Quantum mechanical calculations and spectroscopic (FT-IR, FT-Raman and UV) investigations, molecular orbital, NLO, NBO, NLMO and MESP analysis of 4-[5-(4-methylphenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl] benzene-1-sulfonamide

Abstract

The molecular structural parameters and vibrational frequencies of the fundamental modes of 4-[5-(4-methylphenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl] benzene-1-sulfonamide(abbreviated as 4MPTFM1HPB1SA) have been obtained using Density functional theory (DFT) technique in the B3LYP approximation with 6-311G(d,p) and 6-311++G(d,p) basis sets. Detailed vibrational assignments of the observed FT-IR and FT-Raman bands have been proposed on the basis of potential energy distribution (PED). The difference between the observed and the calculated wavenumbers values are very small. The theoretically predicted FT-IR and FT-Raman spectra of the title molecule have been constructed. The molecular electrostatic potential has been mapped primarily for predicting sites and relative reactivities toward electrophilic and nucleophilic attack. The intramolecular contacts have been interpreted using Natural Bond Orbital (NBO) and Natural Localized Molecular Orbital (NLMO) analysis. Important non-linear properties such as electric dipolemoment and first hyperpolarizability of 4MPTFM1HPB1SA have been computed using B3LYP quantum chemical calculation. The absorption wavelength, energy and oscillator’s strength are calculated by TD-DFT and 4MPTFM1HPB1SA is approach complement with the experimental findings.The temperature dependence of thermodynamic properties has been analyzed. The Natural charges, Frontier molecular orbitals (FMOs), chemical hardness (η), chemical potential (μ), Electro negativity (χ) and electrophilicity values (ω) are calculated and reported.