Molecular structure, vibrational spectra, UV–vis, NBO, and NMR analyses on nevirapine using ab initio DFT methods

Abstract

Nevirapine is an anti-human immunodeficiency virus (HIV) agent that belongs to the class of the non-nucleoside inhibitors of the HIV-1 virus reverse transcriptase. Spectral characteristics of nevirapine have been probed into by methods of Fourier transform infrared (FTIR), FT-Raman, UV-visible, and quantum chemistry. The UV spectrum was measured in methanol. In order to gain some valuable insight into the recorded spectrum, the quantum mechanical calculations were performed for nevirapine using both ZINDO and time-dependent density functional theory at B3LYP/6-31G(d,p) level. The optimized molecular geometry, bond orders, natural bond order analysis, and harmonic vibrational wavenumbers of nevirapine were calculated by restricted Hartree-Fock and density functional B3LYP methods with the 6-31G(d,p) basis set using Gaussian 03 W program. The harmonic vibrational frequencies calculated have been compared with experimental FTIR and FT-Raman spectra. The restricted Hartree-Fock and density functional theory-based nuclear magnetic resonance (NMR) calculation procedure was also performed, and it was used for assigning the 13C and 1H NMR chemical shifts of nevirapine.