Electrochemical C-N Bond Formation from CO₂ and Nitrate Using Molecular Catalysis

Area of Science:

• Electrochemistry
• Catalysis
• Organic Synthesis

Background:

• Electrochemical C-N bond formation offers a sustainable route to valuable chemicals like amines and amides.
• Heterogeneous electrocatalysts limit detailed structure-activity relationship studies.
• Molecular electrocatalysts provide tunable platforms for fundamental mechanistic investigations.

Purpose of the Study:

• To develop and investigate a homogeneous molecular electrocatalyst for C-N bond formation.
• To explore the electrochemical conversion of CO2 and small nitrogen-containing molecules into C-N coupled products.
• To elucidate the catalytic mechanism and structure-activity relationships.

Main Methods:

• Utilized a monohydroxy terpyridine nickel complex (NitpyOH) as a homogeneous electrocatalyst.
• Performed electrochemical reactions in an aqueous system.
• Employed in situ spectroscopy, electroanalytical techniques, and computational modeling.

Main Results:

• Achieved formamide production as the major C-N coupled product.
• Obtained a peak Faradaic efficiency of 35% and a partial current density of 0.095 mA cm-2 at -0.69 V vs RHE.
• Established structure-activity correlations and elucidated key mechanistic aspects.

Conclusions:

• Demonstrated the efficacy of the molecular nickel complex for electrochemical C-N bond formation.
• Provided fundamental insights into the catalytic mechanism of formamide production.
• Paved the way for using molecular systems in electrochemical small-molecule cross-coupling reactions.