Síntese e caracterização de complexos de rutênio e cobalto com aminas cíclicas alifáticas: estudos de interação com metionina e DNA

Abstract

This thesis is an investigation of the interactions of Ru and Co complexes with biomolecules, such as nitrogenous bases and DNA, aiming at the development of metal-pharmaceuticals, using as co-ligands macrocycles and nitric oxide. The unpublished complexes synthesized were: cis-[Ru(dmso)2(Et-cyclen)]Cl, [Co(Met)L(mac)]n+ , cis-[Ru(Met)2(mac)]+ and [Ru(NO)(Met)(mac)]2+(with Et=ethil, mac=macrocycle and Met=methionine). Analysis of the vibrational spectra showed the appearance of bands characteristic of the methionine and macrocyclic ligands (cyclam / cyclen/ Et-cyclen), as well as allowed to assign the assignment of the monodentate coordination mode for the bond between the carboxylic group of the amino acid and the metal center. For complex nitrosyls, the identification of a characteristic band of NO in the form of NO+ is also noteworthy. The electron spectra of M(III) complexes presented bands associated with d-d and/or MLCT transitions and, for the Ru(II) complexes of LMCT. Electrochemical studies allowed evaluating the redox processes centered on the metallic center, with evidence of a coupled reaction with the formation of an aquacomplex, in addition to qualitatively investigating the release of methionine (or DMSO, for the complex with substituted cyclen), when submitted to electrochemical stimulation. Preliminary kinetic reactivity data confirm the aquation with release of chloride and DMSO in the complexes trans-[CoCl2(cyclam)]Cl and cis-[Ru(dmso)2(Et cyclen)]Cl, respectively, and confirm the entry of amino acid while the water molecule leaves the Co(III) coordination sphere. Interaction studies of chlorocomplexes with DNA were sufficient to suggest that these complexes interact with DNA. 1H NMR data, together with spectroscopic and electroanalytical analysis, confirm the proposed structures for the new complexes. Therefore, the results obtained support the formulation of the new synthesized complexes, as well as suggest the interaction of the respective chlorocomplexes with DNA.