Theory of chemical bonds in metalloenzymes XVI. Oxygen activation by high-valent transition metal ions in native and artificial systems

Theoretical formulation and UB3LYP computational results have been presented for electron transfer reaction between hydroxide anion and high-valent MnO species. Possible roles of Ca(II) and hydrogen bonding to stabilize hydroxide are also discussed in relation to acid-base and radical-coupling mechanisms for water oxidation.