Molecular geometry, vibrational spectra, atomic charges, frontier molecular orbital and Fukui function analysis of antiviral drug zidovudine

The solid phase FT-IR and FT-Raman spectra of zidovudine (AZT) were recorded in the regions 4000–400 and 3500–100 cm−1, respectively. The optimized geometry, frequency and intensity of the vibrational bands of zidovudine were obtained by the Restricted Hartree–Fock (RHF) density functional theory (DFT) with complete relaxation in the potential energy surface using 6-31G(d,p) basis set. The harmonic vibrational frequencies for zidovudine were calculated and the scaled values have been compared with experimental values of FTIR and FT-Raman spectra. The observed and the calculated frequencies are found to be in good agreement. The harmonic vibrational wave numbers and intensities of vibrational bands of zidovudine with its cation and anion were calculated and compared with the neutral AZT. The DFT calculated HOMO and LUMO energies shows that charge transfer occurs within the molecule. The electron density-based local reactivity descriptors such as Fukui functions were calculated to explain the chemical selectivity or reactivity site in AZT.

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► The solid phase FTIR and FT-Raman spectra of AZT were recorded and analyzed.
► The optimized geometry and vibrational wavenumbers were computed using ab initio HF and DFT methods.
► The complete vibrational assignment and spectroscopic analysis have been carried out.
► The DFT calculated HOMO and LUMO energies show that charge transfer occurs within molecule.
► The Fukui functions were calculated to explain the chemical selectivity or reactivity site in AZT.