Dioxygen metal activation

This scheme implies that dioxygen is activated only in a secondary step by an intermediate formed in the initial electron transfer reaction between the metal ion and a co-substrate, Si- The reduced form of the metal ion is re-oxidized to its original oxidation state by O2, but such a reaction with a secondary intermediate cannot be excluded. If the rate determining step is Eq. (9), the overall reaction is again zeroth order with respect to dioxygen. 

Conversely, Gourec et al. suggested a mechanism involving a non-metallic active site.85 In the proposed mechanism, based on XPS, SIMS, and CV analysis, dioxygen reacts with protonated nitrogen surface species to form oxidized nitrogen surface species and water. After further reaction with protons and electrons, the oxidized nitrogen is reduced, and water is produced. 

Further work with metal-activated dioxygen is bound to lead to new surprises and new exciting discoveries. 

A. E. Martell, Pure Appl. Chem., 1983, 55, 125 T. G. Spiro, Metal Activation of Dioxygen , Wiley Interscience, New York, 1980. 

The selective oxidation of organic compounds is an area of great interest in the chemical industry.77 Metal activation of dioxygen is frequently used. For example, in the reaction... 

The second hydroxyl group is introduced into the tyrosine side chain through attack by a metal-activated solvent molecule rather than dioxygen. Hydroxide attack at the open para-position yields trUiydroxy phenylalanine (20), which undergoes oxidation by dioxygen to form the mature quinocofactor-containing protein (21) (equation 11). 

Dioxygen activation in transition metal complexes in the light of molecular orbital calculations. R. Boca, Coord. Chem. Rev., 1983, 50,1-72 (245). 

Activation of Dioxygen by Cobalt Group Metal Complexes Claudio Bianchini and Robert W. Zoellner... 

Simandi LI (2003) Advances in catalytic activation of dioxygen by metal complexes. Kluwer, Dordrecht... 

Partial oxidation reactions are usually carried out over transition metal oxides capable of changing their valent state during their interaction with reacting molecules. Naturally, zeolites with their alumina-silicate composition did not prove themselves as good oxidation catalysts. They failed also to serve as efScient catalyst supporters, since transition metals being introduced into the zeolite matrix lose their ability to activate dioxygen [3,4],... 

For the ascending branch of the volcano plot, the term (1/Z + 1) could serve by itself as an effective ORR activity predictor, whereas, for the descending branch, (1/Z + 1) becomes close to unity at 0.85 V, and the exponential factor exp(—A//, /R70, then determines the ORR rate based on the residual interaction of dioxygen with the (excessively) noble metal catalyst surface. 

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