20681-14-5Relevant articles and documents
Sengupta, Kalyan Kali,Basu, Biswanath,Sengupta, Shipra,Nandi, Sanghamitra
, p. 983 - 986 (1983)
Kinetic spectrophotometric method for o-phenylenediamine in the presence of gold(III)
Altun, Oezlen,Akbas, Halide,Doelen, Emre
, p. 499 - 502 (2007)
From the color developing reactions of o-phenylenediamine oxidizing agent and gold(III), the kinetic reactions between both of them in aquaeous solutions were studied using spectrophotometric and differential method. Light absorbances in the visible spectral range are measured as a function of mole fractions of phenylenediamine at a fixed gold(III) concentration and as a function of mole fraction of gold(III) at a fixed o-phenylenediamine concentration at periodic time internal. In the differential method, which was suggested by van't Hoff, one deals with the actual rates of reactions as determined by measuring the slopes of absorbance-time curves. Optimum condition of the reaction were established as pH 6 at λ = 466 nm and room temperature. When the oxidation of o-phenylenediamine by gold(III) was investigated, it was observed that the following rate formula and rate constant were found: v = k [ A u+ 3 ]1 / 2 [ o -phenylenediamine ]1 / 2, k = 2.33 × 10- 2 s- 1.
Cyanide and chloride exchange on homoleptic gold(III) square-planar complexes: Variable pressure kinetic investigation by heteronuclear NMR
Monlien, Florence J.,Helm, Lothar,Abou-Hamdan, Amira,Merbach, André E.
, p. 257 - 269 (2008/10/08)
Kinetic studies of X- exchange on [AuX4]- square-planar complexes (where X=Cl- and CN-) were performed at acidic pH in the case of chloride system and as a function of pH for the cyanide one. Chloride NMR study (330-365 K) gives a second-order rate law on [AuCl4]- with the kinetic parameters: (k2Au,Cl)298=0.56±0.03 s-1mol-1kg; ΔH2?Au,Cl=65.1±1 kJmol-1; ΔS2?Au,Cl=-31.3±3 Jmol-1K-1 and ΔV2?Au,Cl=-14±2 cm3mol-1. The variable pressure data clearly indicate the operation of an Ia or A mechanism for this exchange pathway. The proton exchange on HCN was determined by 13C NMR as a function of pH and the rate constant of the three reaction pathways involving H2O, OH- and CN- were determined: k0HCN,H=113±17 s-1, k1HCN,H=(2.9±0.7)×109 s-1mol-1kg and k2HCN,H=(0.6±0.2)×106 s-1mol-1kg at 298.1 K. The rate law of the cyanide exchange on [Au(CN)4]- was found to be second order with the following kinetic parameters: (k2Au,CN)298=6240±85 s-1mol-1kg, ΔH2?Au,CN=40.0±0.8 kJmol-1, ΔS2?Au,CN=-37.8±3 Jmol-1K-1 and ΔV2?Au,CN=+2±1 cm3mol-1. The rate constant observed varies about nine orders of magnitude depending on the pH and HCN does not act as a nucleophile. The observed rate constant of X- exchange on [AuX4]- are two or three orders of magnitude faster than the Pt(II) analogue.
Reaction of carbon monoxide in the superacid HSO3F-Au(SO3F)3 and the gold(I) bis(carbonyl) cation [Au(CO)2]+. Isolation and characterization of gold(I) carbonyl fluorosulfate, Au(CO)SO3F
Willner, Helge,Aubke
, p. 2195 - 2200 (2008/10/08)
Solutions of gold tris(fluorosulfate), Au(SO3F)3, in fluorosulfuric acid, HSO3F, behave as superacids and will dissolve up to ～3.5 mol of CO/mol of Au(SO3F)3. During the CO uptake, Au(III) is reduced to Au(I), with Au+(solv) stabilized by CO to give the cation [(OC)Au(CO)]+(solv). The linear five-atom cation is characterized by its vibrational spectrum with CO stretching frequencies observed at 2251 (Raman) and 2211 (IR) cm-1. The cation is stable in solution, but solvent removal in vacuo leads to the formation of a new gold(I) monocarbonyl derivative, Au(CO)SO3F, in quantitative yield as a white solid. Au(CO)SO3F is thermally stable up to 190°C. The CO stretch is found at 2198 and 2195 cm-1 in the Raman and IR spectra, respectively, well above the value of free CO.
