Synthesis, Spectroscopic Characterization, pH Dependent Electrochemistry and Computational Studies of Piperazinic Compounds

Abstract

This work presents the synthesis, redox behavior and spectroscopic characterization of two novel compounds Sodium 4-(3-methoxyphenyl) piperazine-1-carbodithioate and sodium 4-(4-nitrophenyl) piperazine-1-carbodithioate. Pulse voltammetric techniques were utilized to determine the number of electrons involved in the oxidation and/or the reduction step and to ensure the nature of the redox processes. The pH dependent redox mechanistic pathways of the compounds were proposed on the basis of electrochemical and computational results. Different thermodynamic parameters like ΔG# and ΔH# revealed that electrode processes are non-spontaneous and endergonic in nature. Increase in ΔS# values at higher temperature indicated the randomness of the electrode reactions at higher temperatures. Limits of detection and quantification were determined by square wave voltammetry due to its high sensitivity and fast speed. Ionization energy, electron affinity, dipole moment and charge distribution on atoms were computationally determined. Acid-base dissociation constant (pKa) values of the compounds evaluated by voltammetry and electronic spectroscopy were found comparable.