Vibrational spectroscopic studies and Natural Bond Orbital analysis of 4,6-dichloro-2-(methylthio)pyrimidine based on density functional theory

The FT-IR and FT-Raman spectra of 4,6-dichloro-2-(methylthio)pyrimidine (DMP) have been recorded and analyzed. The optimized geometry, intramolecular hydrogen bonding, and harmonic vibrational wave numbers of DMP have been investigated with the help of B3LYP density functional theory (DFT) method supplemented with 6-31G** basis set. The infrared and Raman spectra were predicted theoretically from the calculated intensities. Natural Bond Orbital (NBO) analysis of DMP has been performed to indicate the presence of intramolecular C–H⋯Cl hydrogen bonding. The formation of Lewis and non-Lewis orbitals and second-order perturbation energies of DMP have also been reported.

Pyrimidine and its derivatives are known for their biological and pharmaceutical importance. They are belongs to the family of nucleic acids. Nucleic acids are of great interest, since they control the manufacture of protein and functions of the cell in living organisms. Due to the significant role of N-heterocyclic molecules in the structural problems of nucleic acid investigation on substituted pyrimidines draws considerable attention.Figure optionsDownload as PowerPoint slideHighlights
► The FT-IR and FT-Raman spectra of 4,6-dichloro-2-(methylthio)pyrimidine studied.
► A comparison with the IR and Raman spectra of 4,6-dichloro-2-(methylthio)pyrimidine have been reported NBO analysis shows the improper weak C–H⋯Cl hydrogen bond.