SBIC ECR Symposium & Poster Presentation 21st International Conference on Biological Inorganic Chemistry 2025

Expanding the Py5 Toolbox: Functionalized Pentapyridine-based Ligands for Synthetic Iron–Oxido Chemistry (#492)

Doreen Reuter 1 , Jonathan Gutenthaler-Tietze 1 , Lena Daumann 1
  1. Heinrich-Heine-University, Düsseldorf, Germany

Iron-based enzymes play a pivotal role in numerous biological oxidation reactions, often mediated by high-valent iron-oxido species.1-2 Synthetic biomimetic iron complexes have become essential tools in elucidating the underlying mechanisms, providing insight into structure–reactivity relationships and enabling the development of functional model systems.3-4 In particular, pentapyridine-based ligand frameworks have proven effective in stabilizing various iron oxidation states and mimicking non-heme active sites such as those found in taurine dioxygenase (TauD) or ten-eleven translocation (TET) enzymes.5-6

Recently, efforts in our group have focused on diversifying the Py5 ligand framework through targeted functionalization to better modulate the steric and electronic environment around the metal centre. These modifications aim to influence reactivity and enable features such as secondary coordination sphere interactions, which are critical for mimicking enzymatic selectivity and efficiency. As a continuation of this work, we report here the synthesis of a novel, triply functionalized pentapyridine ligand and its corresponding iron(II) complex, [FeII(MeCN)(Py5(OH)2-CH2OH)]2+, and iron(IV) complex, [FeIV(O)(Py5(OH)2-CH2OH)]2+, to further enhance the steric and electronic properties of this ligand class. A structural analysis validates the coordination environment's consistency with other Py5 ligands, reinforcing its potential for future functional studies.

This new complex extends the toolkit of bioinspired iron coordination compounds by introducing additional substitution sites, potentially enabling secondary interactions. Moreover, these sites allow for further modification, such as complex anchoring. Overall, the new addition to the Py5 ligand framework provides a promising platform for future studies on redox reactivity and small-molecule activation in synthetic analogues of non-heme iron enzymes.

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  6. Schmidl, D.; et al. Angew. Chem. 2021, 133.