Redox natural

The equation is balanced. Although we could have balanced this equation by inspection, the detailed procedure reveals its redox nature. 

Another situation is observed when salts or transition metal complexes are added to an alcohol (primary or secondary) or alkylamine subjected to oxidation in this case, a prolonged retardation of the initiated oxidation occurs, owing to repeated chain termination. This was discovered for the first time in the study of cyclohexanol oxidation in the presence of copper salt [49]. Copper and manganese ions also exert an inhibiting effect on the initiated oxidation of 1,2-cyclohexadiene [12], aliphatic amines [19], and 1,2-disubstituted ethenes [13]. This is accounted for, first, by the dual redox nature of the peroxyl radicals H02, >C(0H)02 and >C(NHR)02 , and, second, for the ability of ions and complexes of transition metals to accept and release an electron when they are in an higher- and lower-valence state. 

In addition to the reactions discussed in the present section, specific reactions caused by the presence of some excipients may occur in solids. A detailed overview would be beyond the scope of this work, and we will simply present here two non-redox breakdown reactions that involve reducing sugars (i.e., sugars that contain an aldehyde function). The two reactions, however, are of a non-redox nature in that the aldehyde group does not act as a reducing reagent. 

Transition metal oxides attract great interests mainly due to their redox nature, which is thought to be related with their flexible stmcture modiflcation under reductive and oxidative conditions. Such stmcture modiflcation takes place by forming so called crystallographic shear (CS) stmctures to accommodate anion vacancies in speciflc crystallographic planes by simultaneous shear displacement and crystal stmctural collapse [30-32]. High-resolution transmission electron microscopy (HRTEM) is a... 

An important attribute of these materials comes from the two distinct cationic sites (Oh and Td), and the feasibility of cations migration among them due to the redox nature of metalions, while keeping the spinel structure intact. This particular aspect helps to avoid possible segregation/sintering of metal-ions and remain stable for longer period, compared to a mixed metal oxide catalyst. This unique property of spinels makes them an attractive candidate for number of catalytic reactions. 

Wade expanded the 1971 hypothesis to incorporate metal hydrocarbon 7T complexes, electron-rich aromatic ring systems, and aspects of transition metal cluster compounds [a parallel that had previously been noted by Corbett 19) for cationic bismuth clusters]. Rudolph and Pretzer chose to emphasize the redox nature of the closo, nido, and arachno interconversions within a given size framework, and based the attendant opening of the deltahedron after reduction (diagonally downward from left to right in Fig. 1) on first- and second-order Jahn-Teller distortions 115, 123). Rudolph and Pretzer have also successfully utilized the author s approach to predict the most stable configuration of SB9H9 (1-25) 115) and other thiaboranes. 

A new method for the preparation of pyrrolo[2,l-c][l,4]benzothiazepine 292 starting from aldehyde 291 with an intramolecular Mitsunobu cyclization in the last step has been reported (Scheme 63 (1999T1479)). A disadvantage of this procedure is the redox nature of the Mitsunobu reaction, which is responsible for a side oxidation of the thiol group and poor isolated yields of the product. 

Peracids such as m-chloroperbenzoic acid (MCPBA) clearly illustrate the redox nature of oxidative addition. In this reaction the olefin is oxidized and the MCPBA is reduced to meta-chlorobenzoic acid, which precipitates slowly from solution. 

Acetylene hydratase [74] is unique among the molybdenum and tungsten enzymes. This enzyme catalyzes the hydration of an unsaturated organic substrate, acetylene, a reaction that is neither an oxidation nor a reduction. Although tungsten may assume different oxidation states, the non-redox nature of the sub-... 

Truly, the redox reaction concept in its simplest form, transfer of one or several electrons between two species, is much easier to apply to the central atoms of inorganic complexes and relatively simple covalent inorganic compounds with their well-defined oxidation states than to the carbon atoms of organic molecules. Nevertheless oxidation states of the latter can be defined using very simple rules (see, e.g. Hendrickson et al., 1970) and immediately reveal the possible redox nature of any transformation at a carbon atom. It is also true that redox mechanisms other than electron transfer—hydrogen atom or hydride transfer, oxygen transfer, displacement, etc.—should by their very... 

Some of the oxides of vanadium and molybdenum catalyze the selective oxidation of hydrocarbons to produce valuable chemical intermediates. In a reaction path proposed by Mars and van Krevelen (see Section 10.5), the hydrocarbon first reduces the surface of the metal oxide catalyst by reaction with lattice oxygen atoms. The resulting surface vacancies are subsequently re-oxidized by gaseous O2. The elementary steps of this process are shown below. Electrons are added to the sequence to illustrate the redox nature of this reaction. 

Tetravalent manganese is not soluble in acids it must be reduced to the divalent state in order to dissolve. Hydrochloric acid is a useful reductant for this purpose, and in the process, a stoichiometric amount of chloride is oxidized to chlorine gas. The evolution of this gas is indicative of the redox nature of the reaction. 

Because of the redox nature of the NOS multienzyme complex, studies have been extended to heavy and transition metals. In one of our recent studies, we investigated the effects of heavy and transition metals on cNOS activity (Mittal et al., 1995). When brain cytosolic preparations were prein-... 

Kitagawa, T., Toyoda, J., Nakasuji, K., Yamamoto, H., Murata, I. (1990). Amphoteric redox nature of p-benzoquinones with donor- and aceeptor-substittients. Chemistry Letters, pp. 897,... 

Since the discovery of the redox nature of conjugated polymers doping, various electrochemical techniques have been used, both to carry out the doping reaction and to characterize the doped polymer. 

The redox nature of the reaction is revealed by the production of electrons, and the acid-base nature of the reaction by the production of H". Sloping boundaries separate stability fields that involve a change in acidity (H or OH concentration) and a change in oxidation state (e transfer). 

The redox nature of co-ordination complexes with macrocyclic ligands has been examined using the trans- A-d CD system. The electrolytic reduction of the copper(n) complex of macrocyclic 8chiflf bases of the type trans- A d QnQ (or tet-a) yields the highly reactive yellow cuprous complex... 

The redox nature of palladium(ii) salts has been investigated, methods being described for the study of the rates of oxidation of olefins. The reduction of benzoquinone by 7r-allylpalladium chloride in aqueous hydrochloric acid solutions has also been reported. ... 

The transient kinetic model of the standard SCR reaction over a commercial V-based catalyst for vehicles reported in Reference (101) is the only treatment available so far accounting both for the redox nature of the SCR catalytic mechanism and for the ammonia inhibition effect. It relies on a dual-site redox scheme, whereby ammonia is first adsorbed onto acidic sites, but reacts with NO on different redox sites associated with the vanadium component. The redox sites can, however, be blocked by excess ammonia. Adopting a Mars-Van Krevelen formal approach, the following modified redox (MR) rate expression was derived (27) ... 

Mod d Redox Kinetics (MR)— In order to take into account the redox nature of the Standard SCR reaction and the observed transient features indicating an ammonia inhibition effect, a new kinetic model was derived. 

Several metal oxides with varying phase structures and nanostructures have been developed, including manganese oxide, iron oxide, molybdenum oxide, tin oxide, and titanium oxide. The most prominent issues surrounding transition metal oxide development efforts are (1) limited electronic conductivity and low theoretical capacitance in comparison to ruthenium oxide and (2) poor cyclability due to their redox nature and electrochemical instabilities. The varying electrochemically stable potential windows for some species of metal oxides completely eliminate their potential applications in ES devices. 

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