Interplay between the Oxygen Reduction Reaction and Atom Transfer Radical Polymerization with Molecular Cu-Based...

Area of Science:

• Coordination Chemistry
• Polymer Chemistry
• Electrochemistry

Background:

• Optimizing copper catalysts is key for advancing polymerization in aerobic conditions.
• Understanding catalyst structure-performance relationships is crucial for electrocatalysis and polymerization.

Purpose of the Study:

• To investigate how ligand modifications in Cu-based catalysts affect their performance in oxygen reduction reactions (ORR), hydrogen peroxide reduction reactions (HPRR), and electrochemically mediated Atom Transfer Radical Polymerization (ATRP).
• To compare the catalytic activity of Cu/tris-(2-pyridylmethyl)amine (TMPA) with Cu catalysts featuring TMPA ligands with electron-donating para-substituents.

Main Methods:

• Synthesis and characterization of Cu/TMPA and para-substituted TMPA catalysts.
• Evaluation of catalytic activity in aqueous ORR and HPRR.
• Assessment of polymerization performance for acrylates and methacrylates using ATRP.

Main Results:

• Para-substitution on TMPA ligands decreased ORR and HPRR activities, reducing O2 consumption compared to Cu/TMPA.
• Para-substituted TMPA catalysts were effective for acrylate polymerization (Mw/Mn < 1.3).
• Methacrylate polymerization with para-substituted TMPA catalysts resulted in high polydispersity (high Mw/Mn) due to excessively high reaction rates.

Conclusions:

• ORR/HPRR and ATRP are competing processes in aqueous aerobic environments.
• Electron-donating para-substituents on TMPA ligands tune the reactivity of Cu catalysts, diverging their performance in ORR/HPRR and ATRP.
• Ligand design is a critical factor for optimizing Cu-based molecular catalysts for simultaneous ATRP and ORR/HPRR applications.