Resumo:
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unpublished complexes synthesized were: cis-[Ru(dmso)2(Et-cyclen)]Cl,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.