14701-21-4Relevant articles and documents
Square-wave Amperometric Monitoring of Reaction Rates
Cox, Brian G.,Jedral, Wojciech
, p. 781 - 788 (1984)
The application of square-wave amperometry, an analytical technique involving the use of two indicator electrodes polarized by a square wave, in the determination of reaction rates is described.Kinetic measurements have been made on the bromination of anisole in aqueous solution.Square-wave amperometry in conjunction with a stopped-flow apparatus equipped with Pt electrodes in the observation tube was used to monitor the disappearance of bromine in dilute solutions.Reaction rates with half-lives down to ca. 5 ms can be measured using relatively high-frequency square waves (ca. 800-1000 Hz).The results are in good agreement with values measured spectrophotometrically at higher bromine concentrations.The rate of dissociation of Ag(1+) from its macrobicyclic cryptand 211 complex was also measured, using a pair of silver indicator electrodes.Free Ag(1+) may be monitored selectively in the presence of its cryptate complex by using a low-amplitude square wave (+/- 150 mV).The advantages and limitations of the amperometric technique for kinetic measurements are discussed.
Features of electrolysis of nitric acid solutions of silver: I. Behavior of Ag(II) in HNO3 solutions
Rance,Nikitina,Korolev,Kirshin,Listopadov,Egorova
, p. 346 - 352 (2003)
The current efficiency of Ag(II) formation in the course of electrochemical oxidative dissolution of PuO2 was determined. It approaches 72% at the anodic potentials from 1.9 to 2.1 V (vs. SHE) and the anodic current densities of 0.006-0.013 A cm-2. The behavior of Ag(II) in 4 M HNO3 at 8, 25, and 40°C was studied. The reaction of Ag(II) with water can be described by the equation d[Ag(II)]/dt = kapp[Ag(II)] n, where n ～ 2 at 8-25°C and 2-1.5 at 39-41°C. The apparent rate constants of the reaction are 1.5 and 3.8 1 mol-1 min-1 at 8.5°C and 25°C, respectively. At 39-41°C, the reaction order with respect to Ag(II) ranges from 2 to 1.5, and the rate constant is about 1.2 11/2 mol-1/2 min-1.
Dual mechanism of oxidation of dl-methionine by diperiodatoargentate(III) in aqueous alkaline medium (stopped flow technique)
Thabaj,Chimatadar,Nandibewoor
, p. 88 - 95 (2008)
The kinetics of oxidation of dl-methionine by diperiodatoargentate(III) (DPA) has been studied spectrophotometrically in a wide range, 0.01-1.0 mol dm-3, of alkali at constant ionic strength of 0.50 mol dm-3. In a lower range, 0.01-0
Complex Formation followed by Internal Electron Transfer: the Reaction of silver(III) with Ascorbic Acid
Dasgupta, Subrata,Herlinger, Erwin,Linert, Wolfgang
, p. 567 - 570 (1993)
silver(III) 3+ 1 has been found to oxidize ascorbic acid (H2asc) in acidic aqueous solution via an inner-sphere mechanism to give dehydroascorbic acid, silver(I) and free ethylenebis(biguanide).The 1:1 adduct formed as an intermediate between 1 and ascorbic acid decomposes after a non-separable two-electron-transfer reaction.The decomposition of the three complexes actually formed, co-ordinating different numbers of protons, occurs through two parallel pathways: one via decomposition of the unprotonated adduct III(H2L)(H2asc)>, another via the deprotonated adduct III(H2L)(Hasc)>, while the protonated adduct III(H3L)(H2asc)> appears to be rather stable.The equilibrium constant for the adduct formation has been found to be 4.08 +/- 0.45 dm3 mol-1, whereas the acid and base constants of this complex are 0.41 mol dm-3 and 2.86 dm3 mol-1, respectively.The two rate constants for the decomposition are 25 +/- 3 and 220 +/- 25 s-1 for III(H2L)(H2asc)> and III(H2L)(Hasc)>, respectively.The possibility of an outer-sphere mechanism is discussed.
Kinetics of the reaction of silver(II) with dithionate
Veith, Gilman,Guthals, Elise,Viste, Arlen
, p. 667 - 669 (1967)
The reaction 2Ag(II) + S2O62- + 2H2O = 2Ag+ + 2HSO4- + 2H+ proceeds by a mechanism in which the oxidizing agent, silver(II), participates in the rate-determining step. This is unlike previously known reactions of dithionate with certain strong oxidizing agents, for which disproportionation or hydrolysis of dithionate has been rate determining. The dominant term in the rate law is -d[Ag(II)]/dt = k[H+][Ag(II)][S2O62-], with k = 5.5 × 10-2 M-2 sec-1 at I = 3.5 M and 25.0°.
Kinetics of dissolution of silver nanoparticles inside triton N-42 reversed micelles
Tatarchuk,Bulavchenko,Druzhinina
, p. 1678 - 1683 (2009)
Our spectrophotometric study of the kinetics of dissolution of silver nanoparticles by nitric acid inside inverted micelles of Triton N-42 (a nonionic surfactant) verified the universal character of the mechanism for this type of process, which includes t
Kinetics of Oxidation of Azide by [Ethylenebis(biguanide)]silver(III) in Aqueous Acidic Media
Bandyopadhyay, Prabir,Dhar, Basab Bijayi,Bhattacharyya, Jhimli,Mukhopadhyay, Subrata
, p. 4308 - 4312 (2003)
In aqueous acidic media sodium azide and the orange-yellow title complex react quantitatively generating N2 gas along with a colourless solution of Ag+ ion and the ligand, ethylenebis(biguanide). The parent complex, [Ag(H2L)]3+, and one of its conjugate bases, [Ag(HL)]2+, participate in the reaction with N 3- as the kinetically reactive reductant. Ag+ has no catalytic effect. At 25.0 °C, I = 1.0 M (NaNO3), rate constants for the reactions [Ag(H2L)]3+ + N 3- and that for [Ag(HL)]2+ + N3 - are (12.3±0.5) and (3.8±0.6) M-1· S-1, respectively. The high rate constants along with the very low equilibrium constant (10-15 M-1) calculated for the first reaction strongly suggest inner-sphere redox mechanism. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
Gas-phase studies of group-11 cation (Cu+, Ag+, and Au+) reactions with 2-propanol in a supersonic beam-expansion source
Huang,Su,Yeh
, p. 677 - 688 (2001)
The gas-phase reactions of group-11 ions (Cu+,Ag+, and Au+) with 2-propanol were investigated using laser vaporization combined with supersonic beam expansion in a time-of-flight mass spectrometer. A number of reaction pathways, including assoication, dehydrogenation, and dehydration, were observed. Among these metal ions, Au+ is highly reactive toward 2-propanol. The experimental results are parallel to studies by Wilkins et al. using an FT-ICR mass spectrometer (J. Am. Chem. Soc., 107, 7316 (1985)). The geometries and binding energies of all complexes M+-L, where M+ = Cu+, Ag+, and Au+, L = 2-propanol, acetone, propene, and H2O, were estimated using Moller-Plesset perturbation (MP2) and density functional theory (BLYP). The bond strengths of the complex ions involving gold revealed the strongest bonding, due to a relativistic effect. The energetic relationship between the reactants and the products facilitated an interpretation of the observed exit channels. Because of the supersonic beam source employed, larger clusters containing metal ions were generated as well. Because the cluster sizes with solvent molecules were ≥ 2, the reactivities were apparently limited to Cu+ and Ag+ clusters, while the reactive nature changed in Au+ along with the formation of acetone, lacking in the bare Au+ reactions. For larger clusters, calculations on Ag+ - (2-propanol)2 and Ag+ - (2-propanol)(acetone) complexes using BLYP were performed to obtain their energetics.
Kinetics of oxidation of glyoxylic acid by [ethylenebis(biguanide)] silver(III) in aqueous media
Das, Amit,Mukhopadhyay, Subrata
, p. 895 - 901 (2004)
The complex cation, [ethylenebis(biguanide)]silver(III), [Ag(H 2L)]3+, and its conjugate bases, [Ag(HL)]2+ and [AgL]+ oxidise glyoxylic acid, CHOCO2H quantitatively to formic acid and carbon dioxide, themselves being reduced to Ag+. Free ethylenebis(biguanide) was recovered in near-quantitative yield. In the investigated pH range (1.00-7.00), the reaction is first order in both [complex] and total glyoxylate, [HGX]T. The reaction proceeds through four parallel paths: [Ag(H2L)]3+ - HGX (k1), [Ag(H2L)]3+ - GX- (k2), [Ag(HL)]2+ - GX- (k3), and [AgL]+ - GX- (k4). The respective rate constants (in 10 4 M-1s-1) are, respectively, 7.34, 112, 40.7 and 19.2 at 25.0°C and I = 1.0 M (NaNO3). Formation of adducts by the reducing species with the metal complex via hydrogen-bonding or electrostriction may be proposed for the low-energy pathway for electron-transfer. A substantial rate retardation in presence of the radical scavenger acrylonitrile suggests successive one-electron changes, Ag III → AgII → AgI.
Luminescent coordination polymers with extended Au(I)-Ag(I) interactions supported by a pyridyl-substituted NHC ligand
Catalano, Vincent J.,Etogo, Anthony O.
, p. 6041 - 6050 (2005)
Reaction of [Ag(CH3impy)2]PF6, 1, with Au(tht)Cl produces the monometallic Au(I)-species [Au(CH3impy) 2]PF6, 2. Treatment of 2 with excess AgBF4 in acetonitrile, benzonitrile or benzylnitrile produces the polymeric species {[AuAg(CH3impy)2(L)](BF4)2} n, (L = CH3CN,3; L = C6H5CN, 4; L = C6H5CH2CN, 5) where the Au(I) centers remain bound to two carbene moieties while the Ag(I) centers are coordinated to two alternating pyridyl groups and a solvent molecule (L). Reaction of 2 with AgNO3 in acetonitrile produces the zig-zag mixed-metal polymer {[AuAg(CH3impy)2(NO3)]NO3} n, 6, that contains a coordinated nitrate ion in place of the coordinated solvent species. All of these polymeric materials are dynamic in solution and dissociate into their respective monometallic components. Compounds 2-6 are intensely luminescent in the solid-state and in frozen solution. All of these complexes were characterized by 1H, 13C NMR, electronic absorption and emission spectroscopy and elemental analysis.
