The first macrocyclic abnormally coordinating tetra-1,2,3-triazole-5-ylidene iron complex: a promising candidate for olefin epoxidation.

The first macrocyclic and abnormally coordinating, mesoionic N -heterocyclic carbene iron complex has been synthesised and characterised via ESI-MS, EA, SC-XRD, CV, NMR and UV/Vis spectroscopy. 13 C-NMR spectroscopy and CV measurements indicate a strong σ-donor ability of the carbene moieties, suggesting an efficient catalytic activity of the iron complex in oxidation reactions. Initial tests in the epoxidation of cis -cyclooctene as a model substrate confirm this assumption.