Corrosion Inhibition of Aluminium in Gas and Acid Media by Some Chalcone-Based N-(3-Aminopropyl)Imidazoles: TD-DFT-Based FMO, Conceptual DFT, QTAIM and EDA Studies

Fritzgerald Kogge Bine,Stanley Numbonui Tasheh,Nyiang Kennet Nkungli

doi:10.4236/cc.2021.91003

Fritzgerald Kogge Bine, Stanley Numbonui Tasheh + Show 1 more

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https://doi.org/10.4236/cc.2021.91003

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Journal: Computational Chemistry	Publication Date: Jan 1, 2021
Citations: 3	License type: CC BY 4.0

Abstract

The efficacy and mode of action of five chalcone-based imidazole derivatives as corrosion inhibitors of aluminium metal in gas-phase and acidic medium have been investigated herein via quantum chemical calculations. Dispersion-corrected DFT (DFT-D3) and time-dependent DFT (TD-DFT) calculations were performed at PBE0/def2-TZVP//PBEh-3c and CAM-B3LYP/def2- TZVP levels of theory, respectively. Conceptual DFT, the quantum theory of atoms-in-molecules (QTAIM) and local energy decomposition (LED) analyses have been performed. The LED analysis was performed at the coupled-cluster singles and doubles with perturbative triples (CCSD(T))/def2-SVP level of theory. Frontier molecular orbital energy gaps calculated using the TD-DFT method are found to lie in the range 3.574 - 4.444 eV, indicative of good adsorption and corrosion inhibition efficacies of the investigated molecules. The interactions between aluminium and the inhibitor molecules studied are found to be energetically favorable, owing to negative computed interaction energy values. Furthermore, QTAIM analysis revealed metal-carbon, metal-oxygen and metal-nitrogen interactions in the inhibitor-aluminium complexes, which are predominantly electrostatic in character, according to LED analysis results. Calculated proton affinities (PAs) have revealed the anticorrosion potentials of the investigated inhibitors in acidic medium, with a noticeable dependency on temperature within the range 273.15 - 343.15 K.

Highlights

In recent times, considerable research attention is focused on the design and synthesis of organic molecules as corrosion inhibitors for metals and their alloys
The commonly used Kohn-Sham density functional theory (DFT) (KS-DFT) provides the best cost-accuracy ratio in the calculation of molecular orbital energies, it may fail to predict highly accurate molecular orbital energies [32]. This is true for the LUMO eigenvalue and the HOMO-LUMO gaps, reason being that KS-DFT is essentially a workhorse for ground state properties, by means of which the accurate computation of virtual LUMO orbitals is not guaranteed [32]
Computed values of the frontier molecular energy gaps in gas phase are in the range 3.574 eV and 4.444 eV, which are found to be lower than similar values in the literature, suggestive of very good adsorptive and inhibition capacity [5]

Summary

Introduction

Considerable research attention is focused on the design and synthesis of organic molecules as corrosion inhibitors for metals and their alloys. Upon adsorption on a metal surface, electrons are transferred from an organic inhibitor to vacant orbitals of a metal, leading to covalent and/or non-covalent interactions (closed shell interactions) between the metal and the inhibitor. The need to choose corrosion inhibitors that are nontoxic and eco-friendly cannot be underestimated. In this regard, chalcones and their derivatives have drawn much interest, owing to their high tolerance in the human body (especially when complexed with metals) [6] [7]. Environmental pollution by inorganic corrosion inhibitors has prompted the search for green organic corrosion inhibitors that are biodegradable and do not contain heavy metals or other toxic constituents

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