Synthesis, spectroscopic characterization, crystal structure and computational studies of two new N-aroyl-N′-(2,4,6-tribromophenyl)thioureas

Abstract

Two new compounds, N-benzoyl-N'-tribromophenylthiourea (I) and 4-nitrobenzoyl-N'-tribromophenylthiourea (II), were synthesized and characterized by 1H NMR, 13C NMR, IR, and X-ray single crystal diffraction techniques. The molecular geometry of compounds I and II in the ground state has been calculated by using the density functional theory (DFT) method with the B3LYP/6-311G(d,p) basis set and compared with the experimental data. The calculated results show that the optimized geometry can reproduce well the crystal structural parameters. A detailed vibrational spectral analysis has been carried out, and assignments of the observed fundamental bands have been proposed on the basis of peak positions. The scaled theoretical frequencies show very good agreement with the experimental values. Frontier molecular orbitals energies (HOMO and LUMO), energy gap, and global chemical reactivity parameters such as ionization potential, electron affinity, chemical hardness, and chemical softness have been calculated, and the sites of electrophilic and nucleophilic regions where the molecular interactions likely to happen are identified. The molecular electrostatic potential and thermodynamic properties of the title compounds were investigated by theoretical calculations.