Study of molecular structure, anharmonic vibrational dynamic and electronic properties of sulindac using spectroscopic techniques integrated with quantum chemical calculations

Abstract

In the present investigation, spectroscopic techniques (FTIR, FT-Raman and UV–Vis) and quantum chemical calculations are employed for exploring vibrational and electronic spectra of sulindac compound. The calculations are performed on most stable conformer of the sulindac molecule using density functional theory (DFT). Anharmonic corrections are made to frequencies using vibrational second-order perturbation theory (VPT2). The effect of intermolecular interactions on the vibrational dynamics has been analyzed using dimeric structure of sulindac molecule. Hirshfeld surface analysis and 2D fingerprint plots are utilized to investigate the nature of interaction present in the crystal system. To account for electronic spectra in different solvents, an integral equation formalism of polarizable continuum model (IEFPCM) at TD-DFT/B3LYP/6-31G(d,p) level of theory has been employed. An excellent agreement between the theoretical and experimental data over the entire spectral region is observed. In addition, natural bond orbital (NBO) analysis, frontier molecular orbitals, nonlinear optical properties (NLO) and molecular electrostatic potential (MEP) analysis are also reported.