Síntese e caracterização de complexos de paládio(ii) contendo ligantes imínicos. Aspectos estruturais e potencialidades leshmanicidas

Abstract

Cyclopalladates and cycloplatinates have been the subject of many recent studies due to their cytotoxic activities against tumor cells comparable to cisplatine and carboplatine. Cyclopalladated compounds, in particular, are extensively studied because of their high stability and effective action of their drugs in low concentration in the organism. In addition to having a considerably smaller cytotoxicity than the analogous platinum compounds, these compounds can generate drugs with lower final cost because palladium is cheaper than platinum. The aim of this work was the synthesis of new palladium(II) complexes, using a Schiff base, previously synthesized as a ligand. The synthesized compounds were characterized by elemental analysis, infrared and ultraviolet-visible region spectroscopies, thermal analysis (TG-DTA) and nuclear magnetic resonance 1H and 13C. Other techniques such as melting point and solubility tests were carried out. A square-planar coordination geometry, characteristic for Pd(II) was observed for all complexes. Spectroscopy in the infrared region was of great value to diagnose the mode of coordination compounds. Thermal studies was used to collect information about the stoichiometry of each organometallic compound, as well as to establish an order of thermal stability of the complexes of the series. NMR spectroscopy showed the formation of the cyclometallated ring, as well as coordination of the ligands. Leishmania species behave in a similar manner to tumor cells when compared to drug susceptibility and cell proliferation, the synthesized compounds were tested in biological assays against Leishmania where in vitro experiments with (L.) brasilienses promastigote cells were performed, and the imine ligand showed the best results.