Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Two-Electron Reductants

A voltammogram for the two-electron reduction of M has a half-wave potential of —0.226 V versus the SCE. In the presence of an excess of the ligand L, the following half-wave potentials are recorded... [Pg.530]

The chemistry of the Li—FeS2 system is quite complex. There are at least two steps to the reaction at low discharge rates. The first reaction is an approximately two-electron reduction to a new phase which is a hthiated FeS2 compound. [Pg.535]

Note that flavin coenzymes can carry out either one-electron or two-electron transfers. The succinate dehydrogenase reaction represents a net two-electron reduction of FAD. [Pg.654]

Scheme 10.16 Redox cycle of flavins. The cycle is depicted with a two-electron reduction of flavin by NAD(P)H and two one-electron oxidations. Scheme 10.16 Redox cycle of flavins. The cycle is depicted with a two-electron reduction of flavin by NAD(P)H and two one-electron oxidations.
Two-electron reduction of the quinone provides the hydroquinone 10, which may also be formed by two sequential one-electron reductions. It has also been... [Pg.401]

In polarographic analysis it gives two breaks in the curve, indicating a two electron reduction probably by the eqn ClCH2N02+2e = CH2N02 +CJ- (Ref 5)... [Pg.91]

Bromonitromethane. This article supplements the material in Vol 2, B312-R under Bromo-rnethane and Derivatives CA Registry No 563-70-2. The IR and UV spectra are given in Ref 3. In polarographic analysis a two electron reduction to CH2N02 and Br is indicated (Ref 4). It can be quanty detd by treatment with coned sul-... [Pg.91]

The polarography of sulphones has been fairly extensively studied, sometimes with an analytical bias and sometimes with more theoretical interest. It is generally accepted that a two-electron reduction takes place, to sulphinate ... [Pg.108]

Under different conditions (in aqueous electrolyte) the selectivity of the cleavage reaction may be perturbed by the occurrence51-53 of a dimerization process. Thus, while the major process remains the two-electron reductive pathway, 20% of a dimer (y diketone) may be isolated from the cathodic reduction of PhC0CH2S02CH3. The absence of crosscoupling products when pairs of / -ketosulphones with different reduction potentials are reduced in a mixture may indicate that the dimerization is mainly a simple radical-radical coupling53 and not a nucleophilic substitution. [Pg.1011]

Two-electron reduction of 4,4 -(l,3-propanediyl)bis-(iV-methylpyridinium) dibromide with sodium amalgam affords bis-l,4-dihydropyridine 46 <96CL151>. [Pg.231]

EPR spectra of the native D. africanus Fdlll show an almost isotropic signal centered around g = 2.01 similar to the one observed in proteins containing [3Fe-4S] clusters (72). The temperature dependence of this signal and low-temperature MCD spectra and magnetization properties are identical to the ones reported for D. gigas Fdll (93). Upon one-electron reduction ag = 12 signal develops, characteristic of the [3Fe-4S] state. Two-electron reduction elicits an EPR active species with an axial properties and g-values of 1.93 and 2.05, consistent with the presence of a [4Fe-4S] center. [Pg.376]

The reduced alkyl complexes are reoxidized by O2 to the iron(lll) alkyls. The corresponding diamagnetic phthalocyanine iron(ll) alkyl complexes, rFe(Pc)R), were prepared by two-electron reduction of Fe(Pc) by LiAIFl4 to give [Fe(Pc) (actually the Fe(I) phthalocyanine radical anion) followed by reaction with Mel, Etl or i-PrBr. The methyl compound, [Fe(Pc)CHi] was characterized by X-ray crystallography. ... [Pg.249]

Schneemeyer LF, Wrighton MS (1979) Flat-band potential of n-type semiconducting molybdenum disulfide by cyclic voltammetry of two-electron reductants Interface energetics and the sustained photooxidation of chloride. J Am Chem Soc 101 6496-6500... [Pg.298]

Benzoyl-CoA reductase carries out the two-electron reduction of the aromatic ring dnring the anaerobic degradation of benzoate by Thauera aromatica. This involves two-electron transfer from ferredoxin, and a combination of EPR and Mossbaner spectroscopy showed the presence of three different clusters, while inactivation by oxygen was associated with partial conversion of [4Fe-4S] clnsters to [3Fe-4S] clnsters (Boll et al. 2000). [Pg.290]

The third study has employed 4,6-dinitrobenzofuroxan and as metabolic systems the one-electron reductants NADPHxytochrome P450 reductase and ferredoxin NADP(+) reductase and the two-electron reductants DT-diaphorase and Enterobacter cloacae nitroreductase [239]. The compound is activated either by DT-diaphorase or nitroreductase. [Pg.299]

The formation of long-lived Cd e pairs and of metal atoms which are strongly reducing, offers an explanation for the two-electron reduction of solutes, or to express it in other words, for the intermediate storage of electrons on semiconductor particles. The most interesting two-electron reduction is that of water to form Hj Eq. (23). Figure 12 shows experimental results which strongly indicate that formation occurs... [Pg.135]

However, two-electron reduction occurs fractionally to produce H2O2, which may cause deterioration of the polymer electrolyte membrane or gaskets ... [Pg.330]

Arrhenius Plots of Atapp The value of 4 at a given potential E is determined in the same manner as described in Section 10.2.4. Because the eontribution of two-electron reduction to the production of H2O2 (compared with the overall ORR) was very low, we ean evaluate an apparent rate constant at a constant applied potential from the following equation [Wakabayashi et al., 2005a, b] ... [Pg.332]

Au has recently received less attention than Pt as a supported catalyst because of its lower impact in PEMFC energy conversion technology, since the ORR is dominated by a two-electron reduction process, at what is a high overpotential, in acidic media. Nevertheless, it is an important oxygen reduction catalyst in alkaline media, and, in contrast to Pt, is oxide-free in the potential range where oxygen reduction occurs. [Pg.569]


See other pages where Two-Electron Reductants is mentioned: [Pg.152]    [Pg.152]    [Pg.285]    [Pg.23]    [Pg.29]    [Pg.4]    [Pg.301]    [Pg.399]    [Pg.37]    [Pg.94]    [Pg.92]    [Pg.232]    [Pg.194]    [Pg.196]    [Pg.256]    [Pg.375]    [Pg.388]    [Pg.129]    [Pg.129]    [Pg.237]    [Pg.66]    [Pg.127]    [Pg.286]    [Pg.97]    [Pg.36]    [Pg.532]    [Pg.644]    [Pg.647]    [Pg.653]   


SEARCH



Catalytic Two-Electron Reduction of O2 via MCET and PCET

Electron reductions

Selective Two-electron Reduction

Two- step one-electron reduction

Two-electron reduction

Two-electron reduction

Two-electron reduction pathway

Two-electron reduction process

© 2024 chempedia.info