Investigation of Resonance Effect, Inductive Effect, Solvation Energies and Electron Affinities of Some Thiosemicarbazides, Hydrazides and Carboxylic Acids through Linear Scan Voltammetry

Electrochemical measurements have been carried out for three sets of compounds. Set I comprising fourteen 4-(4-substitutedphenyl)-l-(isomericpyridoyl)thiosemicarbazides, Set 2 comprising three isomeric pyridine carboxylic acid hydrazides and Set 3 comprising three isomeric pyridine carboxylic acids. In all these compounds substituents on phenyl group arc bromo, chloro, fiuoro, methyl and methoxy group. All these compounds were studied in non·aqueous solvent DMF at 293K using linear scan voltammetry (LSV) as measuring techniques. LSV reveals a single reversible peak for all compounds. Effects of substituents on halfwave potential (E½) values were explained on thebasis of resonance and inductive effects. E½ values were used for the evaluation of solvationenergies (S) and electron affinities (A). Moreover, correlations of energies of lowest unoccupiedmolecular orbitals (ELUMO) and Hammett constants (a with halfwave potentials (E½) and electronaffinities (A) were also studied.