Although quite a familiar feature in high-valent manganese chemistry, the M2(μ-O)2 diamond core motif has only recently been found in synthetic complexes for M = Cu or Fe. Structural and spectroscopic characterization of these more reactive Cu2(μ-O)2 and Fe2(μ-O)2 compounds has been possible through use of appropriately designed supporting ligands, low-temperature handling methods, and techniques such as electrospray ionization mass spectrometry and X-ray crystallography with area detector instrumentation for rapid data collection. Despite differences in electronic structures that have been revealed through experimental and theoretical studies, Cu2(μ-O)2 and Fe2(μ-O)2 cores exhibit analogously covalent metal-oxo bonding, remarkably congruent Raman and extended X-ray absorption fine structure (EXAFS) signatures, and similar tendencies to abstract hydrogen atoms from substrates. Core isomerization is another common reaction attribute, although different pathways are traversed; for Fe, bridge-to-terminal oxo migration has been discovered, while for Cu, reversible formation of an O-O bond to yield a peroxo isomer has been identified. Our understanding of biocatalysis has been enhanced significantly through the isolation and comprehensive characterization of the Cu2(μ-O)2 and Fe2(μ-O)2 complexes. In particular, it has led to the development of new mechanistic notions about how non-heme multimetal enzymes, such as methane monooxygenases, fatty acid desaturase, and tyrosinase, may function in the activation of dioxygen to catalyze a diverse array of organic transformations.
|Original language||English (US)|
|Number of pages||23|
|Journal||Angewandte Chemie - International Edition|
|State||Published - Apr 2 2002|
- Bioinorganic catalysis
- Metal-oxo complexes
- Oxygen activation