Theoretical Calculation of Molecular Structure, Vibrational Spectra, and Molecular Electrostatic Potential of Metolazone

In the present investigation, a vibration spectral analysis was carried out using FT-Raman and FT-IR spectroscopy in the range 100-4000 and 400-4000 cm(-1) respectively, for 7-chloro-1,2,3,4-tetrahydro-2-methyl-3-(2-methylphenyl)-4-oxo-6-quinazoline sulfonamide (metolazone). The molecular structure, fundamental vibration frequencies, and intensity of the vibration bands are interpreted with the help of structure optimizations by density functional theory (DFT) types of the electronic structure method in the B3LYP/6-311++G(d,p) basis set. The results of the calculations were applied to simulated spectra of the title compound, which showed good agreement with observed spectra. The overestimations of the calculated harmonic wave numbers were efficiently corrected with the aid of a specific scaling procedure. A molecular electrostatic potential (MEP) map of the titled compound has been plotted in order to predict the electron rich and poor centers.