Topic
Redox
About: Redox is a research topic. Over the lifetime, 26853 publications have been published within this topic receiving 862368 citations. The topic is also known as: reduction-oxidation & reduction-oxidation reaction.
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TL;DR: The general features of O redox are described with discussion about the role of comparatively ionic (less covalent) 3d metal-oxygen interaction on anion redox in lithium rich cathode materials.
Abstract: Conventional intercalation cathodes for lithium batteries store charge in redox reactions associated with the transition metal cations, e.g., Mn3+/4+ in LiMn2O4, and this limits the energy storage of Li-ion batteries. Compounds such as Li[Li0.2Ni0.2Mn0.6]O2 exhibit a capacity to store charge in excess of the transition metal redox reactions. The additional capacity occurs at and above 4.5 V versus Li+/Li. The capacity at 4.5 V is dominated by oxidation of the O2– anions accounting for ∼0.43 e–/formula unit, with an additional 0.06 e–/formula unit being associated with O loss from the lattice. In contrast, the capacity above 4.5 V is mainly O loss, ∼0.08 e–/formula. The O redox reaction involves the formation of localized hole states on O during charge, which are located on O coordinated by (Mn4+/Li+). The results have been obtained by combining operando electrochemical mass spec on 18O labeled Li[Li0.2Ni0.2Mn0.6]O2 with XANES, soft X-ray spectroscopy, resonant inelastic X-ray spectroscopy, and Raman spect...
259 citations
TL;DR: The mechanistic connections among propane oxidative dehydrogenation (ODH) rates, H2 reduction rates, and the electronic transitions responsible for the absorption edge in the electronic spectra of dispersed metal oxides were explored for VOx, MoOx, W O x, and NbOx samples consisting predominately of two-dimensional oxide domains supported on Al2O3, ZrO2 and MgO as mentioned in this paper.
258 citations
TL;DR: In this article, a shallow aquifer was studied for Fe-oxide reduction, sulfate reduction, and methanogenesis, with the main focus on sulfate reducing, and the results showed that the resulting sulfide forms framboidal pyrite via a FeS precursor, with elemental sulfur as an intermediate.
258 citations
TL;DR: In this paper, the redox potentials of ferrocene and decamethylferrocene were measured using the saturated calomel electrode (SCE), showing that the E1/2 value of 1 was more solvent dependent than those of 24.
Abstract: Measurement of the redox potentials (E1/2) of ferrocene (1), decamethylferrocene (2), decamethylcobaltocene (3), and [FeICp*(η6-C6Me6)] (4) (Cp* = η5-C5Me5) in DMF, CH3CN, THF, DME, CH2Cl2, and DMSO were recorded vs. the saturated calomel electrode (SCE), showing that the E1/2 value of 1 was more solvent dependent than those of 24, and that the difference in E1/2 values among 24 was solvent independent, unlike those found between 1 and 24. This shows that 24 are much more reliable internal references for determining redox potentials than 1, but using data from this article, one can convert the literature values reported vs. 1 into values vs. 2, 3, or 4. The electrochemistry of 1 and 2 is all the more inhibited by polyamine dendrimers as the dendrimer generation is higher. On the other hand, ferrocenes or other iron sandwich compounds containing hydroxy groups can reestablish reversible cyclic voltammograms. It is shown, using a tetra(ferrocenylmethylamine), that this phenomenon is due to hydrogen bond...
258 citations
TL;DR: It is shown here that the presence of both an iodido ligand and a σ-donor/π-acceptor phenylazopyridine ligand confers remarkable inertness toward ligand substitution on the half-sandwich ruthenium arene complexes, which are highly cytotoxic to human ovarian A2780 and human lung A549 cancer cells.
Abstract: Organometallic complexes offer chemistry that is not accessible to purely organic molecules and, hence, potentially new mechanisms of drug action We show here that the presence of both an iodido ligand and a σ-donor/π-acceptor phenylazopyridine ligand confers remarkable inertness toward ligand substitution on the half-sandwich “piano-stool” ruthenium arene complexes [(η6-arene)Ru(azpy)I]+ (where arene = p-cymene or biphenyl, and azpy = N,N-dimethylphenyl- or hydroxyphenyl-azopyridine) in aqueous solution Surprisingly, despite this inertness, these complexes are highly cytotoxic to human ovarian A2780 and human lung A549 cancer cells Fluorescence-trapping experiments in A549 cells suggest that the cytotoxicity arises from an increase in reactive oxygen species Redox activity of these azopyridine RuII complexes was confirmed by electrochemical measurements The first one-electron reduction step (half-wave potential −02 to −04 V) is assignable to reduction of the azo group of the ligand In contrast, the unbound azopyridine ligands are not readily reduced Intriguingly the ruthenium complex acted as a catalyst in reactions with the tripeptide glutathione (γ-l-Glu-l-Cys-Gly), a strong reducing agent present in cells at millimolar concentrations; millimolar amounts of glutathione were oxidized to glutathione disulfide in the presence of micromolar ruthenium concentrations A redox cycle involving glutathione attack on the azo bond of coordinated azopyridine is proposed Such ligand-based redox reactions provide new concepts for the design of catalytic drugs
257 citations