Structural and Solvent Dependence of the Electronic Properties and Corrosion Inhibitive Potentials of 1,3,4-thiadiazole and Its Substituted Derivatives- A Theoretical Investigation

The frontier molecular orbitals (FMOs) are very important for describing chemical reactivity and understanding the static molecular reactivity. The HOMO and LUMO energies of 1,3,4-thiadiazole and its substituted derivatives were calculated using the hybrid B3LYP method with a large polar 6-31G* basis set in vacuum, acetone, ethanol and tetrahydrofuran (THF). It was revealed that substitution at position -2 with -NO2, -CH3, -NH2, -CN and -CH=C(CN)COOH results in enhanced reactivities due to reduction of the energy band gap, Eg. It also altered some important molecular properties like η, S, ΔN, μ, α and β. Substituted -NO2, -CN and -CH=C(CN)COOH may possess better inhibitive potentials and better reactivities than other derivatives on the basis of studied parameters. It was observed that solvent media affect molecular properties.