Electronic structures and reactions of metal-oxos

The dianionic oxo ligand occupies a very special place in coordination chem., owing to its ability to donate pi electrons to stabilize high oxidn. states of metals. The ligand field theory of multiple bonding in metal-oxos, which was formulated over 50 years ago, predicts that there must be an "oxo wall" between Fe-Ru-Os and Co- Rh-Ir in the periodic table. After reviewing early work, I will discuss the electronic structures of metal-oxo complexes that catalyze hydrocarbon oxygenation and water oxidn. reactions. In the latter area, work in my lab by Bryan Hunter and Astrid Mueller has shown that water oxidn. to dioxygen catalyzed by mixed-metal layered double hydroxides likely involves high-valent Fe-oxo intermediates.