Application of Quantum Mechanical Calculations and Symmetry in Chemistry; Vibration Frequencies, Corrosion Inhibition and Prodrugs
The principles of nature are the sole foundation for ab initio quantum chemistry: Molecular modelling methods that can accurately predict structures, energetics, reactivity, and other features of molecules have been created over the last two decades. Computational chemistry does not replace experimental studies, but it does play an important role in chemists’ ability to:
Many molecular properties, such as bond energies and reaction energies, structures of ground-excited-and transition-states, atomic charges and electrostatic potentials, vibrational frequencies (IR and Raman), transition energies and intensities for UV and IR spectra, NMR chemical shifts, and dipole moment, can be computed.
This book was focused on three applications to show the importance of quantum chemistry calculations in chemical applications supporting experimentation.
The first application was for the electrical, chemical, vibration frequencies, and absorption intensities of SWCNTs, which differ greatly depending on symmetry, chirality, and diameter, necessitating experimental evaluation of these structural parameters. The vibrational density of states, especially at low frequencies, gives information about the structure of carbon nanotubes. Significant differences in the frequencies and relative intensities of these peaks provide a method for distinguishing between structurally different nanotubes. Experiments can now yield additional structural information thanks to our findings.
The second application involves calculating the geometrical structure, physical properties, and inhibition efficiency parameters of new organic compounds as inhibitors against carbon steel corrosion in acidic or basic solutions using the quantum mechanical method of PM3 and Density Functional Theory (DFT) of B3LYP with a level of 6-311++G (2d, 2p) in a simulated environment. The findings were in line with the experimental percent IE. Mulliken charges population analysis was used to investigate local reactivity. The third use involves adopting recommended novel prodrug designs to increase active drug solubility and thus bioavailability, increase permeability and absorption, and change the drug’s distribution profile for improved efficacy, reduced toxicity, and adverse effects. Over time, new pharmacological therapy advances have become increasingly complex, time-consuming, and expensive. The Gaussian 09 programme was used to execute a computational method in our prodrug design. The total energy of the reactants was compared to the energies and transitional stages up to the final products. The goal of the theoretical study of the suggested primary pharmaceuticals is to see whether there are any ways to improve the qualities of prodrugs and if there are any new alternatives to approved prodrugs. Correlations between experimental and calculated data were used to verify and ensure that the final results could be used.
Rehab Majed Kubba
Department of Chemistry, College of Science, University of Baghdad, Baghdad, Iraq.