RETRACTED: Density-functional theory studies on electrode potentials and electronic structure of ( E)-3-(4,5-dihydroxy-2-tosylphenyl) acrylic acid as a new caffeic acid derivative: Experimental and theoretical

Abstract

DFT (B3LYP/6-31G(d) and B3PW91/6-31G(d)) calculations were performed for (E)-3-(4,5-dihydroxy-2-tosylphenyl) acrylic acid (DTA). The calculated IR spectrum of DTA and (2E)-3-(3,4-dioxo-6-tosylcyclohexa-l,5-dienyl) acrylic acid (DTDA) were used for the assignment of IR frequencies. Correlation between theoretical and experimental vibrational frequencies of DTA molecule was 0.994. DTA has two geometric structures, cis and trans. Since the cis structure of caffeic is unstable, it can not be found in nature, but in this research, its electrode potential have been calculated theoretically. Electrode potential of DTA solution obtained by cyclic voltammetry on the surface of a glassy-carbon electrode is 0.328 V. The electrode potentials were also calculated using the energies of solvation and the sum of electronic and thermal free energies of the species. The observed and calculated changes in the reduction potential of DTA differ from those of the reference compound caffeic acid by just 0.010 and 0.016 V for B3LYP and B3PW91, respectively, providing a method by which the reduction potentials of related molecules can be predicted very accurately.