A DFT study of vibrational spectra of 5-chlorouracil with molecular structure, HOMO–LUMO, MEPs/ESPs and thermodynamic properties

• Published in: Polymer bulletin (Berlin, Germany) Vol. 80; no. 3; pp. 3055 - 3083
• Main Authors: Singh, J. S., Khan, Mohd. Shahid, Uddin, Saeed
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-03-2023; Springer Nature B.V
• Subjects: Biomolecules; Characterization and Evaluation of Materials; Charge distribution; Charge transfer; Chemistry; Chemistry and Materials Science; Complex Fluids and Microfluidics; Coronaviruses; Density functional theory; Drugs; Electron density; Energy gap; Geometry; Hydrogen; Mathematical analysis; Molecular orbitals; Molecular structure; Nitrogen; Normal distribution; Optimization; Organic Chemistry; Original Paper; Physical Chemistry; Polymer Sciences; Soft and Granular Matter; Stability analysis; Thermodynamic properties; Thermodynamics; Vibration mode; Vibrational spectra; MEPs/ESPs; Thermodynamics; DFT/G-09; Vibrational spectra; HOMO–LUMO
• ISSN: 0170-0839; 1436-2449
• DOI: 10.1007/s00289-022-04181-7

The density functional theory calculation has been carried out for the analysis of 5-chlorouracil using DFT/Gaussian 09 with GAR2PED. Recorded experimental spectra for Raman and IR of 5-chlorouracil have been analyzed all fundamental vibrational modes using the outcome results of DFT at 6-311++G** of Gaussian 09 calculations and the GaussView 5.09. To help the analysis of vibrational modes, GAR2PED program has been used in the calculation of PEDs. The charge transfer properties of 5-chlorouracil have been analyzed using HOMO and LUMO level energy analysis. HOMO and LUMO energy gap study supports the charge transfer possibility in molecule. These have been made to study for reactivity and stability of
heterocyclic molecules
for the analysis of antiviral drugs against the new corona virus: COVID-19. Here, the
smaller energy gap
of 5-chlorouracil is more responsible for charge transfer interaction in the
heterocyclic drug molecules
and a reason of more bioactivity. The electron density mapping within molecular electrostatic potential plot and electrostatic potential plotting within iso-surface plot have been evaluated the charge distribution concept in the molecule as the nucleophilic reactions and electrophilic sites. These computations have been used to produce the molecular charges, structure and thermodynamic functions of biomolecule. This study has been made to all internal modes of chloro group substituent at pyrimidine ring of C
5
atom. The splitting of frequencies has arisen in the two species for the normal distribution modes.
Graphical abstract