Manganese pyrophosphate complex

The structure of the active component, manganese pyrophosphate, has been reported in the literature (24). It is layer like with planes of octahedrally coordinated Hn ions being separated by planes of pyrophosphate anions (P20y ). Examination of models of this compound gave calculated Hn-Hn thru space distances of 3.26 and 3.45 angstroms, a metal-metal distance close to that found for binuclear dibridged peroxo- and superoxo- complexes of cobalt ( ). 

In dilute H2SO4 or HCIO4 containing oxidants (BrOs , Cr207 ) manganese(II) reacts with phosphoric acid to give the violet Mn(III) pyrophosphate complex (e = 7.5-10 ) [49-52]. The anionic Mn(III) pyrophosphate complex can be extracted into chloroform in the... 

Manganese " " sulfate/sodium pyrophosphate complex Water... 

The effect of acetonitrile on the kinetics of oxidation of ascorbic acid by Cu(II) and the ferrocenium ion in aqueous acetonitrile has been studied, as has the similar oxidation using the Cu(II)-tyrosine complex, for which a mechanism has been proposed. A reinvestigation of the oxidation of ascorbic acid by Fe(III) has shown catalysis by even small amounts of added chloride, 7 and the kinetics and mechanism of the oxidation of ascorbate by manganese pyrophosphate have been studied. The heat stability of aqueous solutions of ascorbic acid is increased witli reduced o gen concentrations, with Cu(II) and Fe(II) accelerating decomposition. ... 

The main reactions of the dioxides are related to their oxidising power. They oxidise hydrazine to nitrogen and they are reduced to MnOOH. The reduced products are leached with pyrophosphate giving the coloured Mn(III) pyrophosphate complex. The solubility of the solids in acidified ascorbic acid is due to reduction to Mn(II). Manganese dioxides oxidise Cr(lll) to dichromate. Even their catalytic role in the decomposition of hydrogen peroxide involves a redox catalytic cycle. 

The Mn(II)-catalysed oxidation of glucose by peroxodisulfate ions occurs via a radical-chain mechanism.26 Kinetics of oxidation of thiodiglycollic acid by (trans-cyclohexane-l,2-diaminc-/V, N, N, /V -tetraacetatolmanganateilJI) have been investigated.27 Oxidations of ketoses and aldoses by manganese(IV) in sulfuric acid media have a first-order dependence on sugar and fractional-order dependence on oxidant.28 A mechanism has been proposed for the oxidation of L-malic acid by Mn(III) pyrophosphate in aqueous acid, involving complex formation and radicals.29... 

Fig. 1. Manganese to phosphorus distances in inner sphere, distorted inner sphere, adjacent pyrophosphate and second sphere complexes from crystallographic and model building studies. Original references are given in (14—16). Corresponding distances in Ca2+ complexes would be 0.2 A greater and in Mg2+ complexes 0.1 A smaller...

Manganese(iii) was detected spectrophotometrically as a short-lived intermediate in the oxidation of cw-but-2-ene-l,4-diol (CBD). Addition of pyrophosphate traps Mn ii by forming the stable pyrophosphatomanganate(ra) complex. In the presence of this reagent, the rate of oxidation may be described by... 

Bilinski, H. Morgan, J.J. "Complex formation and oxygenation of manganese(II) in pyrophosphate solutions". Abstract presented before the Division of Water, Air, and Waste Chemistry 1969, American Chemical Society National Meeting, Minneapolis, Mn. 

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