A High-Valent Iron(IV) Peroxo Core Derived from O2

Area of Science:

• Bioinorganic Chemistry
• Catalysis
• Materials Science

Background:

• Dioxygen-tolerant [NiFe] hydrogenases are bifunctional enzymes catalyzing H2 oxidation and O2 reduction.
• Mimicking these complex enzymes with simpler synthetic catalysts is crucial for understanding and improving catalytic processes.

Purpose of the Study:

• To design and synthesize a structurally simplified catalyst that mimics the O2 reduction activity of [NiFe] hydrogenases.
• To investigate the mechanism of O2 reduction using a novel [NiFe]-based catalyst.

Main Methods:

• Synthesis of a new [NiFe]-based complex.
• Electrochemical studies to assess catalytic activity for O2 reduction.
• Structural characterization of reaction intermediates, including X-ray crystallography.

Main Results:

• A novel [NiFe]-based catalyst was successfully synthesized and demonstrated O2 reduction activity.
• The catalyst operates via an O2 adduct intermediate.
• Structural analysis identified the first example of a side-on iron(IV) peroxo complex in such systems.

Conclusions:

• The developed [NiFe] catalyst effectively mimics the O2 reduction function of natural hydrogenases.
• The discovery of the side-on iron(IV) peroxo complex provides new mechanistic insights into O2 activation by metal complexes.