Hydrogen peroxide, bond order reduction

Osmylation and Epoxidation With osmium tetroxide, carbon nanotubes react as expected for a compound containing double bonds. The osmylation adduct with the respective double bond being replaced by two C-O-bonds is formed as shown in Figure 3.78. However, the process is normally conducted in a photochemical way here. The intermediates thus obtained can be transformed into hydroxylated nanotubes by hydrolysis. In doing so, it is advisable to effect a reoxidation of the resultant osmium(Vl) by hydrogen peroxide in order to minimize the consumption of osmium. The osmylation of carbon nanotubes is reversible so the process may also be employed for purification or separation steps. Contrary to an ozonoly-sis with subsequent reductive work-up, the osmylation does not give rise to holes in the side wall. Hence the electronic structure is less affected. 

After the T S transition in the ion-radical pair (O Fig. 29-2b), an ordinary chemical transformation on the singlet state PES occurs (O Fig. 29-2c). It involves abstraction of hydrogen atom from the N1 atom of FADHj and a proton abstraction from the nearest histidine residue in order to create H2 O2 by reduction of the superoxide anion. This process, accompanied by the formation of hydrogen peroxide, can occur only in the singlet state. The final phase of the catalytic cycle (not shown in O Fig. 29-2) consists of a subsequent proton transfer from FADH ion back to histidine across the system of H-bonds in water-protein chain (Prabhakar et al. 

Addition of carbon radicals to carbon-carbon double bonds is an important reaction that can be carried out under hydrogen transfer conditions [27], Peroxides are usually used as radical precursors and an application of this chemistry is presented in Scheme 3 (Eq. 3.1). More recently, reduction of alkyl radical by C-H hydrogen donor has been examined in order to find an environmentally friendly alternative to tin hydride. Zard has reported a simple and cheap alternative to tin hydride for Barton-McCombie deoxygenation reactions [80]. Heating of xanthates derived from carbohydrates in 2-propanol in the presence of dilauroyl peroxide affords the de-oxygenated products in good yields (Scheme 17, Eq. 17.1). 2-Propanol functions as... 

---