Consecutive Ligand-Based Electron Transfer in New Molecular Copper-Based Water Oxidation Catalysts

Area of Science:

• Inorganic Chemistry
• Electrochemistry
• Catalysis

Background:

• Efficient water oxidation to dioxygen is crucial for artificial photosynthesis and solar fuel production.
• First-row transition metal complexes offer cost-effective and tunable alternatives for water oxidation catalysts.

Purpose of the Study:

• To synthesize and characterize a new family of dianionic bpy-amidate ligands for water oxidation catalysis.
• To investigate the catalytic activity and mechanism of a copper complex with these ligands for water oxidation.

Main Methods:

• Synthesis of novel bpy-amidate ligands with redox-active moieties.
• Electrochemical analysis, including cyclic voltammetry, of copper complexes.
• Computational studies (e.g., DFT) to elucidate reaction mechanisms.

Main Results:

• A new family of dianionic bpy-amidate ligands (H2LNn-) was successfully synthesized.
• The copper complex [(L4)Cu]2- exhibited significant electrocatalytic activity for water oxidation at pH 11.6.
• Experimental and computational data indicated an all-ligand-based redox process involving aryl-amide and hydroxido groups.

Conclusions:

• The developed bpy-amidate ligands and their copper complexes are promising for water oxidation catalysis.
• The catalytic mechanism involves redox activity primarily within the ligand framework.
• This work contributes to the design of efficient catalysts for solar water splitting.