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

Abstract

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

In Silico and In Vitro Analyses to Repurpose Quercetin as a Human Pancreatic α-Amylase Inhibitor

“…Conversely, the red coloration indicates a negative region, which is indicative of an electrophilic attack. The green coloration, on the other hand, represents areas of zero potential within the molecule …”

“…The green coloration, on the other hand, represents areas of zero potential within the molecule. 54 The study revealed that oxygen atoms exhibited negative charges, whereas hydrogen atoms that formed bonds with oxygen or nitrogen atoms exhibited positive charges. The negative and positive centers played a crucial role in the establishment of noncovalent interactions between ligands and receptors throughout molecular docking and MD simulations.…”

Green electrochemical nanosensor platform design for mexiletine detection based on Citrus reticulata peel-mediated iron nanoparticles and quantum dots and investigation of the adsorption mechanism by the DFT-D3 method

“…78,79 According to HOMO-LUMO analysis, the band gap energies were calculated as 2.26 eV in the gas phase and 1.93 eV in the solvent medium (Table 3). The electrophilicity index (o) with the value of 9.16 eV in the gas phase belongs to the classification of organic molecules that have the strong electrophiles with o 4 1.5 eV, 80 as observed in the solvent phase. It is seen that the charge distribution in the LUMO is concentrated on the iron oxide moiety, whereas the HOMO is localized on CQDs (Fig.…”

Synthesis, characterization, and biological activity using computational study of synthesized monocyclic β-lactam ligands

“…Molecular electrostatic potentials (MEPs) depict the distribution of charges in the ground state of molecules across their entire energy surface [68]. These are extremely important for understanding the electronic structure of molecules at the molecular level [69]. MEPs provide a useful approach for identifying the relative polarity of molecular species through color shading, making them an effective tool for exploring the structure-property relationship.…”