Photocatalytic polymers: new applications of heterogeneous photocatalysts Calum Ferguson 1,2 , Julian Heuer 1 , Rong Li 1 , Katharina Landfester 1 1 Max-Planck Institute for Polymer Research, Germany, 2 University of Birmingham, UK Controlling the outcome of catalytic reactions, by designing the catalytic material, allows highly efficient chemical reactions to be undertaken. Selective catalysis has recently been targeted to efficiently produce high-value products, where both selectivity for reagents and products is required. Nature’s catalysts, enzymes, are often extremely selective, where only one reagent is reacted to produce a distinct product. Here, the physical properties of these macromolecular biomaterials dictate which specific substrate can be transformed. Our research looks to produce synthetic catalytic systems that also utilizes a similar approach to nature to embed some selectivity into the catalytic material. Controlling the local hydrophobicity/hydrophilicity of a catalytic center allowing a greater proximity of a desired substrate to the active center. To achieve this, the location of the active center within a macromolecular structure needs to be precisely controlled. Furthermore, a defined active catalytic center is required, where the reaction will proceed. To achieve this molecular photocatalysts are modified with vinyl groups, and copolymerized into well- defined polymer structures. These photocatalytic polymers were synthesized by RAFT-PISA, which results in self-assembled amphiphilic photocatalytic polymers with a micellar like structure. Here the location of the photocatalyst was differed between the hydrophilic and hydrophobic portion of the polymer. The differences in hydrophobicity/hydrophilicity between these two distinct environments resulted in dramatic changes in reaction rates of different substrates, which could be correlated to the partition coefficient of the substrate. Both reductive and oxidative reactions where investigated with a broad substrate scope to confirm the trends observed. Furthermore, the hydrophobic environment could be further modified by adding a secondary solvent to swell the polymeric micelles. This resulted in vastly different reaction rates and, interestingly, could be used to selectively tune the reaction product. References 1. ACS Appl. Mater. Interfaces2023, 15, 2, 2891–2900
P05
© The Author(s), 2023
Made with FlippingBook Learn more on our blog