Impact of Ligand Design on an Iron NHC Epoxidation Catalyst.

An open-chain iron pyridine-NHC framework is expanded utilizing a benzimidazole moiety to deepen the understanding of the impact of electronic variations on iron NHC epoxidation catalysts, especially regarding the stability. The thereby newly obtained iron(II) NHC complex is characterized and employed in olefin epoxidation. It is remarkably temperature tolerant and achieves a TOF of ca.

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 -heterocyclic carbene iron complex has been synthesised and characterised ESI-MS, EA, SC-XRD, CV, NMR and UV/Vis spectroscopy. 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 -cyclooctene as a model substrate confirm this assumption.