Synthesis, structural, spectroscopic studies, NBO analysis, NLO and HOMO–LUMO of 4-methyl-N-(3-nitrophenyl)benzene sulfonamide with experimental and theoretical approaches

The sulfonamide compound, 4-methyl-N-(3-nitrophenyl)benzene sulfonamide (abbreviated as 4M3NPBS) has been synthesized and characterized by FTIR, FT-Raman NMR, single crystal X-ray diffraction and thermal analysis. Density functional (DFT) calculations have been carried out for the title compound by performing DFT level of theory using B3LYP/6-31G(d,p) basis set. The calculated results show that the predicted geometry can well reproduce the structural parameters. Predicted vibrational frequencies have been assigned and compared with the experimental IR spectra and they support each other. The UV–Vis spectrum of the compound was recorded. The theoretical electronic absorption spectra have been calculated by using CIS, TD-DFT, ZINDO methods. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The first order hyperpolarizability (β0) of 4M3NPBS was calculated using B3LYP/6-31G(d,p) method on the basis of finite-field approach. In addition, frontier molecular orbitals and molecular electrostatic potential were carried out by using density functional theory (DFT/B3LYP) 6-31G(d,p) basis set. The calculated HOMO and LUMO energies show that charge transfer occur in the molecule. The thermal stability of the title compound was determined with the aid of thermo gravimetric analysis (TGA) and differential thermal analysis (DTA).

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A detailed interpretation of Infrared and Raman spectra of 4M3NPBS were reported. ► Electronic absorption spectra and lower HOMO–LUMO energy gap indicates electronic transition of 4M3NPBS. ► 4M3NPBS exhibited good NLO activity. ► Isotropic chemical shifts (13C and 1H NMR) were calculated using the GIAO method.