Tartrate ions, reactions

The luminol reaction has also been used for the CL determination of organic substances such as penicillins [32] and tartrate ion [30] in pharmaceutical preparations by their inhibitory effect on the luminol-iodine and luminol-periodate-manganese(II)-TEA system, respectively. As can be seen from Table 1, the results were quite satisfactory. In the indirect determination of penicillins by their inhibitory effect on the luminol-iodine system, the stopped-flow technique improves the accuracy and precision of the analytical information obtained, and also the sample throughput [32], Thus, in only 2-3 s one can obtain the whole CL signal-versus-time profile and calculate the three measured parameters formation and... 

Tris (ethylenediamine) cobalt (III) chloride was first prepared by Werner.1 Resolution was effected through the chloride d-tartrate which was obtained by allowing the chloride (1 mol) to react with silver d-tartrate (1 mol). The correct ratio of chloride ion to tartrate ion is important and this has meant that it was necessary to isolate the pure solid chloride, the synthesis of which has been described by Work.2 In the present method the less soluble diastereo-isomer is isolated directly and the expensive and unstable silver d-tartrate is replaced by barium d-tartrate. The addition of activated carbon ensures rapid oxidation of the initial cobalt (II) complex and eliminates small amounts of by-products of the reaction. 

Aldoses reduce Tollens reagent, as we would expect aldehydes to do. They also reduce Fehling s solution, an alkaline solution of cupric ion complexed with tartrate ion (or Benedict s solution, in which complexing is with citrate ion) the deep-blue color of the solution is discharged, and red cuprous oxide precipitates. These reactions are less useful, however, than we might at first have expected. 

Haines et al. investigated the stereoselective formation of bisfethyienediamine)-cobaltflll) complexes containing optically active tartaric acid from a reaction of [Co(C03)(en)2]Cl and S(—)-tartaric acid in water at steam-bath temperature, two optically active complexes, A-[Co(S-C4H40g)(en)2] Cl and A-[Co(S-C4H306)(en ], were isolated by TLC with silica gel. In the former complex, the tartrate ion acts as a bidentate chelate agent with one free carboxylic acid (IV), and in the latter the tartrate is trinegative. 

In experimental work, the need often arises to maintain a predetermined concentration of a given metal ion, a concentration that is not allowed to rise above this level nor fall below it. This situation is met by the use of metal ion buffers which maintain a steady pM just as hydrogen ion buffers maintain a steady pH. With their help, free metal ions are replenished (as they are removed by the reaction) from a reservoir of bound metal complex. The first complexing agents to be used for this purpose were citrate and tartrate ions, but much more application has been found for ethylenediaminetetra-acetic acid (EDTA) (cf. 11.27), diethylenetriaminepenta-acetic acid (DTPA), and nitrilotriacetic acid (NTA). The necessary calculations will be found in Perrin and Dempsey (1974). 

There are many other enantioselective reactions catalyzed by chiral metal complexes. These include complexes of various chiral phosphines, tartrate ion, and others as ligands. Chiral cyclopentadienyl metal complexes (32) also are used. Chiral ligands are not limited to those containing an asjonmetric carbon. [RuCbinap)] " is a catalyst for enantioselective hydrogenation. In some cases such as [Rh(dipamp)] and [Rh(pnnp)] well defined complexes are used. In many cases the reaction is carried out in the presence of a chiral ligand and a metal compound. The reaction involving... 

Zn(C2H5)2 above is one. Other examples include those catalyzed by Ti in the presence of tartrate ion and OsO in the presence of chiral ligands. All of the Group VIII (Groups 8,9, and 10) metals, Cu, Zn, and other transition metals have been used for enantioselective syntheses. Enzymes are usually specific for a particular reaction and a particular substrate. Some of the chiral metal catalysts, such as [RuCbinap)] " as a hydrogenation catalyst, are quite general. 

Destruction of the masking ligand by chemical reaction may be possible, as in the oxidation of EDTA in acid solutions by permanganate or another strong oxidizing agent. Hydrogen peroxide and Cu(II) ion destroy the tartrate complex of aluminum. 

Figure 1 illustrates the complexity of the Cr(III) ion in aqueous solutions. The relative strength of anion displacement of H2O for a select group of species follows the order perchlorate < nitrate < chloride < sulfate < formate < acetate < glycolate < tartrate < citrate < oxalate (12). It is also possible for any anion of this series to displace the anion before it, ie, citrate can displace a coordinated tartrate or sulfate anion. These displacement reactions are kineticaHy slow, however, and several intermediate and combination species are possible before equiUbrium is obtained. 

This colour change can be observed with the ions of Mg, Mn, Zn, Cd, Hg, Pb, Cu, Al, Fe, Ti, Co, Ni, and the Pt metals. To maintain the pH constant (ca 10) a buffer mixture is added, and most of the above metals must be kept in solution with the aid of a weak complexing reagent such as ammonia or tartrate. The cations of Cu, Co, Ni, Al, Fe(III), Ti(IV), and certain of the Pt metals form such stable indicator complexes that the dyestuff can no longer be liberated by adding EDTA direct titration of these ions using solochrome black as indicator is therefore impracticable, and the metallic ions are said to block the indicator. However, with Cu, Co, Ni, and Al a back-titration can be carried out, for the rate of reaction of their EDTA complexes with the indicator is extremely slow and it is possible to titrate the excess of EDTA with standard zinc or magnesium ion solution. 

H. 8-Hydroxyquinaldine (XI). The reactions of 8-hydroxyquinaldine are, in general, similar to 8-hydroxyquinoline described under (C) above, but unlike the latter it does not produce an insoluble complex with aluminium. In acetic acid-acetate solution precipitates are formed with bismuth, cadmium, copper, iron(II) and iron(III), chromium, manganese, nickel, silver, zinc, titanium (Ti02 + ), molybdate, tungstate, and vanadate. The same ions are precipitated in ammoniacal solution with the exception of molybdate, tungstate, and vanadate, but with the addition of lead, calcium, strontium, and magnesium aluminium is not precipitated, but tartrate must be added to prevent the separation of aluminium hydroxide. 

MnP is the most commonly widespread of the class II peroxidases [72, 73], It catalyzes a PLC -dependent oxidation of Mn2+ to Mn3+. The catalytic cycle is initiated by binding of H2O2 or an organic peroxide to the native ferric enzyme and formation of an iron-peroxide complex the Mn3+ ions finally produced after subsequent electron transfers are stabilized via chelation with organic acids like oxalate, malonate, malate, tartrate or lactate [74], The chelates of Mn3+ with carboxylic acids cause one-electron oxidation of various substrates thus, chelates and carboxylic acids can react with each other to form alkyl radicals, which after several reactions result in the production of other radicals. These final radicals are the source of autocataly tic ally produced peroxides and are used by MnP in the absence of H2O2. The versatile oxidative capacity of MnP is apparently due to the chelated Mn3+ ions, which act as diffusible redox-mediator and attacking, non-specifically, phenolic compounds such as biopolymers, milled wood, humic substances and several xenobiotics [72, 75, 76]. 

The BCA method is simpler than the Lowry method and relies on the same redox reaction. The target protein is treated with alkaline cupric sulfate in the presence of tartrate, which results in the reduction of the cupric ion to cuprous by the protein. The cuprous ion is then treated with bicichoninic acid (BCA) and two... 

The stabilizing effect of buffers that have multiple charged species in solution should also be investigated to determine the potential reaction between excipients and API. For example, buffers that use carbonates, citrate, tartrate, and various phosphate salts may precipitate with calcium ions by forming sparingly soluble salts. However, this precipitation is dependent upon the solution pH. Because phosphate can exist in mono-, di-, and tribasic forms, each calcium salt has its own solubility product, and precipitation will only occur when one of the solubility product is exceeded. Calcium ions may also interact or chelate with various amino acids, and other excipients, which may also lower the effective concentration of calcium that is capable of interacting with phosphate ions. Finally, the activity of phosphate ions may be lowered due to interactions with other solution components. 

Reaction of disodium tartrate with silver nitrate at pH S.6 was followed by the change in the absorption spectrum at 216-250 nm. Two complex ions were proposed, Ag(C4H4Oe)- and Ag(C4H406)2, with formation constants log j8i = 2.29 and log / 2 = 4.21 respectively.266... 

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