The driving force for oxidation

The redox potential of the type 1 Cu(II) in MCOs has been a subject of much examination since pei provides the driving force for oxidation of a given reducing substrate. Also, despite the fact that all type 1 sites possess a 2 His, 1 Cys ligand field, and exhibit essentially the same (quantitatively) 600 nm ScysJrCu charge-transfer... 

The driving forces for oxidative quenching by [EU( J and [MV] " are similar, but the rate constant for quenching by [MV] is lO times greater than for quenching by [EU(aq)] - These rate differences reflect the varying reorganization barriers of the oxi-... 

From Eq. 10.11, it is evident that the formation of corrosion products is dependent on the ratio of the partial pressures and activities of the products and reactants. This relation is analogous to the evaluation of the stability of oxides in CO2-CO atmospheres, except that the driving force for oxide scale stability is proportional to the C02-to-CO partial pressure ratio. The activity for pure metals is often assumed... 

The equilibrium lines for the corrosion products can be used to qualitatively access the tendency for a pure metal to form a corrosion product in a given gaseous environment. If the driving force for oxidation (Pco2-Pco) is above the equilibrium line at a given temperature, then the specific metal would be expected to oxidize. The feasibility of sulfide formation can be evaluated in a sinoilar fashion. 

The driving force for migration is established by the different electrochemical potentials (AU) that exist at the two interfaces of the oxide. In other words, the electrochemical potential at the outer interface is controlled by the dominant redox species present in the electrolyte (e.g. O2). 

The initial step of olefin formation is a nucleophilic addition of the negatively polarized ylide carbon center (see the resonance structure 1 above) to the carbonyl carbon center of an aldehyde or ketone. A betain 8 is thus formed, which can cyclize to give the oxaphosphetane 9 as an intermediate. The latter decomposes to yield a trisubstituted phosphine oxide 4—e.g. triphenylphosphine oxide (with R = Ph) and an alkene 3. The driving force for that reaction is the formation of the strong double bond between phosphorus and oxygen ... 

The process of formation of a passivating oxide film is an anodic one the driving force for its formation is raised by raising the potential anodically... 

When the bicyclic thiirene oxide 180164 is dissolved in excess furan, a single crystalline endo-cycloadduct (182) is formed stereospecifically (equation 71)164. This is the first propellane containing the thiirane oxide moiety. Clearly, the driving force for its formation is the release of the ring strain of the starting fused-ring system 180. In contrast, 18a did not react with furan even under forcing conditions. 

The equilibrium (1) at the electrode surface will lie to the right, i.e. the reduction of O will occur if the electrode potential is set at a value more cathodic than E. Conversely, the oxidation of R would require the potential to be more anodic than F/ . Since the potential range in certain solvents can extend from — 3-0 V to + 3-5 V, the driving force for an oxidation or a reduction is of the order of 3 eV or 260 kJ moR and experience shows that this is sufficient for the oxidation and reduction of most organic compounds, including many which are resistant to chemical redox reagents. For example, the electrochemical oxidation of alkanes and alkenes to carbonium ions is possible in several systems... 

The driving force for the transfer process was the enhanced solubility of Br2 in DCE, ca 40 times greater than that in aqueous solution. To probe the transfer processes, Br2 was recollected in the reverse step at the tip UME, by diffusion-limited reduction to Br . The transfer process was found to be controlled exclusively by diffusion in the aqueous phase, but by employing short switching times, tswitch down to 10 ms, it was possible to put a lower limit on the effective interfacial transfer rate constant of 0.5 cm s . Figure 25 shows typical forward and reverse transients from this set of experiments, presented as current (normalized with respect to the steady-state diffusion-limited current, i(oo), for the oxidation of Br ) versus the inverse square-root of time. 

Non-oxide ceramics such as silicon carbide (SiC), silicon nitride (SijN ), and boron nitride (BN) offer a wide variety of unique physical properties such as high hardness and high structural stability under environmental extremes, as well as varied electronic and optical properties. These advantageous properties provide the driving force for intense research efforts directed toward developing new practical applications for these materials. These efforts occur despite the considerable expense often associated with their initial preparation and subsequent transformation into finished products. 

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