Seminarium "Modeling of Complex Systems"

The development of sustainable catalytic methodologies based on earth-abundant first-row transition metals represents a key challenge in modern chemistry. 1 In this talk, I will present our recent work demonstrating that a single pincer ligand framework can support iron, cobalt, and manganese complexes with remarkably diverse and well-defined catalytic reactivity.Using this versatile platform-pincer ligand- we have explored three distincttransformations across the metal triad (Figure 1). With iron, spin-state-resolved DFTanalysis combined with experimental studies revealed β-hydride elimination as the dominant deactivation pathway in alkene metathesis, and identified design principles to restore productive reaction. 2 With cobalt, two isostructural complexes differing only in their ancillary ligand (N₂ vs. methyl) exhibit orthogonal E/Z stereoselectivity in allyl ether isomerization, arising from fundamentally different mechanisms. 3 With manganese, the same pincer scaffold enables a highly efficient Michael addition ofunactivated aliphatic nitriles to α,β-unsaturated ketones. 4 These three examples illustrate that the choice of metal within the same pincerframework has profound consequences for both the reaction mechanism and the catalytic outcome. Spin-state control, ligand non-innocence, and the stability of key intermediates all play decisive roles, and understanding them is essential for the rational development of earth-abundant metal catalysts.

References:1. Bullock, R. M. et al. Using nature’s blueprint to expand catalysis with Earth-abundant metals. Science 369, eabc3183 (2020).2. Młodzikowska‐Pieńko, K. et al. Toward Iron‐Catalyzed Alkene Metathesis: Mapping the Reactivity and Deactivation Pathways of an Iron Metallacyclobutane. Angew. Chem. 137, e202515731 (2025).3. Garhwal, S. et al. Reversible 1, 2-Methyl Migration to an N-Heterocyclic Carbene in a PCNHCP Cobalt (I) Complex Enables Stereoselective (E and Z) Allyl Ether Isomerization. (2023).4. Dey, K. et al. Manganese‐Ketenimine Intermediates as Active Catalysts in the Michael Addition of Unactivated Nitriles to α, β‐Unsaturated Ketones. Angew. Chem. Int. Ed. 64, e202423275 (2025).