X-ray structures and spectroscopic properties of chiral thiosemicarbazides as studied by computational calculations

<p></p> <p>In the present work, (+)-(<i>R</i>)-1-[2-(benzenesulfonamido)-3-phenylpropanoyl]-4-[(4-methoxy)phenyl]thiose micarbazide (<b>1a</b>) and (−)-(<i>S</i>)-1-[2-(benzenesulfonamido)-3-phenylpropanoyl]-4-[(4-methoxy)phenyl] thiosemicarbazide (<b>1b</b>) were synthesized starting with <i>D</i>-phenylalanine methyl ester and <i>L</i>-phenylalanine ethyl ester as a source of chirality. The single crystal structures were characterized by XRD, FTIR and <sup>1</sup>H and <sup>13</sup>C NMR spectroscopy. Density functional theory (DFT) calculations (B3LYP/6-311G(d,p) were carried out to obtain the ground state optimized geometry, the IR and the NMR spectra of the molecule. Electronic properties (HOMO&LUMO) were calculated using the Time Dependant-DFT/B3LYP/6-311G(d,p) method. Furthermore, NBO, MEP, and Fukui function analyses have been used for the quantitative determination of the chemical activities at various sites of the molecule.</p>