Vibrational spectroscopic [FT-IR, FT-Raman] investigation on (2,4,5-Trichlorophenoxy) Acetic acid using computational [HF and DFT] analysis

Abstract

In the present methodical study, FT-IR, FT-Raman and NMR spectra of the (2,4,5-Trichlorophenoxy) Acetic acid are recorded. The observed fundamental frequencies (IR and Raman) are assigned according to their distinctiveness region. The hybrid computational calculations are carried out by HF and DFT (B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets and the corresponding results are tabulated. The impact of the presence of tri-chlorine atoms in phenyl structure of the compound is investigated. The vibrational sequence pattern of the molecule related to CH2COOH is analyzed. Moreover, 13C NMR and 1H NMR are calculated by using the gauge independent atomic orbital (GIAO) method with B3LYP methods and the 6-311++G(d,p) basis set and their spectra are simulated and the chemical shifts related to TMS are compared. A study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, are performed by HF and DFT methods. The Kubo gap of the present compound is calculated related to HOMO and LUMO energies which confirm the occurring of charge transformation between the base and ligand group. Besides frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) was performed. NLO properties related to Polarizability and hyperpolarizability are also discussed.