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Tautomerizable Flavin Ligands for Constructing Primary and Secondary Coordination Spheres
Neetu Singh1, Haneul Im1, Seongyeon Kwon2
1Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.
Inorganic Chemistry
|November 5, 2025
Summary
Researchers developed a novel flavin-derived ligand for metal coordination, enabling tunable reactivity. This bioinspired approach repurposes flavins for advanced coordination chemistry and organometallic applications.
Area of Science:
- Bioinorganic Chemistry
- Organometallic Chemistry
- Coordination Chemistry
Background:
- Flavins are essential organic cofactors mediating biological electron and proton transfers.
- Their heterocyclic (iso)alloxazine core exhibits unique electro- and photochemical properties.
- Hydrogen bonding interactions are crucial for flavin's biological function.
Purpose of the Study:
- To develop a redox-active, flavin-derived bidentate ligand for organometallic applications.
- To explore the coordination chemistry of the flavin ligand with Fe(II) centers.
- To investigate the redox-responsive and tautomerization behavior of the flavin ligand.
Main Methods:
- Synthesis of a flavin-derived bidentate ligand (allLH).
- Coordination of the ligand with Fe(II) to form octahedral complexes.
- Characterization of complexes using spectroscopic and crystallographic methods.
- Investigation of ligand tautomerization triggered by deprotonation and redox agents.
Main Results:
- Formation of Fe(II) complexes stabilized by outer-sphere hydrogen bonds.
- Observation of ligand tautomerization to the isoalloxazine form upon deprotonation.
- Demonstration of redox-responsive ligand tautomerization using cobaltocene.
- Successful repurposing of flavin as a multifunctional ligand platform.
Conclusions:
- A novel flavin-derived ligand enables the construction of tunable coordination environments.
- The ligand exhibits responsive tautomerization and hydrogen bonding capabilities.
- This work opens new avenues in ligand design and bioinspired organometallic chemistry.
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