown to have higher thermal stability during polymerization. They also enable the synthesis of branched ethylene/acrylate copolymer with acrylate units incorporated into the main chain, and the selective incorporation of non-conjugated dienes in the copolymerization with ethylene, reactions which could not be achieved using their mononuclear analogues.