Electron transfer ionic equilibria, effects

The several theoretical and/or simulation methods developed for modelling the solvation phenomena can be applied to the treatment of solvent effects on chemical reactivity. A variety of systems - ranging from small molecules to very large ones, such as biomolecules [236-238], biological membranes [239] and polymers [240] -and problems - mechanism of organic reactions [25, 79, 223, 241-247], chemical reactions in supercritical fluids [216, 248-250], ultrafast spectroscopy [251-255], electrochemical processes [256, 257], proton transfer [74, 75, 231], electron transfer [76, 77, 104, 258-261], charge transfer reactions and complexes [262-264], molecular and ionic spectra and excited states [24, 265-268], solvent-induced polarizability [221, 269], reaction dynamics [28, 78, 270-276], isomerization [110, 277-279], tautomeric equilibrium [280-282], conformational changes [283], dissociation reactions [199, 200, 227], stability [284] - have been treated by these techniques. Some of these... 

Despite the abovementioned quasi-equilibrium character of the cyclic voltam-metric curves, a pronounced hysteresis (i.e., a considerable difference between the anodic and cathodic peak potentials) appears. Slow heterogeneous electron transfer, effects of local rearrangements of polymer chains, slow mutual transformations of various electronic species, a first-order phase transition due to an S-shaped energy diagram (e.g., due to attractive interactions between the electronic and ionic... 

Dithionite is widely employed in biochemistry for the study of electron-transfer proteins, both as a means of preparing the reduced form of the protein and as a kinetic probe into the reactive behavior of the protein. For example, ionic strength effects are used to infer the charge of the reactive site. Indeed, most of the 140 reactions for which 802 rate constants have been reported are for biological molecules [4]. Essentially all of these have relied upon the equilibrium... 

All the models are more complicated than before. One accounts for the breakdown of the Born-Oppenheimer approximation. Another shows the possibility of proton transfer by tunnel effect. We see that the role of the solvent cavity size and electron coupling was no longer negligible. It was shown that the water molecule ionisation and hydrogen bonding polarisation play an important role in the ionic equilibrium of water. 

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