Redox agents

The Ag - K2S2O8 is also a very useful redox agent and the following mechanism for its decomposition was proposed by Bawn and Margarison [40]. 

For chromatographic sorbents it is necessary that the polymeric cover be uniformly distributed over the silica surface and chemically coupled to it. The appropriate introduction of the initiator is one of the decisive steps of this task. The first method (binding to the surface) increases the yield of grafted polymer. However in this case a large amount of homopolymer is formed. This disadvantage could be prevented by the application of hydroperoxide initiators in combination with the proper redox-agents [78-81],... 

A final class of multifunctional initiators is based on the use a (muUi)functional polymer and a low molecular weight redox agent. Radicals on the polymer chain arc generated from the polymer bound functionality by a redox reaction. Ideally, no free initiating species are formed. The best known of this class are the polyol-redox and related systems. Polymers containing hydroxy or glycol and related functionality are subject to one electron oxidation by species such as ceric ions or periodate (Scheme 7.23).266,267 Substrates such as cellulose,... 

The results given here suggest that, though Eq. (3) is simple, the relation involved in the equation might be very important to elucidate the membrane transport phenomena under a membrane potential applied not only by an external electric source but also by chemicals such as redox agents. 

Together with active metal electrodes, the membrane electrodes represent the best known ion-selective electrodes (ISEs) however, the membrane type has the advantages of insensitivity to redox agents and surface poisons. As the... 

Anions play key roles in chemical and biological processes. Many anions act as nucleophiles, bases, redox agents or phase transfer catalysts. Most enzymes bind anions as either substrates or cofactors. The chloride ion is of special interest because it is crucial in several phases of human biology and in disease regulation. Moreover, it is of great interest to detect anionic pollutants such as nitrates and phosphates in ground water. Design of selective anion molecular sensors with optical or electrochemical detection is thus of major interest, however it has received much less attention than molecular sensors for cations. 

Tables 1 and 2 show a series of commercially available redox agents covering a wide range of redox potentials. A more complete picture is available in literature.2...

From a practical viewpoint, the choice of the most appropriate redox agent follows the same criteria applied to the choice of the working potential in controlled potential electrolysis. The redox agent must possess a standard electrode potential 100-200 mV more positive... 

The Fe-S clusters are believed to act as electron transfer centres for external redox agents such as cytochrome c3 (the high electron transfer ability of metal-sulfur clusters has been discussed in Chapter 8, Section 1, whereas the redox aptitude of cytochromes will be considered in... 

This oxidation state has usually a transitory existence. It may be generated by electrochemical, photolytic and thermal non-complementary reactions using a le redox agent... 

So what does riboflavin do As such riboflavin does nothing. Like thiamine, riboflavin must undergo metabolic change to become effective as a coenzyme. It fact, it undergoes two reactions. The first converts riboflavin to riboflavin-5-phosphate (commonly known as flavin adenine mononucleotide, FMN), about which we will say no more, and the second converts it to flavin adenine dinucleotide, FAD. The flavins are a class of redox agents of very general importance in biochemistry. FAD is the oxidized form and FADH2 is the reduced form. ... 

Aromatic amines Redox Clays (review) In presence of metal ions that are good redox agents... 

Roles that are normally associated with metals as Lewis acids and as redox agents [4,5], can be emulated by organic compounds. This review will introduce the reader to the research field of Lewis acid organocatalysts. This field, compared to other types of organocatalysts, which are highlighted in the other chapters of this volume, is still limited. The number of asymmetric catalyzed examples is small, and the obtained enantiomeric excess is sometimes low. Therefore, this review will also cover a number of reactions promoted by achiral catalysts. Nevertheless, due to the broad variety of possible reactions, which are catalyzed by Lewis acids, this research field possesses a large potential. 

Thio, L. L. and Zhang, H. X. (2006). Modulation of inhibitory glycine receptors in cultured embryonic mouse hippcampal neurons by zinc, thiol containing redox agents and carno-sine. Neuroscience 139, 1315-1327. 

A third way of indirect electrolysis is given, if the redox agent which is activated electrochemically, is fixed at the electrode surface and is regenerated there continuously after reaction with the substrate. In this case a separation step is unnecessary (see Fig. 4). 

Such an activation of the electrode surface can, on the one hand, take place in situ by the continuous formation of the active redox agent on the electrode surface during the electrolysis. This is valid, for example, for the nickel(III)oxide hydroxide electrode which is spontaneously formed during anodic polarization of a... 

Table 1. Standard redox potentials of some inorganic redox agents "...

Tremendous effects have been made in studying the possibilities for the electrochemical generation and regeneration of inorganic redox agents like Cr(VI) V(V), Mn(III) Ce(IV) , and Co(in) and their application in the oxidation of aromatics. These studies are mainly performed by means of three types of reactions side-chain oxidations to form benzaldehydes, side-chain oxidations to generate benzoic acids, and nuclear oxidations for the synthesis of quinones (Scheme 1). 

Electro-generated chromium(II) is also very effective in the pinacolization of otherwise unsatisfactory dimerizing carbonyl compounds (Table 5, No. 13)220-222) this case the chromium(II) ion does not act as redox agent but catalyzes the formation of a chromium(III) complex of the carbonyl compound which subsequently is reduced to the pinacol directly at the cathode (Eqs. (73)-(77)). 

Iron and its compounds are environmentally acceptable redox agents that are finding increased use in remediating toxic waste in groundwaters 1... 

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