Collect. Czech. Chem. Commun. 2004, 69, 267-278

The Influence of Diaminotoluene Isomers on the Two-Step Electroreduction of Zn(II) Ions in Acetate Buffers at Different Acidities

Grażyna Dalmata, Agnieszka Nosal-Wiercińska* and Teresa Zięcina

Faculty of Chemistry, Maria Curie-Skłodowska University, 20-031 Lublin, Poland


The influence of diaminotoluene isomers on the two-step reduction of Zn(II) ions on the mercury electrode in acetate buffers at different acidities was examined. It was stated that 2,4- and 2,6-diaminotoluene inhibit the electroreduction process of Zn(II) ions, while 3,4-diaminotoluene, in dependence on pH of acetate buffer, can act as inhibitor or catalyst. The differences in activity of these isomers result mainly from their complex formation properties. The catalytic activity of 3,4-diaminotoluene is associated with removing of the coordinated water molecules from the hydration sphere of Zn(II) ions and with the formation of active complexes on the electrode surface. This reaction controls the total rate of the process. The active complexes participate in consecutive electron transfer. Both steps of electron transfer are catalysed by 3,4-diaminotoluene.

Keywords: Electrochemistry; Electrochemical reduction; Zinc; Acidity; Inhibition; Catalysis; Rate constants; 3,4-Diaminotoluene.

References: 35 live references.