Synthesis, characterization and application of iron N-substituted imidazole complexes with the motif ClFeL4OFeCl3

• Iron(III) complexes with different N-substituted imidazole ligands were synthesized.
• Different geometries (octahedral vs tetrahedral) for the iron centers were observed.
• The two iron(III) centers are bridged by an oxido ligand.
• The iron complexes were applied as precatalysts in catalytic epoxidation reactions.

The activation of molecular oxygen was investigated applying a mixture of iron(II) chloride and N-substituted imidazole ligands. The resulting complexes were characterized and investigated by various techniques, pointing out bimetallic complexes with the general Cl(imidazole)4FeOFeCl3 motif. The complexes contain two different iron centers, on the one hand iron with an octahedral geometry and on the other hand iron with a tetrahedral geometry were observed. Both units are connected via a bridging oxido-ligand. Moreover, the complexes have been applied as precatalyst in iron-catalyzed epoxidation of stilbene.

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