Abstract
Electrochemical behavior of three biologically important triazole and phenol containing Schiff bases (E)-3-((4H-1,2,4 triazol-4-ylimino)methyl)benzene-1,2-diol (TMB), (E)-3-((4H-1,2,4 triazol-4-ylimino) methyl) para-phenol (p-TMP) and (E)-3-((4H-1,2,4 triazol-4-ylimino) methyl) ortho-phenol (o-TMP) were investigated by electrochemical, spectroscopic and computational methods. The peak potential of all the three compounds showed a linear dependence on pH under acidic conditions, but under alkaline conditions, electron transfer was not coupled to proton transfer. The acid-base dissociation constant (pKa) values of the compounds were evaluated both by electrochemical and UV-Vis spectroscopic techniques. On the basis of experimental and theoretical findings, redox mechanisms of the compounds were proposed and certain important kinetic and thermodynamic parameters were determined from their temperature and pH responsive redox response. Our studies showed a) low cytotoxicity for all three triazoles and b) antioxidant properties of these triazoles. TMB was found as the most promising antioxidant, which makes this compound interesting as a basis for further development as food supplement. (C) 2016 The Electrochemical Society. All rights reserved.