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Water Marcus analysis

Thermodynamic and kinetic data for methyl transfers in other solvents are not available for us to carry out such an extensive analysis as we have done in water. However, we can construct a number of smaller league tables to see if the Marcus pattern is found in other solvents. [Pg.115]

In fact, transient assembly of H-bonded water files is probably common in enzyme function. In carbonic anhydrase, for example, the rate-limiting step is proton transfer from the active-site Zn2+-OH2 complex to the surface, via a transient, H-bonded water network that conducts H+. Analysis of the relationship between rates and free energies (p K differences) by standard Marcus theory shows that the major contribution to the observed activation barrier is in the work term for assembling the water chain (Ren et al., 1995). [Pg.100]

By using cyclic voltammetry, Schiffrin and coworkers [26, 186, 187, 189] studied electron transfer across the water-1,2-dichloroethane interface between the redox couple FefCNls /Fe(CN)6 in water, and lutetium(III) [186] and tin(IV) [26, 187] diphthalocyanines and bis(pyridine)-me50-tetraphenylporphyrinato-iron(II) or ru-thenium(III) [189] in the organic solvent. An essential advantage of these systems is that none of the reactants or products can cross the interface and interfere with the electron transfer reaction, which could be clearly demonstrated. Owing to a much higher concentration of the aqueous redox couple, the pseudo-first order electron transfer reactions could be analyzed with the help of the Nicholson-Shain theory. However, though they have all appeared to be quasireversible, kinetic analysis was restricted to an evaluation of the apparent standard rate constant o. which was found to be of the order of 10 cm s [186, 189]. Marcus [199] has derived a relationship between the pseudo-first-order rate constant for the reaction (8) and the rate... [Pg.353]

In order to test the (in)correctness of the Marcus solvent model, we have carried out extensive MD simulations of a bond-breaking electron-transfer reaction in water at a platinum electrode. Figure 10a shows the computer simulated potential energy surface obtained by a two dimensional umbrella sampling technique. Analysis of the results in Figure 10a brings to light two important effects of the solvent the Marcus model does not account for. [Pg.45]

Kraut A, Lilis R, Marcus M, et al Neurotoxic effects of solvent exposure on sewage treatment workers. Arch Environ Health 43 263-268,1988 Kukull WA, Larson EB, Bowen JD, et al Solvent exposure as a risk factor for Alzheimer s disease a case-control study. Am J Epidemiol 141 1059-1071, 1995 Labreche FP, Cherry NM, McDonald JC Psychiatric disorders and occupational exposure to solvents. British Journal of Industrial Medicine 49 820-825, 1992 Lagakos SW, Wessen BJ, Zelen M An analysis of contaminated well water and health effects in Woburn, Massachusetts. Journal of the American Statistical Association 81 583-596, 1986... [Pg.222]


See other pages where Water Marcus analysis is mentioned: [Pg.54]    [Pg.76]    [Pg.114]    [Pg.284]    [Pg.50]    [Pg.85]    [Pg.184]    [Pg.241]    [Pg.598]    [Pg.320]    [Pg.104]    [Pg.301]    [Pg.252]   


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Marcus

Water analysis

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