A team of researchers from Ruhr University Bochum and the Max-Planck-Institut für Kohlenforschung in Mülheim has developed a new method that uses salt‐based catalysts to selectively produce one mirror image of a molecule; a key advance for applications such as pharmaceutical synthesis. The research, published in Journal of the American Chemical Society can be found here:
Reinhard, D. L., Iniutina, A., Reese, S., Shaw, T., Merten, C., List, B., & Huber, S. M. (2025). Asymmetric Counteranion-Directed Halogen Bonding Catalysis. Journal of the American Chemical Society. https://doi.org/10.1021/jacs.4c18378
In many chemical reactions, chiral molecules form as two mirror images that, despite having the same chemical formula, can exhibit very different biological effects. In medicine, for instance, one mirror image might deliver a beneficial effect while its counterpart could lead to unwanted side effects.
This breakthrough was made possible by the combined efforts of Dominik L. Reinhard, Anna Iniutina, Sven Reese, Tushar Shaw, and Christian Merten, whose dedicated work in experimental design, data analysis, and methodological execution was crucial to the project’s success.
The research builds on a modular catalyst system in which both the cation and anion of a salt actively guide the reaction. The cation initiates the process through the formation of halogen bonds with the substrate, while the anion helps secure the correct molecular orientation. This concerted mechanism allows chemists to obtain a specific chiral product with greater reliability.
“These so-called chiral molecules demonstrate a handedness of sorts,”
explains Professor Stefan Huber who alongside Professor Benjamin List headed the research.
“Halogen bonds are weak bonds formed between the cation and the substrate,”
explains Dominik Reinhard, Ph.D. student from Bochum. For its part, the anion, produced by the Mülheim researchers, ensures the correct handedness of the resultant molecule. He goes onto say:
“The salt is introduced to the relevant substrates in a compatible solvent. The concerted action of the salt components then ensures the desired reaction, during which only the molecule with the desired handedness is formed,”
By combining a wide range of different combinations of cations and anions, the salt-based catalysts can be fine-tuned to suit various chemical reactions. Huber stated:
“What makes this approach so attractive is that, by using salts, we’ve created a modular system,”
Hassan graduated with a Master’s degree in Chemical Engineering from the University of Chester (UK). He currently works as a design engineering consultant for one of the largest engineering firms in the world along with being an associate member of the Institute of Chemical Engineers (IChemE).
