Organocatalytic Microfluidic Double‐Layer Capacitors

TL;DR

This paper introduces a new method for electric-field catalysis using bioinspired structures in microfluidic systems, enabling scalable organic synthesis.

Contribution

The novel contribution is the development of bioinspired supramolecular electrodes that enable scalable electric-field catalysis.

Findings

Supramolecular electrodes based on polyarginine and pyrenebutyrate show high activity for electric-field catalysis.

Electric-field catalysis triples the yield of a well-optimized organocatalytic reaction.

The method overcomes scalability issues of traditional electric-field catalysis.

Abstract

Ideas to use external electric fields to enable, accelerate and direct the movement of electrons during chemical reactions are not new. Theory and experiments under special conditions predict that electric‐field catalysis (EFC) from externally applied fields could change the way we make molecules. The challenge is the incompatibility with organic synthesis under scalable bulk conditions. Access to applied electric fields (AEFs) > 1 V nm−1, predicted as necessary for direct transition‐state stabilization, is not possible even with electromicrofluidic systems, where the distance between the plate electrodes is minimized. Therefore, we decided to shift our attention from the applied fields to their consequences. We consider electrical double layers (EDLs) that form within a few nanometers from the plate electrodes as engineerable supramolecular electrodes. Applying lessons from cell‐penetrating peptides (CPPs), we report supramolecular electrodes with effective electric fields (EEFs) that exceed applied fields by more than five million. According to a proline‐catalyzed aldol condensation installed as benchmark reaction, those engineered from polyarginine and pyrenebutyrate are most active for EFC, exactly as in cellular uptake. With the best supramolecular electrodes, EFC triples the yield of one of the most optimized reactions in organocatalysis. New methods to access scalable EFC open up broad perspectives in organic synthesis and beyond.

Highest expectations from catalysis with external electric fields, from organic synthesis to sustainable industrial production and the origin of life, cannot be explored because of the incompatibility with scalable bulk conditions. This challenge is addressed with bioinspired organocatalytic electrical double‐layer architectures as supramolecular electrodes in microfluidic capacitors. The result is an enabling method for scalable electric‐field catalysis.

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