Syntheses, spectroscopic investigation and electronic properties of two sulfonamide derivatives: A combined experimental and quantum chemical approach

• Two sulfonamide derivatives were synthesized and characterized by spectroscopic techniques.
• The structures were further studied using DFT calculations to provide structural and spectroscopic information and guide spectral assignments.
• The computed electronic and spectroscopic properties were compared with the experimental results.
• The electronic properties predict the large intramolecular charge transfer in the molecules and significant substitution effects.

Two sulfonamides derivatives, N-phenethyl-4-methylbenzenesulfonamide (1) and N-(4-hydroxyphenethyl)-4-methylbenzenesulfonamide (2), were successfully synthesized and fully characterized using 1H NMR, 13C NMR, FT–IR spectroscopies and elemental analysis. The molecular and electronic structures of the compounds were further investigated using density functional theory calculation at B3LYP and B3PW91 functionals using 6–311++G(d,p) basis set to provide structural and spectroscopic information and guide spectral assignments. The experimental and simulated 1H NMR, 13C NMR and FT–IR spectra were compared and the accuracy was discussed. The conformational analysis was performed in order to find the most stable molecular structure of the compounds. Molecular quantities such as ionization potential, electron affinity, electronegativity, electrophilicity index and chemical hardness and softness were calculated and used as an additional molecular characteristic to predict the stability of the molecules. Electronic properties such Mullikan atomic charges, HOMO, LUMO and HOMO–LUMO energy gaps and molecular electrostatic potential maps predict the large intramolecular charge transfer within the molecules and significant substitution effects.

The experimental and calculated FT–IR spectra of N-(4-hydroxyphenethyl)-4-methylbenzenesulfonamide (2). The calculated spectra was simulated using harmonic force field calculations at B3LYP/6–311++G(d,p) with Gaussian lineshape and 15 cm−1 of half-width at half-height.Figure optionsDownload as PowerPoint slide