Gold University of Minnesota M. Skip to main content.University of Minnesota. Home page.
News & Events
Graduate Program
Undergraduate Program
Course Offerings


Research News


Breaking Strong C-H and O-H Bonds with a Diiron(IV) Complex

Recent research from the research group of Professor Larry Que.

In a paper just published in Nature Chemistry (DOI: 10.1038/nchem.162), graduate student Dong Wang in Professor Larry Que’s group reported the electrochemical generation of a (μ-oxo)diiron(IV) complex with a redox potential of +1.50 V vs. ferrocene (> +2 V vs. NHE), making this the complex with the highest FeIV/III potential experimentally determined to date. This project was inspired by the chemistry of the enzyme methane monooxygenase, which converts methane to methanol via a diiron(IV) intermediate called Q. Low-temperature bulk electrolysis of the diiron(III) precursor at very positive applied potentials afforded its two-electron oxidized diiron(IV) form in high yield. This species has been characterized by Mössbauer spectroscopy (by Dr. Audria Stubna and Prof. Eckard Münck of Carnegie Mellon University) and EXAFS analysis (by graduate student Erik Farquhar). Driven by its high redox potential, this species oxidizes cyclohexane and its perdeuterated analog (bond dissociation energies of 99.3 and 100.2 kcal/mol, respectively) to give dehydrogenated products at reaction rates up to 1,000-fold higher than those of previously reported FeIV=O complexes. More surprisingly, this highly reactive complex attacks the strong O-H bonds in tert-butanol (rather than its weaker and more numerous C-H bonds), representing for the first time a new type of reactivity for iron complexes. Illustrated below are the structure of this diiron(IV) complex and its novel reactivity.

The University of Minnesota is an equal opportunity educator and employer.