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para-Aminoazobenzenes-Bipolar Redox-Active Molecules
Dominic Schatz1,2, Marcel E Baumert3, Marie C Kersten1,2
1Institute of Organic Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, 35392, Gießen, Germany.
Angewandte Chemie (International Ed. in English)
|June 13, 2024
Summary
Azobenzenes exhibit bipolar redox behavior, acting as both anolytes and catholytes in energy storage. Tailored substitutions enable tunable redox potentials and the first solid-state structure of oxidized azobenzenes was determined.
Area of Science:
- Electrochemistry
- Materials Science
- Organic Chemistry
Background:
- Azobenzenes (ABs) are crucial in energy storage (solar thermal, phase change materials) and battery applications due to their reversible one-electron reduction.
- Standard azobenzene oxidation is irreversible, limiting their use as anolytes.
- 4,4'-diamino substitution enables reversible 2e- oxidation via a stable bis-quinoidal structure.
Purpose of the Study:
- To present a novel azobenzene system demonstrating bipolar redox behavior.
- To explore the potential of azobenzenes as both anolytes and catholytes.
- To investigate the tunability of redox potentials through chemical substitution.
- To characterize the solid-state structure of the oxidized azobenzene form.
Main Methods:
- Synthesis of substituted azobenzene compounds.
- Electrochemical characterization to determine redox potentials and reversibility.
- X-ray diffraction analysis of the oxidized azobenzene species.
Main Results:
- Demonstrated azobenzenes with bipolar redox behavior, functioning as both anolytes and catholytes.
- Showcased tunability of redox potentials via amine and ring substitutions.
- Achieved the first-ever solid-state structural characterization of an oxidized azobenzene form using X-ray diffraction.
Conclusions:
- Azobenzenes can be engineered for bipolar redox activity, expanding their utility in electrochemical energy storage.
- Tunable redox potentials allow for precise application design.
- The structural insights provide a foundation for further development of azobenzene-based energy storage materials.
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