Theoretical Investigation to Corrosion Inhibition Efficiency of Some Chloroquine Derivatives Using Density Functional Theory

Abstract

In this work, the potential of corrosion inhibition of four chloroquine derivatives; <em>N⁴</em>-(7-Chloroquinolin-8-ol-4-yl)-<em>N¹</em>,<em>N¹</em>-diethylpentane-1,4 diamine (M₂), <em>N⁴</em>-(7-Chloroquinolin-8-amino-4-yl)-<em>N¹</em>,<em>N¹</em>-diethylpentane-1,4 diamine (M₃) and <em>N⁴</em>-(5-bromo-7-Chloroquinolin-8-amino-4-yl)-<em>N¹</em>,<em>N¹</em>-diethylpentane-1,4-diamine (M₄) were investigated. Their chemical descriptors which include molecular volume, softness, chemical hardness, electronegativity, fraction (ΔN) and electrophilicity index (<em>ω</em>) dipole moments, surface of the molecule, and electronic parameters which include the E_HOMO (the highest occupied molecular orbital of energy); E_LUMO (lowest unoccupied molecular orbitals of energy) and energy gap (E_LUMO-E_HOMO) were calculated using the DFT/B3LYP/6-311 G approach. The results revealed an established correlation between the electronic structures and the quantum parameters of the studied molecules together with their inhibition efficiency toward corrosion process. Also chloroquine derivatives with –NH₃ substituent: M₃ and M₄ were predicted to have enhanced inhibition efficiency.