Quantum Chemical Assessment of Two Natural Compounds: Vasicine and Vasicinone as Green Corrosion Inhibitors.

Abstract

A theoretical study has been performed on the main Vasicine and Vasicinone molecules found in Adhatoda vasica plant extract using the Density Functional Theory (DFT). Through this study, the inhibitive effect of these two molecules to reduce the corrosion rate of mild steel in acidic medium is elucidated. The parameters such as dipole moment (μ), E HOMO , E LUMO , energy gap (ΔE), global hardness (η), chemical softness (S), electron affinity (A), ionization potential (I), the absolute electronegativity (χ), the fraction of electron transfer from the inhibitor molecule to the metallic atom (ΔN) and Mulliken charges have been calculated. All calculations have been carried out taking into account the Density Functional Theory (DFT) using the GAUSSIAN 03W computational program. The results showed that Vasicinone molecule is favorably adsorbed on the metal surface (Fe) through the electronegative density atoms as active centers of adsorption, and the theoretical conclusions were found to be in agreement with the experimental reported data.

Corrosion Behavior of Titanium in Simulated Body Solutions with the Addition of Biomolecules

“…After that, electrons flow from the molecule with a lower electronegativity to the molecule with a higher electronegativity until their electronegativities become equal. − Therefore, a high value of electronegativity indicates that the compound is less capable of donating its electrons to the acceptor molecule. , Ionization energy is one of the most important indicators of the reactivity of compounds. High values of ionization energy point to chemical inertness of the molecule, while small values of ionization energy confirm high reactivity of the compound . The obtained results of the ionization energy of AD, THY, and HIS indicate that adenine is more reactive and has higher inhibition efficiency than thymine and l -histidine, which is in agreement with electrochemical tests.…”

“…High values of ionization energy point to chemical inertness of the molecule, while small values of ionization energy confirm high reactivity of the compound. 86 The obtained results of the ionization energy of AD, THY, and HIS indicate that adenine is more reactive and has higher inhibition efficiency than thymine and L-histidine, which is in agreement with electrochemical tests.…”

Transition metal complexes of 6‐mercaptopurine: Characterization, Theoretical calculation, DNA‐Binding, molecular docking, and anticancer activity

“…[ 29 ] The lowest values were for copper and cobalt compounds, which might have better inhibition efficiencies. [ 33 ] Global hardness ( η ) is the reverse of global softness ( σ ), and they indicate reactivity and the extent of stability; metal complexes represent higher reactivity than the organic molecule in binding to biological targets. [ 29 ] The electrophilicity index ( ω ) is an indication of the ability to react to negative pieces and accept electrons; it follows this trend: 6‐MP > Fe(II) > Zn(II) > Cu(II) > Ni(II) > Co(II).…”

“…[29] The lowest values were for copper and cobalt compounds, which might have better inhibition efficiencies. [33] 3. Global hardness (η) is the reverse of global softness (σ), and they indicate reactivity and the extent of stability; metal complexes represent higher reactivity than the organic molecule in binding to biological targets.…”