Kinetics and Mechanism of Redox Reaction between Tetrachloroaurate(III) Ions and Hydrazine

In this work, the kinetics and mechanism of a redox reaction between the [AuCl4](-) complex ions and hydrazine in aqueous solution were carried out. Using a combination of the classical UV-vis spectrophotometry and the stopped-flow technique, the impact of different parameters, such as pH, ionic strength, temperature, the presence of chloride ions, and [AuCl4](-) and N2H5+ concentrations on the rate constant of [AuCl4](-) reduction was investigated. From the obtained results, the rate law of the reaction was determined and the possible mechanism of a one-electron inner-sphere reaction was suggested. It has been found that the reaction is complex and consists of at least two consecutive steps with the gold(I) formation, which can be further reduced to a metallic form as a final product of the reaction. (C) 2014 Wiley Periodicals, Inc.