Síntese e caracterização de complexos de cobre (II) e zinco (II) com ligantes aminados, potenciais agentes antiparasitários

Abstract

Several studies in the field of organic synthesis discuss the biological activity of diamine derivatives against various diseases, including Chagas disease and Leishmaniasis. Some of these compounds, however, are quite cytotoxic to the host, making their use not available for patients. In order to improve the biological activities of these substances, the synergistic effect resulting from the combination of these diamines with essential transition metals for our organism, such as copper and zinc, is applied. It is expected that this combination, in addition to enhancing the toxic effect under the parasites, may also decrease the toxicity of these compounds to the host. Based on this premise, the present work aimed to synthesize and characterize 8 mono- and disubstituted ligands derived from 1,2-ethylenediamine and 1,3-propanediamine, obtained through N-alkylation reactions of the respective diamines with 1-bromododecane and 1-bromodecane, and the synthesis and characterization of Cu (II) and Zn (II) metal complexes from the reactions between the ligands and the respective metal salts. The compounds presented here were characterized, when possible, by infrared (IV) and ultraviolet-visible (UV-Vis), mass spectrometry (MALDI-TOF), 1H and 13C nuclear magnetic resonance (NMR), elemental analysis of carbon, hydrogen and nitrogen (CHN) and X-ray crystallography. Ligands were obtained after purification by recrystallization or silica column chromatography (SCC) in satisfactory yields (47-63%). The metal complexes were obtained in moderate yields (14-65%) and their structures were proposed based on the analysis of all spectroscopic and analytical data and, in the case of metal complexes, by elucidating the crystal structure of their crystals (6e). Based on these analyses, it was proposed that these compounds are presented with octahedral geometry, coordinated to the metal ion, with the bidentate diamine ligands (chelate) and the auxiliary ligands (chloride, nitrate, acetate) in monodentate mode. Two series of these compounds were sent for biological assays against the parasites from both of the diseases proposed, and for other diseases. Previously reported results have shown that they have very promising activities against the parasites Leishmania amazonensis and Trichomonas vaginalis, which will possibly lead to the continuation of their studies.