Jordaan M, Amide imidic prototropic tautomerization of efavirenz, NBO analysis, .pdf (2.3 MB)
Amide imidic prototropic tautomerization of efavirenz, NBO analysis, hyperpolarizability, polarizability and HOMO–LUMO calculations using density functional theory
journal contribution
posted on 2022-01-26, 08:08 authored by Maryam Amra Jordaan, Oluwakemi Ebenezer, Khethiwe Mthiyane, Nkululeko Damoyi, Michael Shapiensity functional theory (DFT) was performed in the gas phase to investigate the tautomerization and transi?tions in efavirenz. The amide and imidic tautomers’ geometrical parameters are performed using B3LYP/6-
31++G** and M06-2X/ cc-pVTZ (-F). The results showed that the amide tautomer is more stable than the imidic
tautomer in the gas phase. The non-linear optical (NLO) properties of the amide and imidic tautomers are
computed. Interestingly, the amide and imidic forms may be an attractive compound in enhancing NLO con?stituents due to their valuable non-linear property. Natural bond orbital (NBO) analyses have been performed on
the amide and imidic tautomers. The substantial differences in occupancies and the energies of bonding and anti?bonding orbital have been analyzed and described. Notably, thermodynamic (Gibbs free energy, entropy, and
enthalpy) properties of proton intra-migration of the tautomers via a single proton shift in the gas phase were
predicted. The detailed results revealed that the kinetic and thermodynamic favorability increased from imidic
tautomer to amide, hence the pathway to the amide arrangement of efavirenz is a favorable reaction. Besides
this, the electrostatic potential surface plots have been used to explore the possible site for electron-withdrawing
and donating. The frontier molecular orbital reveals the energy gap and chemical activity of the tautomers.