Control of coordination polymerization behavior by counter-anionic effects

In coordination polymerization chemistry, the most active species are cationic transition metals which bear vacant sites for monomer coordination. The steric and electronic properties around the metal center are strongly related to the polymerization behavior. Thus, the development of the catalyst system mainly represents the design of neutral metal complex precursors, especially the structure of the ligand. On the other hand, the choice of counteranions derived from the cocatalysts sometimes plays a crucial role in the controlled coordination polymerization. Some unusual polymerization behaviors on stereospecificity, activity, and monomer reactivity ratios have been reported by designing the structure of these cocatalysts.The review summarizes these examples of polymerization controlled by cocatalysts. Various cocata-lysts, such as methylaluminoxane (MAO), fluoroarylboranes, and borates with different activation mecha-nisms, are introduced based on their structural analysis and molecular design. Heterogeneous cocatalysts, important for industrial applications, are also mentioned with their various characterization methods. The application of these cocatalysts is discussed, along with the introduction of several techniques evaluating the relationship between cocatalysts and polymerization behavior. Moreover, the counter-anionic effect in the late-transition metal-catalyzed polymerization chemistry, which recently attracted many researchers for its versatile applicability for polar monomers, is reviewed.(c) 2023 Elsevier B.V. All rights reserved.

Automated summary

In coordination polymerization chemistry, cationic transition metals with vacant sites for monomer coordination are the most active species. The polymerization behavior is strongly influenced by the steric and electronic properties around the metal center. The design of neutral metal complex precursors, especially the ligand structure, plays a crucial role in the catalyst system development. Additionally, the choice of counteranions derived from the cocatalysts can significantly impact the controlled coordination polymerization.