Synthesis, Characterization, Optical, DFT, TD DFT Studies and in Silico ADME Predictions of Thiosemicarbazone Ligand and its Au(III) Complex

In the present work the reaction of hydrazone ligand with AuCl3 was investigated. The ligand that could be obtained by the condensation of Thiosemicarbazide with p-diaminobenzaldehyde belong to the class of mononegative or binegative bidentate ligands. The structure of the prepared samples has been defined by infrared spectroscopy, elemental analyzes, 1H-13C NMR, SEM, and Powder XRD techniques. The ligand is present in both solid and liquid states in the thione form. The ligand is binding to Au via azomethine nitrogen and thione sulfur atoms. Powder XRD pattern of ligand and [AuHLCl2]Cl complex show several diffraction peaks with high intensity indicating the crystalline nature of them. The observation of new diffraction peaks at different positions indicates the successful formation of the complex. The synthesized ligand and complex have crystallites sizes of 103 and 46 nm, respectively indicating the nanostructure of them. The ligand and it complex shows different particles shapes of plates, sheets, and spheres. Optimizations of the geometries of the formed complex with gold and the ligand were carried out by using DFT in a gaseous state. The excited states of various multiplicities were examined by the TD-DFT.