Reactivity and Fe-complexation investigation by computational simulation studies on phenyltetrazole derivatives as mild steel corrosion inhibitors in aqueous acidic medium

B3LYP, B3PW91, CAM-B3LYP, HCTH, omega B97XD, and M06-2X are six hybrid correlation-exchange and meta-GGA functionals, with 6-31G(d,p) basis set for the H, C, N, O and Cl atoms and the LANL2DZ basis set for the Fe atom. Utilized to determine the most favorable to be applied with phenyltetrazole derivatives, namely: 5-phenyl-1H-tetrazole (Ph-T), 5-p-tolyl-IH-tetrazole (Me-Ph-T), 5-(4-methoxyphenyl)-1H-tetrazole (Me-O-Ph-T), 5-(4-chlorophenyl)-1H-tetrazole (Me-O-Ph-T), and 5-(4-chlorophenyl) (CI-Ph-T). Aside from that, the quintet complexes were the most stable of the spin multiplicities studied. Furthermore, three forms of interactions between Fe and phenyltetrazole compounds are identified using Fukui functions, including Fe-Me/Me-O/CI, Fe-O, and Fe-N among eleven complexes. The meta-GGA functionals are ideally suited to predict metal-ligand interaction in the complexes investigated, which contain the transition metal iron with unsaturated valences. While the bond energies and enthalpies estimated for the two Fe-Me-O-Ph-T and Fe-CI-Ph-T complexes are the lowest and almost identical, the two inhibitors investigated act similarly. Furthermore, chemisorption is promoted by the flatness of the CI-Ph-T and Me-O-Ph-T inhibitors. Moreover, the adsorption energy of the CI-Ph-T and Me-O-Ph-T inhibitors (-185.661 and -186.005 kcal/mol, respectively), suggests that they are the most stable and strongest adsorption systems demonstrated by MDS. The discovered dynamic descriptors were in excellent accord with the quantum study's findings. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study investigates the interaction between phenyltetrazole derivatives and iron using different density functional methods and basis sets. The results show that meta-GGA functionals are suitable for predicting metal-ligand interactions in the complexes. The interaction between iron and phenyltetrazole compounds occurs mainly through Fe-Me/Me-O/CI, Fe-O, and Fe-N interactions. The inhibitors CI-Ph-T and Me-O-Ph-T have low bond energies and enthalpies, and exhibit similar modes of action. The high adsorption energy of CI-Ph-T and Me-O-Ph-T inhibitors suggests that they are the most stable and have the strongest adsorption.