FT-IR, FT-Raman and computational study of (E)-N-carbamimidoyl-4-((4-methoxybenzylidene)amino)benzenesulfonamide.

The FT-IR and FT-Raman spectra of (E)-N-carbamimidoyl-4-((4-methoxybenzylidene)amino)benzenesulfonamide were recorded and analyzed. Geometry and harmonic vibrational wavenumbers were calculated theoretically using Gaussian 03 set of quantum chemistry codes. Calculations were performed at the Hartree-Fock (HF) and density functional theory (DFT) levels of theory. The calculated wavenumbers (B3LYP) agree well with the observed wavenumbers. Potential energy distribution is done using GAR2PED program. The red shift of the N-H stretching bands in the infrared spectrum from the computed wavenumber indicates the weakening of the N-H bond. The calculated first hyperpolarizability is comparable with the reported value of similar derivative and may be an attractive object for further studies of nonlinear optics. The variations in the CN bond lengths of the title molecule suggest an extended π-electron delocalization over the sulfaguanidine moiety which is responsible for the nonlinearity of the molecule. The geometrical parameters of the title compound are in agreement with that of reported similar derivatives.