16397-91-4Relevant academic research and scientific papers
Oxidation of NIII and N-I by an {Mn4O 6}4+ core in aqueous media: Proton-coupled electron transfer
Das, Suranjana,Mukhopadhyay, Subrata
, p. 4500 - 4507 (2007)
[Mn4(μ-O)6(bipy)6]4+ (1 4+; bipy = 2,2′-bipyridine) and its conjugate acid [Mn 4(μ-O)5(μ-OH)(bipy)6]5+ (1H5+) quantitatively oxidise NIII (HNO2 and NO2-) and N-1 (NH3OH+ and NH2OH) to NV (nitrate) and NI (nitrous oxide), respectively, in aqueous solution (pH 2.0-6.0), with 1H5+ reacting much faster than 14+. An uncommon feature of these reactions is the kinetic superiority of HNO2 over its conjugate base NO 2-. NH2OH, however, behaves normally - the conjugate acid NH3OH+ is less reactive than NH 2OH. These reactions show remarkable kinetic isotope effects: the observed rate of NIII oxidation increases in D2O media whereas the N-I oxidation rate slows down in media enriched with D2O. A search of the available data on the redox kinetics of multinuclear oxidants suggests that the title {Mn4O6} 4+ reduction by NIII, the rate of which is accelerated in D2O, is the only one established so far. A hydrogen atom transfer (HAT) mechanism (1e, 1H+; electroprotic) is proposed. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
Solution Equilibria and Redox Reactivities of a Dioxo-bridged Manganese Complex
Chaudhuri, Swapan,Mukhopadhyay, Subrata,Banerjee, Rupendranath
, p. 621 - 624 (1995)
The dinuclear complex (3+) (bipy = 2,2'-bipyridyl) 1 was stabilised in bipy-Hbipy(+) buffer where it coexists with the diaqua derivative (3+) 2 (equilibrium constant KH).Reduction of 1 by NO2(-) has been found to be kinetically insignificant, but that of 2 is rapid, quantitative and follows the sequence Mn(III)Mn(IV) (Mn(III))2 Mn(II)Mn(III) 2Mn(II).In the presence of an excess of NO2(-), first-order kinetics was observed at 830 nm, but a biphasic profile at 525 nm.At 30.0 deg C and I = 1.0 mol dm-3, k1KH1 and K2KH2 are 34.9 +/- 0.8 and 3.3 +/- 0.2 dm3 mol-1 s-1 respectively.Added bipy retards, while Mn(2+) accelerates, the reaction.The solution equilibria are much more complex for 1 in HNO3 and H3PO4, but the known solution chemistry of 1 in such different media may be correlated by a unified reaction scheme.
Redox chemistry of metal-catechol complexes in aprotic media. 2. 3,5-Di-tert-butylcatecholato complexes of manganese(IV) and manganese(III)
Jones, Stephen E.,Chin, Der-Hang,Sawyer, Donald T.
, p. 4257 - 4262 (1981)
When mixtures of manganese(II) and 3,5-di-tert-butyl-o-quinone (DTBQ) with mole ratios of 1:3 and 1:2 are reduced in aprotic solvents, stable MnIV(DTBC)32- and MnIII(DTBC)2- complexes are formed, respectively (DTBC represents the dianion of di-tert-butylcatechol). These complexes and their oxidation-reduction products have been characterized by cyclic voltammetry, controlled-potential electrolysis, optical spectroscopy, ESR spectroscopy, and magnetic susceptibility measurements in dimethylformamide, dimethyl sulfoxide, and acetonitrile solvents. On the basis of these results, a self-consistent redox mechanism is presented for the interconversion of the various species of manganese(II)-DTBQ systems with mole ratios of 1:1, 1:2, and 1:3. The catechol complexes of manganese(II), -(III), and -(IV) are versatile electron-transfer agents and should be effective redox catalysts and oxygen activators.
Manganese(II)-superoxide complex in aqueous solution
Jacobsen, Frank,Holcman, Jerzy,Sehested, Knud
, p. 1324 - 1328 (1997)
Mn(II)aq-superoxide complex, MnO2+, was formed in pulse radiolysis by three distinct routes: Mn(I) + O2, Mn(II) + O2- and Mn(III) + H2O2. The stability of this complex
Kinetics of the Permanganate-Iron(II) Reaction in Aqueous Acid Medium
Sutter, John R.,Park, Kee B.
, p. 770 - 772 (1984)
The kinetics of the permanganate-iron(II) redox reaction has been studied in aqueous perchloric acid at 20 deg C by using stopped-flow techniques.The disappearance of permanganate was followed at 525 nm, with use of excess iron, and consisted of two consecutive first-order decays.A mechanism consistent with the data is MnO4- + Fe2+ O3MnOFe+ (k1, k-1), O3MnFe+ -> Mn(VI) + Fe(III) (k2).The rate constants are k1 = 9.97E4 M-1 s-1, k-1 = 16.4 s-1, and k2 = 12.9 s-1.No dependence on H+ or salt was observed in either step.
The kinetics and mechanism of the decomposition reaction of the bis(oxalato)manganese(III) complex in an aqueous solution
Kimura,Ohota,Tsukahara
, p. 151 - 155 (1990)
The kinetics and mechanism of the decomposition of the bis(oxalato)manganase(III) complex ion ([Mn(ox)2]-) were studied in acid solution in the absence and in the presence of oxygen at temperatures from 10 to 35°C. The decomposition reaction of [Mn(ox)2]- in the absence of oxygen was described by the first-order rate law of -d[[Mn(ox)2]-]/dt=k(obsd)[[Mn(ox)2]-], where the observed rate constant, k(obsd), increased proportionally with the increasing hydrogen-ion concentrations, being expressed as k(obsd)=k[H+] in the [H+] range of 0.006-0.1 M. The enthalpy and entropy changes of activation (ΔH≠ and ΔS≠) were 73.4±2.0 kJ mol-1 and -8.6±0.2 J K-1 mol-1 respectively. The rate of the decomposition of [Mn(ox)2]- decreased greatly upon the addition of a radical scavenger for CO2-. such as [Co(NH3)6]3+, [CoCl(NH3)5]2+, or molecular oxygen. In the presence of oxygen, the rate deviated greatly from the first-order rate law. On the other hand, the addition of [Co(NH3)6]3+ or [CoCl(NH3)5]2+ in the absence of oxygen did not change the first-order rate law, but did decrease the rate of reaction up to 40% of that in the absence of the radical scavenger. The mechanisms for the decomposition reaction of [Mn(ox)2]- are discussed in the light of the results obtained.
Kinetics of Manganese Dioxide Dissolution in Sulfuric Acid Solutions Containing Oxalic Acid
Batrakov,Gorichev,Prigozhaya,Izotov,Kuznetsov
, p. 149 - 156 (2008/10/08)
The kinetics of manganese dioxide dissolution were studied in sulfuric acid solutions containing oxalic acid. The dissolution rate was found to depend on the concentrations of MnHOx+ and HOx- ions and to pass through a maximum at pH 1.6±0.2. The rate law and mechanism are suggested for manganese dioxide dissolution.
Heteropolyvanadomanganates(IV) with Mn:V = 1:11 and 1:4
Flynn Jr.,Pope, Michael T.
, p. 2009 - 2014 (2008/10/08)
Two new vanadomanganate(IV) heteropoly complexes have been prepared by reaction of manganese(II), peroxydisulfate, and isopolyvanadate(V) ions. One complex, isolated as K5MnV11O32·10H2O, Cs4.5H0.5MnV11O32·7H 2O, and (NH4)4.5H0.5MnV11O 32·12H2O (all red to dark red crystals) is moderately stable in solutions of pH 2-3. In the pH range 4-6 it reacts to give high yields of 13-vanadomanganate(IV), accompanied by some amorphous precipitate and at least one other complex in low yields. The second complex, isolated as K5HMn3V12O39·10H2O and (NH4)5HMn3V12O 89·15H2O (black crystals), is also obtained in the pH range 2-3 and apparently exists up to a pH near 6. It is formulated as a trimeric species on the basis of the chemical analyses and single-crystal X-ray data. The 3:12 complex is unexpectedly inert to reaction with excess vanadium(V) to give 1:11 or 1:13 complexes. No visual evidence for heteropoly blue species was observed on reduction of the complexes. The 1:13 complex was found to be slightly photosensitive, the decomposition products apparently including the green reduced species. The acid decomposition of vanadomanganates(IV) leads to formation of small quantities of permanganate; similar behavior was noted for 12-niobomanganate(IV).
