Oxygen atom transfer, osmium

Osmium tetroxide and permanganate are the textbook examples for the direct addition of the hydroxyl function to double bonds as shown in Scheme 3. They have been rationalized to be feasible because of their large thermodynamic exothermi-cities,30 and the existence of a low-energy pathway discussed in Section 2.1 for the transfer of two oxygen atoms from the metal to the adjacent alkene carbons. 

Osmium and ruthenium in high oxidation states (III, IV, or V) form polypyridine (bpy, phen or tpy) hydroxo and 0x0 complexes, which have a rich redox chemistry [166, 167]. Redox changes are metal-localized and accompanied by reactions of M=0 or M-OH bonds. These complexes are active as electrocatalysts of the oxidation of water to O2, or of CF to CI2, or they can transfer oxygen atoms and oxidize organic substrates like (CH3)2CHOH or C6H5-CH(CH3)2. 

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