Quantum chemical calculation studies on 4-phenyl-1-(propan-2-ylidene)thiosemicarbazide

Ab initio calculations of the structure, atomic charges, natural bond orbital, and thermodynamic functions have been performed at HF/6- 311G** and B3LYP/6-311G** levels of theory for the title compound of 4-phenyl-1-(propan-2- ylidene) thiosemicarbazide. The calculated results show that the sulfur atom and all of the nitrogen atoms have bigger negative charges and they are the potential sites to react with the metallic ions, which make the title compound become a multidentate ligand. The coordination ability of the sulfur atom and the nitrogen atom of C=N double bond will increase with the increase of the polarity of the solvent. Electronic absorption spectra have been calculated by time-dependent density functional theory (TD-DFT) method. The calculation of the second-order optical nonlinearity also has been carried out, and the molecular hyperpolarizability is 3.068 x 10(-30) esu.