Aqueous solutions reactive oxygen species

So, in this work it has been shown that after irradiation of 10 5 M fullerene C60 and fullerene C60-containing composites (A- = 320-580 nm) in aqueous solutions and cell suspensions, the generation of reactive oxygen species is observed, and the rate of their generation increases in the case of introduction of fullerenes C60 to the content of aminopropylaerosyl and anthracenaliminopropylaerosyl. 

Zoller T, Zeller WJ. 2000. Production of reactive oxygen species by phagocytic cells after exposure to glass wool and stone wool fibres - effect of fibre preincubation in aqueous solution. Toxicol Lett 114 1-9. 

A detailed kinetic study on the disproportionation of (49b) in neutral aqueous solutions has been performed recently in relation to the mechanisms of oxidative DNA cleavage promoted by this complex.208 Such Crv oxo complexes are among the few known types of metal complexes that cause oxidative DNA cleavage in the absence of reactive oxygen species.209 The interactions of (49b) or [CrO(salen)]+ with DNA have been studied in detail and several possible mechanisms of these reactions have been proposed (reviewed in 2000-2003).11,13,210 Several mechanistic studies on the reactions of [CrO(salen)]+ and related complexes with organic reductants have been performed in relation to the roles of these complexes in Crm-salen-catalyzed oxo-transfer reactions (Section 4.6.5.8.4).211-215... 

Takahashi, N., N. Ito, N. Mikami, T. Matsuda, and J. Miyamoto. 1988. Identification of reactive oxygen species generated by irradiation of aqueous humic acid solution. J. Pestic. Sci. 13, 429-435. 

Above pH 9, decomposition of ozone to the reactive intermediate, HO, determines the kinetics of ammonia oxidation. Catalysts, such as WO, Pt, Pd, Ir, and Rh, promote the oxidation of dilute aqueous solutions of ammonia at 25°C, only two of the three oxygen atoms of ozone can react, whereas at 75°C, all three atoms react (42). The oxidation of ammonia by ozone depends not only on the pH of the system but also on the presence of other oxidizable species (39,43,44). Because the ozonation rate of organic materials in wastewater is much faster than that of ammonia, oxidation of ammonia does not occur in the presence of ozone-reactive organics. 

In the discussion of the general base catalyzed addition step above (p. 120) the objection was raised that it was difficult to believe that general base catalysis would be necessary for the addition of water to so reactive a species as a protonated ester. An answer to this objection is implicit in the discussion above of the mechanism of hydrolysis of orthoesters. It appears that the protonated orthoester, which would be the initial product of the simple addition of a molecule of water to a protonated ester, is too reactive a species to exist in aqueous solution, and that carbon-oxygen bond-cleavage is concerted with the transfer of the proton to the orthoester. The formation of a protortated orthoester by the addition of a molecule of water to the conjugate acid of an ester will be even less likely, and it seems entirely reasonable, therefore, that the formation of the neutral orthoester, by a general base catalyzed process, should be the favoured mechanism. 

---