Study of vibrational spectra and hydrogen bonding network in dimeric and tetrameric model of ampicillin using DFT and AIM approach
| Autor: | Anuradha Shukla, Kirti Sinha, Poonam Tandon, Eram Khan |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Hydrogen bond
Stereochemistry Organic Chemistry Binding energy Intermolecular force 02 engineering and technology biochemical phenomena metabolism and nutrition 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Potential energy 0104 chemical sciences Analytical Chemistry Inorganic Chemistry chemistry.chemical_compound Crystallography Monomer chemistry Electrophile Molecule 0210 nano-technology Spectroscopy Natural bond orbital |
| Zdroj: | Journal of Molecular Structure. 1131:225-235 |
| ISSN: | 0022-2860 |
| Popis: | Ampicillin is a β-lactam antibiotic that is active against both gram-positive and gram-negative bacteria and is widely used for the treatment of infections. In this work, molecular properties of ampicillin are calculated on the basis of calculations on its dimeric and tetrameric models using DFT/B3LYP/6-311G(d,p). HOMO-LUMO energy gap shows that chemical reactivity of tetrameric model of ampicillin is higher than the dimeric and monomeric model of ampicillin. To get a better understanding of intra and intermolecular bonding and interactions among bonds, NBO analysis is carried out with tetrameric model of ampicillin, and is further finalized with an ‘quantum theory of atoms-in-molecules’ (QTAIM) analysis. The binding energy of dimeric model of ampicillin is calculated as −26.84 kcal/mol and −29.34 kcal/mol using AIM and DFT calculations respectively. The global electrophilicity index (ω = 2.8118 eV) of tetrameric model of ampicillin shows that this behaves as a strong electrophile in comparison to dimeric and monomeric model of ampicillin. The FT-Raman and FT-IR spectra were recorded in the solid phase, and interpreted in terms of potential energy distribution analysis. A collective theoretical and experimental vibrational analysis approves the presence of hydrogen bonds in the ampicillin molecule. |
| Databáze: | OpenAIRE |
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