Study of electrochemical behavior of two chemically similar acridines: Tacrine and 9-aminoacridine on hanging mercury drop electrode

Abstract

ABSTRACT. The electrochemical behavior of two chemically related acridine compounds: tacrine (TAC) and 9-aminoacridine (9-AA) was investigated on a hanging mercury drop electrode (HDME). The electrochemical study was carried out by using Osteryoung square wave voltammetry (OSWV) and cyclic voltammetry (CV) techniques in the Britton-Robinson (B-R) buffer solution at pH = 2.0–12.0, KCl (0.1/0.2/0.3 M) and methanol (0.0-50%) mixture as supporting electrolyte. TAC showed maximum current at pH 7.5 while 9-AA at pH 10, KCl (0.3M), and 10% methanol. The study of electrochemical reduction of 9-AA and TAC on the HDME by using CV resulted in a quasi-reversibility, mainly diffusion-controlled reaction. The reaction involved 1e–/1H+ reduction at nitrogen atom in the case of the 9-AA while the second process involved the 2e–/2H+ reduction of the intra-cyclic azomethine group. The reduction peak potential of structurally related acridine compounds is influenced by the pH values and percentage of the organic solvent of the supporting electrolytes. Also, the study may provide insight into the electron transfer pathways of biological reactions of the acridines and their electrochemical behavior on the electrode.                     KEY WORDS: Tacrine, 9-Aminoacridine, Cyclic voltammetry, Osteryoung square wave voltammetry, Hanging mercury dropping electrode   Bull. Chem. Soc. Ethiop. 2021, 35(3), 639-646. DOI: https://dx.doi.org/10.4314/bcse.v35i3.14