Research Vision
Nature’s catalysts exemplify precision, orchestrating chemical bond dynamics through intricate synergistic interactions that enable selective substrate activation and transformation. This natural ability to foster cooperation and create favorable conditions for bond activation inspires our research. Rather than focusing solely on converting substrates into a single product, we approach catalysts as adaptable systems capable of tuning their activity to produce diverse outcomes under varying conditions.
Our work centers on developing dynamic molecular systems that can facilitate complex bond activations, particularly relevant in energy conversion, where variability in energy supply and feedstock quality demands flexibility. By integrating reaction parameters and examining their interdependencies, we aim to uncover synergies that lead to emergent properties beyond the sum of individual components. These adaptive systems, responsive to their environment, hold the potential to behave as self-regulating catalysts tailored for specific transformations.
This approach not only advances resource efficiency but also lays the foundation for universal catalytic systems. Such catalysts could enable a deeper understanding of how to control diverse chemical processes and unlock the potential to selectively produce various products from a wide array of building blocks.
Figure 1. A schematic representation of the molecular approach to developing dynamic and adaptive systems.
Key Research Achievements
Divergent Bond Activation.
One of our projects explored whether a catalyst could open divergent reaction pathways based on reaction conditions by selectively targeting the intrinsic chemical bonds of a primary functional group (Figure 2).[1] Using aldehydes as a model substrate, we developed an iron-based catalyst system capable of selectively addressing C=O (Figure 2, blue) and C-H (Figure 2, red) to produce nitriles or amides under mild conditions. Mechanistic studies revealed that different active species, such as neutral Fe(III)Br3 or an ion pair [Fe(III)Br4][N(C4H9)4], drive these transformations.
Figure 2. Development of an Iron-based system for divergent bond activations in aldehyde.
Adaptive Catalytic Systems
To develop adaptive platforms, we designed a catalytic system featuring a ligand with a borane arm to create a polarized environment that interacts with a rhodium metal center (Figure 3).[2] This system, tested for the hydrogenation of nitroarenes, demonstrated selective control over reduction levels, producing either fully reduced anilines or hydroxylamines under mild conditions. This approach highlights the potential of adaptive catalysts to manage complex reaction networks selectively.
Figure 3. Adaptive hydrogenation of nitroarenes.
Enhanced Bond Activation
Addressing the challenge of selective C–F bond activation, we developed a cooperative system combining a Rh(DMPE)2H fragment with secondary phosphine oxide (Figure 4).[3]. This system catalyzes the hydrodefluorination of perfluoroarenes with high chemoselectivity. Aside from substrates with electron-withdrawing functional groups, the system showed an exceedingly rare tolerance for electron-donating functionalities and heterocycles. Mechanistic insights revealed a rhodium(I) dihydride and phosphine oxide as key cooperative elements, emphasizing the value of molecular templates in overcoming challenging bond activations.
Figure 4. A cooperative template for enhanced C-F bond activation.
Carbon-Carbon Bond Formation
Focusing on carbon-carbon bond formation, we designed a cobalt-boron catalytic system that synergistically activates aldehydes and (trimethylsilyl)diazomethane.[4] This system efficiently facilitates the insertion of a single carbon atom into the substrate, producing silyl enol ethers under mild conditions while preserving sensitive functional groups (Figure 5). This dual-activation approach represents a significant advance in bond activation and molecular synthesis.
Figure 5. A cooperative [Co/PNB] System for C-C bond formation.
Adaptive Alkyne Semihydrogenation
In our research on alkyne semihydrogenation, we demonstrate the transformative potential of adaptive catalysis to control not only chemo- and regioselectivity but also stereoselectivity (Figure 6).[5] We developed a catalyst with a uniquely engineered ligand environment to optimize hydrogen activation and transfer, enabling the selective synthesis of both cis- and trans-alkenes without additives. Mechanistic studies revealed the crucial role of the solvent in guiding unconventional hydrogenation pathways. Additionally, the catalyst’s exceptional durability over multiple cycles highlights its potential for advancing sustainable chemical processes.
Figure 6. An adaptive Catalyst for alkyne semihydrogenation.
Open Positions
The group of Synergistic Organometallic Catalysis (SynOCat) is always seeking new talented students. Exceptionally qualified applicants are welcome to get in touch with Dr. Werlé at any time (christophe.werle@univ-lorraine.fr). Such inquiries should include a curriculum vitae and a cover letter mentioning eligible fellowship funding agencies to whom you might apply to support your stay in the group. We are more than willing to assist you in the preparation of these applications. In addition, please have two letters of recommendation sent to Dr. Werlé by academic mentors who have previously supervised your work.
[1] B. Chatterjee, S. Jena, V. Chugh, T. Weyhermüller, C. Werlé, ACS Catal. 2021, 11, 7176-7185.
[2] V. Chugh, B. Chatterjee, W. C. Chang, H. H. Cramer, C. Hindemith, H. Randel, T. Weyhermüller, C. Farès, C. Werlé, Angew. Chem., Int. Ed. 2022, 61, e202205515.
[3] W. C. Chang, H. Randel, T. Weyhermüller, A. A. Auer, C. Farès, C. Werlé, Angew. Chem., Int. Ed. 2023, 62, e202219127.
[4] S. Jena, L. Frenzen, V. Chugh, J. Wu, T. Weyhermüller, A. A. Auer, C. Werlé, J. Am. Chem. Soc. 2023, 145, 27922-27932.
[5] V. Chugh, J. Wu, M. Leutzsch, H. Randel, T. Weyhermüller, A. A. Auer, C. Farès, C. Werlé, Chem Catalysis 2024, 4, 101078.
