Síntese e caracterização de complexos de paládio (ll) com iminas: aspectos e estruturais e atividade citotóxica em adenocarcinoma mamário humano

Abstract

This work presents the synthesis, structural characterization and verification of anticarcinogenic activity of five new mononuclear complexes of palladium(II) from the ligand N,N’-Bis[4-(dimethylamino)benzylidene]-ethane-1,2-diamine (p-diben). The ligand is reacted with one-pot synthesized Li2[PdCl4] to give compound [PdCl2(p-diben)]. The chlorides of this compound were substituted regiospecifically by pseudohalides and halides, by reaction with NaN3, KNCO, KBr e and KI forming the compounds [Pd(N3)2(p-diben)], [Pd(NCO)2(p-diben)], [PdBr2(p-diben)] and [PdI2(p-diben)], respectively. All compounds were characterized by infrared vibrational and UV-Vis electronic spectroscopies, elemental analysis, 1H and 13C nuclear magnetic resonance, thermal analysis and, only to compound [Pd(N3)2(p-diben)], single crystal X-ray diffraction. The results indicate the formation of the N,N-chelated products, where palladium(II) binds by imines nitrogen. Furthermore, coordination causes a decrease in the double bond character of C=N, facilitating rotation to minimize the steric hindrance. This effect is referred to as imine E/Z isomerization. All the complexes and ligand p-diben were tested for DNA interaction and modification of cell morphology of human breast adenocarcinoma MCF-7 cells. It was found that the free ligand did not show significant effect on the mentioned cells and showed results for the DNA interaction comparable to the negative control. The synthesized complexes showed cytotoxic potential across the MCF-7 cells. Compounds [PdCl2(p-diben)] and [Pd(NCO)2(p-diben)] showed qualitative cytotoxicity greater than that of cisplatin. For DNA interaction, the compound [Pd(NCO)2(p-diben)] stood out, indicating that a possible action mechanism of this compound is direct DNA binding.