Defect-Induced Electron Localization Promotes D₂O Dissociation and Nitrile Adsorption for Deuterated Amines.

Area of Science:

• Electrochemistry
• Materials Science
• Organic Synthesis

Background:

• Electrochemical reductive deuteration of nitriles using deuterium oxide (D2O) is a key method for synthesizing deuterated amines.
• This process is hindered by high overpotentials due to slow D2O dissociation and the stable nitrile triple bond.

Purpose of the Study:

• To design a novel catalyst for efficient electrochemical reductive deuteration of nitriles.
• To synthesize deuterated amine precursors, specifically for Melatonin-d4 (5-methoxytryptamine-d4), with improved efficiency and yield.

Main Methods:

• Development and application of low-coordinated copper (LC-Cu) electrocatalysts.
• Electrochemical reductive deuteration of nitriles using D2O as the deuterium source.
• Comparison of LC-Cu with high-coordinated copper (HC-Cu) to evaluate catalytic performance.

Main Results:

• LC-Cu reduced the overpotential by 100 mV and achieved a 68% yield, which is 4 times higher than HC-Cu.
• LC-Cu facilitates electron enrichment, K+ ion hydration, and polarization, enhancing deuterium supply for nitrile reduction.
• LC-Cu promotes a flat adsorption model for nitriles, accelerating reduction kinetics at lower potentials.

Conclusions:

• Low-coordinated copper is an effective catalyst for electrochemical reductive deuteration of nitriles, overcoming previous limitations.
• The developed method allows for high deuterium incorporation, broad substrate scope, and scalable synthesis.
• Deuterated Melatonin-d4 exhibits enhanced antitumor and antioxidation properties, indicating potential for deuterated pharmaceuticals.