Vol. 3, Issue 3 (2018)
Quantum mechanical calculations and spectroscopic investigation (FTIR, FT-Raman and UV-Visible) on (6R, 7R)-7-[(2Z)-2-(2-amino-1, 3-thiazol-4-yl)-2-[(carboxymethoxy) imino] acetamido]-3-ethenyl-8-oxo-5-thia-1-azabicyclo [4.2.0] oct-2-ene-2-carboxylic acid: a Pharmaceutical drug using Density functional theory
Author(s): P Manjusha, Johanan Christian Prasana, S Muthu
Abstract: Fourier transforms infrared (FT-IR) and FT Raman (FT-RS) and UV-Visible spectra of (6R,7R)-7-[(2Z)-2-(2-amino-1,3-thiazol-4-yl)-2-[(carboxymethoxy)imino]acetamido]-3-ethenyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid (Cefixime)were recorded and analyzed. Using density functional theory (DFT) calculation (B3LYP) with standard 6-311++G (d,p) basis set the molecular geometry vibrational frequencies, infrared intensities, Raman activity were calculated. The observed FT-IR and FT-Raman data were used to carry out the complete vibrational assignment and analysis of the functional modes of the compound. The thermodynamic functions of Cefixime drug were also performed by B3LYP with basis set 6-311++G(d,p).Potential Energy Distribution (PED) values and the HOMO and LUMO energy gap levels that the energy gap reflects the chemical activity of the molecule and compared with UV Absorption spectra. The Molecular Electrostatic Potential (MEP) mapped onto an isodensity surface has been obtained.