Selectivity by the Clock: Programming Reactivity with Alternating Current Frequency

Area of Science:

• Electrochemistry
• Organic Synthesis
• Catalysis

Background:

• Direct current (DC) electrolysis offers limited control over reaction selectivity due to static redox environments.
• Reactive intermediates in DC electrolysis often undergo undesired side reactions like overoxidation or overreduction.
• Alternating current (AC) electrolysis introduces temporal control via electrode potential modulation.

Purpose of the Study:

• To elucidate the mechanism by which AC electrolysis frequency controls reaction selectivity.
• To demonstrate AC electrolysis's ability to access challenging synthetic pathways.
• To showcase AC electrolysis as a tool for programming chemical reactivity.

Main Methods:

• Utilizing AC electrolysis with varying frequencies to control redox environments.
• Investigating amine oxidation, hydrogen isotope exchange, and catalytic cross-coupling reactions.
• Applying finite-element modeling to correlate electrochemical kinetics with selectivity.

Main Results:

• AC frequency synchronizes electrochemical time scales with chemical step rates, enhancing selectivity.
• Demonstrated selective amine oxidation to α-amino radicals and efficient hydrogen isotope exchange.
• Showcased improved catalyst stability and selectivity in heterogeneous catalysis (e.g., Ag-catalyzed dehalogenation).
• Developed finite-element models to predict and understand AC electrolysis selectivity based on kinetics.

Conclusions:

• AC electrolysis provides precise control over reaction selectivity by synchronizing electrochemical inputs with intrinsic chemical timescales.
• Frequency is a key parameter in AC electrolysis for fine-tuning reaction outcomes.
• AC electrolysis offers a powerful strategy for programming chemical reactivity and advancing electrocatalysis.