Ascorbate, reduction with

Acetate, (reduction with) ascorbic acid + KI, citrate, V,V-dihydroxyethylglycine, EDTA, F , formate, NaOH + H2O2, oxidation to CrOJ , NagP30io, sulfosalicylate, tartrate, triethylam-ine, tiron... 

V (Reduction with) ascorbic acid, hydrazine, or NH2OH HCl, CN , EDTA, F , H2O2, manni-... 

Chromate(VI) Reduction with arsenate(III), ascorbic acid, hydrazine, hydroxylamine, sulfite, or thiosul-... 

Sometimes the metal may be transformed into a different oxidation state thus copper(II) may be reduced in acid solution by hydroxylamine or ascorbic acid. After rendering ammoniacal, nickel or cobalt can be titrated using, for example, murexide as indicator without interference from the copper, which is now present as Cu(I). Iron(III) can often be similarly masked by reduction with ascorbic acid. 

The platinum(II) catalyzed reduction of civ,civ,/rart.v-diaminedihalodihydroxoplatinum(IV) complexes by ascorbate has been reported to proceed via a long-lived platinum(IV)-ascorbate radical.518 Ascorbate reduction of complexes with halides in the axial sites has been reported to proceed via reductive attack on one of these halides.519 This group also showed that reduction by A sc2 occurred seven orders of magnitude more rapidly than reduction by I IAsc and that H2Asc is unreactive.519 Reduction by thiols and methionine is strongly dependent on pH because of a similar variation in reactivity of the protonated and unprotonated forms of the reductants.505,514... 

NH2OH HC1, NH3, NOt, 1,10-phenanthroline, S2-, SCN- + SO -, S20(-, sulfosalicylate, tartrate, thioglycolic acid, thiosemicarbazide, thiocarbohydrazide, thiourea Fe Acetylacetone, (reduction with) ascorbic acid, C2OJ-, citrate, CN-, 2,3-dimercaptopropanol,... 

Hg Acetone, (reduction with) ascorbic acid, citrate, Cl-, CN-, 2,3-dimercaptopropan-l-ol, EDTA,... 

Reduction with) ascorbic acid, hydrazine, or NH2OH HC1, CN-, EDTA, F-, H202, mannitol, oxidation to vanadate, triethanolamine, tiron Citrate, F-, H202, hydrazine, Na5P3O10, NH2OH HC1, oxalate, SCN-, tartrate, tiron, triphosphate, oxidation to tungstate(VI)... 

Olsen et al. [62] have described a method for the determination of pH8.5 sodium bicarbonate extractable phosphorus in soils. The concentration of the blue complex produced by the reduction, with ascorbic acid, of the phosphomolybdate formed when acid ammonium molybdate reacts with phosphate is measured spectrophotometrically at 880 nm [63]. 

Figure 2.8 Redox-driven translocation of a copper center, based on the Cu"/Cu change. The Cu11 ion stays in the tetramine compartment of the ditopic ligand 10, whereas the Cu1 ion prefers to occupy the bis-(2,2 -bipyridine) compartment. The translocation of the copper center between the two compartments is fast and reversible when carried out through the Cun-to-Cu1 reduction with ascorbic acid and Cu -to-Cu" oxidation with H202, in a MeCN solution.

A good route to 2-C-allyl (and hence by reduction, C-alkyl) derivatives of ascorbic acid involves the interaction of L-ascorbic acid with allyl acetates or allyl carbonates in the presence of Pd(0) catalyst.355... 

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