FT-IR, FT-Raman spectroscopy and computational study of N-carbamimidoyl-4-{[(E)-((2-hydroxyphenyl)methylidene]amino}benzenesulfonamide

The infrared and Raman spectra of N-carbamimidoyl-4-((2-hydroxybenzylidene) amino) benzenesulfonamide have been recorded and analyzed. Geometry and harmonic vibrational wavenumbers were calculated theoretically using Gaussian 03 set of quantum chemistry codes. Calculations were performed at the DFT (B3LYP) and MP2(SDD) levels of theory. The calculated wavenumbers (MP2) agree well with the observed wavenumbers. The data obtained from vibrational wavenumber calculations are used to assign vibrational bands found in infrared and Raman spectra of the studied molecule. The red-shift of the N–H stretching band in the infrared spectrum from the computed wavenumber indicates the weakening of the N–H bond. The N–H stretching bands has split into a doublet, 3453, 3427 and 3355, 3225 cm−1 in the IR spectrum owing to the Davydov coupling between neighboring units. The geometrical parameters of the title compound are in agreement with the reported similar derivatives. Calculated infrared intensities, Raman activities and the first hyperpolarizability are reported. The calculated first hyperpolarizability is comparable with the reported value of similar structures and may be an attractive object for further studies on non linear optics.