Analytical Sciences

Electrochemical Behavior of 2'-Halogenated Derivatives of N,N-Dimethyl-4-aminoazobenzene at Mercury Electrode

Mustafa UÇAR,*  A. Osman SOLAK,* and Necati MENEK**

*Ankara University, Faculty of Science, Department of Chemistry, Tandogan, 06100 Ankara, Turkey
**Ondokuz Mayis University, Faculty of Science and Arts, Department of Chemistry, 55139 Kurupelit-Samsun, Turkey

The electrochemical behavior of 2'-halogeno-N,N-dimethyl-4-aminoazobenzene derivatives was investigated using various polarographic and voltammetric methods. The peak potentials of these derivatives were observed to shift towards negative values along with an increase in the pH. A reduction of the azo linkage took place via two electrons at pH > 4, but four electrons at pH < 4 in aqueous-ethanol mixtures. The standard rate constants were determined with (Laviron technique) or without (Nicholson technique) taking the adsorption phenomena into account. The diffusion coefficients were calculated from the cyclic voltammetric data using a method developed by Garrido. The amount of adsorbed substances and transfer coefficients for the electron transfer were also determined. A mechanism for the electrode reaction is proposed. These compounds can be quantitatively determined between 1 x 10^-5 M and 1 x 10^-7 with DPP and CV.

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