FT-IR and computational study of (E)-N-carbamimidoyl-4-((2-formylbenzylidene)amino)benzene sulfonamide

The infrared spectrum of (E)-N-carbamimidoyl-4-((2-formylbenzylidene)amino)benzene sulfonamide has been recorded and analysed. Geometry and harmonic vibrational wavenumbers were calculated theoretically using Gaussian 03 set of quantum chemistry codes. Calculations were performed at the Hartree–Fock and DFT levels of theory using the standard 6-31G∗ basis. The calculated wavenumbers (B3LYP) agree well with the observed wavenumbers. The data obtained from vibrational wavenumber calculations are used to assign vibrational bands found in infrared spectrum of the studied molecule. The red-shift of the NH stretching band in the infrared spectrum from the computed wavenumber indicates the weakening of the NH bond. The NH stretching band has split into a doublet 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 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.