DFT, NBO, Fukui Functions and Monte Carlo Studies on Quinoline Derivatives for Corrosion Inhibition Property

Abstract

The corrosion inhibiting property of 4-methylquinoline (4MQ) and 4-aminoquinaldine (4A2MQ) by using various quantum mechanical and molecular mechanics parameters such as EHOMO, ELUMO, energy difference (ΔEgap), electrophilicity, nucleophilicity, chemical hardness, chemical softness, adsorption energy on the metal surface, ability of back donation, electron affinity, chemical potential and dipole moment values are studied. Density functional studies were carried out using B3LYP/6-31g++(d,p), B3LYP/6-31g(d,p) and B3LYP/6-31g(d) basis sets. The outputs of the compounds were compared as well as the characteristics of the Fukui functions used to analyze them. The adsorption energy values were obtained using Monte Carlo simulation techniques. The adsorption energy calculations were carried out by using COMPASS force field and adsorption annealing methods. These calculated values had good agreement with previously reported values of these corrosion inhibitors. Comparing the combined dual descriptor values of 4MQ and 4A2MQ reveal that the latter compound readily undergoes electrophilic attack, leading to the enhanced corrosion inhibition. The efficiency of these corrosion inhibitors compounds by various studies was compared and the result shows that 4A2MQ can be better corrosion inhibitor than 4MQ.