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Marcus’s theory

Kinetic studies of hexacyanoferrate(III) oxidations have included the much-studied reaction with iodide and oxidation of the TICI2 anion, of hydrazine and hydrazinium, and of phenylhydrazine and 4-bromophenylhydrazine. These last reactions proceed by outer-sphere mechanisms, and conform to Marcus s theory. Catalyzed [Fe(CN)g] oxidations have included chlororuthenium-catalyzed oxidation of cyclohexanol, ruthenium(III)-catalyzed oxidation of 2-aminoethanol and of 3-aminopropanol, ruthenium(VI)-catalyzed oxidation of lactate, tartrate, and glycolate, and osmium(VIII)-catalyzed oxidation of benzyl alcohol and benzylamine. ... [Pg.423]

FIGURE 15. Potential energy surfaces for the ground state DA), the excited state DA, reactant state), and the charge-separated state D+-A, product state), proposed by Marcus s theory. X, total reorganization energy TS, transition state. (Modified from Ref. 19.)... [Pg.23]

Support for this contention of solvent involvement in the proton transfer comes from Marcus s theory (1968). The relationship (11)... [Pg.157]

The final important aspect of Marcus s theory that we would like to mention is the curious square dependence of the activation energy with respect to the free energy of reaction ... [Pg.1039]

An indirect consequence of the considerable interest in Marcus s theory is that, as brilliantly suggested by Marcus himself in 1965, the inverted region is responsible for most chemiluminescent effects. Indeed, as shown in Fig. 36.30, when the Vr and Vp curves intersect with a high activation barrier AG because of the inverted region effect, there may be an electron transfer to a more easily accessible Vp curve. In this case, one of the products is electronically excited and intersects the Vr curve in the normal region with a low activation barrier. [Pg.1040]

To conclude this section, it is important to note that, in its classical form, Marcus s theory only implies two parameters the activation energy to the free energy of the reaction and the reorganization energy. It does not explicitly depend on the importance of the energetic coupling between the initial (reactant) and final (product) state. This effect is explored in the semi-classical Marcus theory [88] and will not be detailed here. [Pg.1041]

Interfadal Electron Transfer. There have been several studies of electron transfer reactions[17, 38]and the connection with Marcus s theory[39]. It may be possible to use a Car-Parrinello like scheme on that part of the system directly affecting the electron transfer. There has also been very interesting studies of the ferro-ferri redox couple in solution[40, 41] that address many issues related to electron transfer from an electrode to a hydrated ion. Slow processes can be treated by transition state methods like the ones used in solid state ionic conducdvity[42]. [Pg.16]

The rate law for exchange between Cr + and the 4-pyridinomethylchromium(iii) cation shows a single path, first order in reactant concentrations. Decomposition in the absence of Cr + occurs therefore at a rate much lower than implied by the current mechanism, which also leads to an impossible rate for the back-reaction between Cr and an organic radical. Marcus s theory has been tested following measurement of the [Cr(bipy)3l+-[Cr(bipy)3] exchange rate in DMF by e.s.r. line-broadening ... [Pg.32]

The classical Marcus s theory is based on the following idea In an electron... [Pg.233]


See other pages where Marcus’s theory is mentioned: [Pg.352]    [Pg.667]    [Pg.191]    [Pg.181]    [Pg.405]    [Pg.187]    [Pg.248]    [Pg.1036]    [Pg.1040]    [Pg.597]    [Pg.25]    [Pg.382]    [Pg.215]    [Pg.215]    [Pg.226]   
See also in sourсe #XX -- [ Pg.215 ]




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