Recent developments in redox-active olefin polymerization catalysts

Olefin polymerization catalysis is an ever-growing and ever-evolving field that is of strategic importance as scientists continually search for new methods to produce advanced polymeric materials. Polymerization catalysts are routinely used to regulate the incorporation of one or more monomers into a polymer chain, which can in-turn dictate the mechanical properties of the resultant material. If chemists are able to control when, how, and to what extent these monomers are polymerized, they can then selectively tailor materials to any targeted application. Significant efforts have been devoted to the development of advanced catalysts whose reactivity may be modulated in situ to produce a range of polymers varying in both their thermal and mechanical properties. To achieve the goal of catalyst modulation in situ, many scientists have turned to redox-active catalysis as a next-generation tool. This review discusses the recent evolution of redox-active olefin polymerization catalysts, which has extensively focused on the use of palladium and nickel-based catalysts. Furthermore, their ability to modulate catalytic activity, polymer microstructure, and even polyolefin grade will be described. (C) 2018 Elsevier B.V. All rights reserved.