Quantochemical study of the thiosemicarbazone coordination and its methylated derivatives

Abstract

Thiosemicarbazone is a molecule containing the R1R2C=N-NR3-C (=S)-NR4R5 group. The sulfur and nitrogen atoms has some free electron pairs. Some thiosemicarbazone are known to have many medicinal properties. They are usually mediated by an association with copper or iron. Indeed transition metal complexes with given chemical structures are useful alternatives in the treatment of certain diseases since coordination of active ingredients deeply modifies both the physiological properties of metals and ligands in the meaning of overall improvement of these properties. The present investigation is a quantum study of the thiosemicarbazone complexation and its methylated derivatives. This study’s aim is to determine the most favorable coordination site of each of these ligands. On the basis of values of some coordination indicators (CI) it appears that the sulphur atom is the most favorable coordination site of the studied thiosemicarbazone. Complexes of these ligands with the Zn (II) were modeled. The calculations were made by the DFT / B3LYP method.