Kinetics and Mechanism for Reduction of Tetrachloroaurate(III), trans-dicyanodichloroaurate(III), and trans-dicyanodibromoaurate(III) by Sulfite and Hydrogen Sulfite
Reduction of [AuCl4]- and trans-[Au(CN)2X2]- (X = Cl, Br) by sulfur(IV) as SO2.nH2O, HSO3-, and SO3(2-) has been studied at 25-degrees-C in aqueous solution with ionic strength 1.0 M and 0 < pH < 2.3 by use of stopped-flow spectrophotometry. Redox takes place directly without initial substitution at the gold(III) centers with stoichiometry Au(III):S(IV) = 1:1 and with Au(I) complexes and HSO4- as