Electrochemically induced Asymmetry:
from materials to molecules and back
Asymmetry is a very common feature of many systems, objects and molecules, that we use in our daily life. Actually, it is in a majority of cases the absolutely crucial ingredient for conferring a useful property to a system, a prominent example being the chiral nature of pharmaceutically active compounds. Chemists have developed various approaches to generate asymmetry, from the molecular to the macroscopic scale, but are still facing major challenges when exploring efficient alternative physico-chemical concepts for symmetry breaking.
The global aim of the ELECTRA project is to propose so far unexplored and versatile strategies, based on the unconventional use of electrochemical phenomena, to generate asymmetry in chemical systems at different length scales.
Investigating simultaneously wired and wireless electrochemistry will open up unique possibilities for advancing the topic of asymmetry generation in an original and cross-disciplinary way. We will determine the utility of these strategies in the frame of two major challenges that are:
-unconventional detection, separation and synthesis of enantiomers, based, among others, on chiral encoded metal phases, very recently pioneered by us;
-design and characterization of Janus systems with complex structures and reactivity
Carefully designed experiments at the forefront of electrochemical science will first enable us to gain a better understanding of the different mechanisms involved in symmetry breaking. An optimization by exploring new concepts with respect to their efficiency, yield and selectivity is the next step. This will prepare for the choice of the most innovative approaches of symmetry breaking, in view of the numerous highly relevant applications, ranging from analysis to catalysis and energy conversion. Furthermore, due to the interdisciplinary character of asymmetry, the findings of this project will not only have a major impact in various areas of chemistry, but will also be very interesting for physics and biology.
Dissymetrization of semi-conductive particles activated under UV-light illumination
The project relies on the theoretical and experimental know-how that we have accumulated in the group over the last two decades. Our background in physical chemistry, materials science, (bio)electrochemistry, and analytical chemistry is helping us to tackle the various scientific challenges related to this project.
The project is organized around two complementary physico-chemical approaches to break the symmetry of chemical systems, namely wired and wireless electrochemistry.
There are three different challenges in this part of the project .
A) The first major challenge is the optimization of the synthesis of chiral imprinted mesoporous metals. A very difficult task is changing the nature of the metal in order to replace noble metals which we used up to now by cheap non-noble metals. So far we were already able to imprint chiral information into mesoporous nickel electrodes, despite their chemical and mechanical more fragile nature (J. Am.Chem.Soc. 141 (2019) 18870, Front Cover; Press release).
B) A second goal of the project concerns the use of chiral metal matrices for enantioselective separation. We’ve succeeded so far in integrating these metals into microfluidic channels and use these modified channels as intrinsically chiral stationary phases for the microseparation of mixtures of enantiomers (Angew. Chem. Int. Ed. 58 (2019) 3471); Cover; Press release )
C) The third important challenge is to adapt these new materials for enantioselective synthesis and push the enantiomeric excess (% ee) into regions of practical interest. Prochiral molecules can undergo electron transfer in principle anywhere in the metal matrix or at its outer surface and not only in the imprinted cavities. We were able to circumvent this problem by performing the enantioselective synthesis using potential pulses. This strategy turned out to be very successful, allowing us to reach unexpected % ee values of over 90%. Such a selectivity is unprecedented in chiral electrosynthesis and also constitutes a change of paradigm in heterogeneous chiral synthesis (Nature Comm. 8 (2017) 2087; Press release ). Very recently we were also able to optimize the enantiomeric excess by a selective protection concept at the outermost surface of the electrodes based on self-assembled monolayers (Chem. Sci. 13 (2022) 2339) and by improve the stability of the electrodes by extending the approach to metal alloys (Nat. Commun. 12 (2021)1314).
In the frame of this part of the project our objective is to push the limits of the concept of bipolar electrochemistry and the corresponding progress we already made is illustrated by a few highlights.
Light-emitting autonomous Janus swimmer
A very interesting synergy is obtained when combining the wireless powering of Janus objects with chiral recognition. This can lead either to enantioselective actuators (Anal. Chem. 92 (2020) 10042; Chem. Mater. 32 (2020) 10663), enantioselective Light Emitting Diodes (ACS Measurement Science Au 1 ( 2021) 110; Chirality 33 (2021) 841) or even to a dynamic readout of chiral information via the trajectory of autonomous enzyme-driven swimmers (Nat. Chem. 13 (2021) 1241)
Last-but-not-least we could very recently also demonstrate that bipolar electrochemistry is a powerful tool to enhance the efficiency of organic (bio)electrosynthesis (Angew. Chem. Int. Ed. (2022) e202111804; Chem. Commun. 58 (2022) 4312)
- Dr. Mohsen Beladi-Mousavi joined us in March 2021 as a post-doc
- Dr. Ileana Pavel joined us in January 2020 as a post-doc.
- Dr. Ariana Alejandra Villarroel Marquez joined us as a post-doc in January 2020
- Dr Serena Arnaboldi joined us in November 2019 as a post-doc
- Kostia Tieriekhov joined us as a PhD student in November 2019
- Dr. Bhavana Gupta joined us as a post-doc in January 2019
- Dr. Ashwin Ambrose Melvin joined us as a post-doc in October 2018
- Dr. Maciej Mierzwa joined us as a post-doc in October 2018
- Dr. Elena Villani joined us in May 2018 as a post-doc.
- Dr. Gerardo Salinas joined us in March 2018 as a post-doc.
- Paul Chassagne joined us as a PhD student in October 2017.
- Laura Adam joined us as a PhD student in October 2017.
| Enantioselective recognition at a chiral metal surface
Selected publications related to the ERC project (for a full list see here)
Pulsed electroconversion for highly selective enantiomer synthesis
Éditeur: Nature Communications, Issue 8/1, 2017, ISSN 2041-1723
DOI: 10.1038/s41467-017-02190-zHierarchical Multiporous Nickel for Oxygen Evolution Reaction in Alkaline Media
Éditeur: ChemCatChem, Issue 11/24, 2019, Page(s) 5951-5960, ISSN 1867-3880
DOI: 10.1002/cctc.201901509Bipolar Conducting Polymer Crawlers Based on Triple Symmetry Breaking
Éditeur: Advanced Functional Materials, Issue 28/25, 2018, Page(s) 1705825, ISSN 1616-301X
DOI: 10.1002/adfm.201705825Uphill production of dihydrogen by enzymatic oxidation of glucose without an external energy source
Éditeur: Nature Communications, Issue 9/1, 2018, ISSN 2041-1723
DOI: 10.1038/s41467-018-05704-5Chemo‐ and Magnetotaxis of Self‐Propelled Light‐Emitting Chemo‐electronic Swimmers
Éditeur: Angewandte Chemie International Edition, 2020, ISSN 1433-7851
DOI: 10.1002/anie.201915705Wireless Coupling of Conducting Polymer Actuators with Light Emission
Éditeur: ChemPhysChem, Issue 20/7, 2019, Page(s) 941-945, ISSN 1439-4235
DOI: 10.1002/cphc.201900116Wireless Electromechanical Readout of Chemical Information
Éditeur: Journal of the American Chemical Society, Issue 140/45, 2018, Page(s) 15501-15506, ISSN 0002-7863
DOI: 10.1021/jacs.8b10072Potential‐Induced Fine‐Tuning of the Enantioaffinity of Chiral Metal Phases
Éditeur: Angewandte Chemie International Edition, Issue 58/11, 2019, Page(s) 3471-3475, ISSN 1433-7851
DOI: 10.1002/anie.201812057Oscillatory Light‐Emitting Biopolymer Based Janus Microswimmers
Éditeur: Advanced Materials Interfaces, 2020, Page(s) 1902094, ISSN 2196-7350
DOI: 10.1002/admi.201902094Synthesis, Characterization, and Electrochemical Applications of Chiral Imprinted Mesoporous Ni Surfaces
Éditeur: Journal of the American Chemical Society, Issue 141/47, 2019, Page(s) 18870-18876, ISSN 0002-7863
DOI: 10.1021/jacs.9b10507Encoding Chiral Molecular Information in Metal Structures
Éditeur: Chemistry – A European Journal, Issue 26/14, 2020, Page(s) 2993-3003, ISSN 0947-6539
DOI: 10.1002/chem.201904835Chiral platinum–polypyrrole hybrid films as efficient enantioselective actuators
Éditeur: Chemical Communications, Issue 55/73, 2019, Page(s) 10956-10959, ISSN 1359-7345
Quadrifunctional Janus particles (left: theoretical scheme; right: SEM/EDX image of a particle obtained by bipolar electrochemistry)