title: Molecular structure, harmonic and anharmonic frequency calculations of 2,4-dichloropyrimidine and 4,6-dichloropyrimidine by HF and density functional methods.
abstract: Quantum chemical calculations of energies, geometrical structural parameters, harmonic and anharmonic frequencies of 2,4-DCP and 4,6-DCP were carried out by HF and density functional theory methods with 6-311++G(d,p) as basis set. The assignment of each normal mode has been made using the observed and calculated frequencies, their IR and Raman intensities. A detailed interpretation of the FT-IR and FT-Raman spectra of 2,4-DCP and 4,6-DCP was reported on the basis of the calculated potential energy distribution (PED). A comparison of theoretically calculated vibrational frequencies at B3LYP/6-311++G(d,p) with FT-IR and FT-Raman experimental data shows good agreement between them. Natural atomic charges of 2,4-DCP and 4,6-DCP were calculated and compared with pyrimidine molecule.
authors.affiliation: Research and Development Centre, Bharathiar University, Coimbatore 641046, India.
authors.forename: Usha
authors.initials: U
authors.lastname: Rani
authors.forename: Halil
authors.initials: H
authors.lastname: Oturak
authors.forename: S
authors.initials: S
authors.lastname: Sudha
authors.forename: N
authors.initials: N
authors.lastname: Sundaraganesan
mesh_terms: D008956:Models, Chemical; D008968:Molecular Conformation; D011743:Pyrimidines / Q000737:chemistry*; D011789:Quantum Theory; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman / Q000379:methods*; D014732:Vibration
chemical_list: D011743:Pyrimidines; C513879:2,4-dichloropyrimidine