Structural , Spectroscopic Investigation and Quantum Chemical Calculation Studies of 2 , 4 , 6 - trimethylphenol for Pharmaceutical Application

The FTIR and FT-Raman spectra of 2,4,6-trimethylphenol (TMP) have been recorded in the regions 4000-400 cm and 3500-50 cm, respectively. The optimum molecular geometry, harmonic vibrational frequencies, infrared intensities and Raman scattering activities were calculated by ab initio Hartree–Fock (HF) and density functional theory (DFT/B3LYP) methods using 6-31+G(d,p) basis set. The normal modes are assigned with the help of total energy distribution (TED) analysis. The observed vibrational wavenumbers were compared with the calculated results. The difference between the observed and scaled wavenumber values of most of the fundamentals is very small. The calculated first hyperpolarizability results show that TMP may have microscopic nonlinear optical (NLO) behavior with non-zero values. The effects of frontier orbitals, HOMO and LUMO, transition of electron density transfer have been discussed. Besides, molecular electrostatic potential (MEP), Mulliken’s charges analysis, and several thermodynamic properties were performed.