Oxo‐Bridged Polyiron Centers in Biology and Chemistry

The functions of iron in biology are often associated with heme or iron‐sulfur proteins. But dioxygen transport, reduction of ribo‐ to deoxyribonucleotides, acid phosphatase activity, oxidation of methane to methanol, and iron storage are amont the growing list of biological phenomena known or believed to be associated with a newly emerging class of proteins having oxo‐bridged di‐ or polyiron aggregates at their metallic cores. The recognition of these iron–oxo proteins as a separate class has stimulated efforts on the part of inorganic chemists to prepare and characterize model compounds that replicate the physical properties and functions of the polymetallic protein cores. As a consequence, a variety of new oxo‐bridged di‐, tri‐, tetra‐, hexa‐, octa‐, and undecairon aggregates has been synthesized. These novel molecules promise not only to provide insight into the detailed characteristics of the metal centers in iron–oxo proteins, but also to serve as a focal point for preparing new materials, including oxidation catalysts and corrosion inhibitors, for the evolution of new theories to describe their physical properties, for developing new strategies for the treatment of iron‐related disease, and for building links between the chemistry of the biosphere and the geosphere.