High-valent nonheme iron-oxo units are proposed as key oxidizing intermediates in many iron dependent oxygenases. The pursuit of catalytically relevant intermediates has attracted attention from inorganic chemists interested in generating small-molecule models of the enzyme active sites. In 2003, well characterized examples of synthetic nonheme oxoiron(IV) compounds appeared in the literature and opened the door for research in the area. The intent of this research is to generate and identify new oxoiron(IV) compounds and to explore their chemistry. By extension, isoelectronic imidoiron(IV) complexes have also been sought for study.

A new series of high-valent iron(IV) species supported by pentadentate N5 ligands has been prepared at room temperature. These systems provide remarkable solution state stability to the high-valent oxoiron(IV) compounds and moderate stability to the analogous imidoiron(IV) complexes. The solution stability of these compounds has allowed their extensive characterization. Examination of these species, which are supported by the same pentadentate ligands, allows for a direct comparison between high-valent iron compounds with different terminal groups.

The oxoiron(IV) compounds have shown impressive reactivity towards hydrocarbons. The discovery of oxidative chemistry is relevant to biological systems, as the results support the proposed role of oxoiron(IV) units as key oxidizing intermediates in enzyme catalytic cycles.