Electroanalytical chemistry of metal complexes with S-containing ligands

Abstract

The main types of electrochemical reactions of complexes in organic and mixed solvents are considered. Fast electrochemical reactions (ks=n×10−2 cm · s−1) were used to reduce the minimal concentrations (cmin) in a.c. voltammetry. The role of pre- and post-chemical reactions in the formation of the analytical signal in extraction voltammetry is elucidated. The principles of the influence of the special structure of the complexes on their redox properties are determined using complexes of the transition metals with phosphorus dithioacids and bidentate heterocyclic amines. The features of the electrooxidation and electroreduction of inert complexes of the platinum metals with heterocyclic dithioacids and organic sulphides in nonaqueous media are discussed. The products of the electrochemical reaction of these compounds in protic media catalyze the hydrogen evolution on the mercury electrode. Kinetic data of the chelate formation are used for developing highly selective methods for the determination of the platinum metals with cmin=2×10−9−5×10−8 mol/l.