Síntese, Caracterização, Reatividade e Aplicações Biológicas de Complexos de Ru(II) contendo tioamidas

Abstract

Four news coordinate compounds containing thiourea (Tu) and thiobenzamide (TBz) have interesting biological properties. The complexes nitrosyl, of the formulation cis-[Ru(NO)(L)(phen)2](PF6)3. H2O, where L = Tu ou TBz, have cytotoxic to human glioblastoma cells (GBM02 and U87), photoclivory action of plasmid pBR322 DNA, and ring dilation heme-dependent Wistar rat aort. Precursor complexes, of the formulation cis-[RuCl(L)(phen)2]PF6 H2O, such as nitrosyl with thiourea, also cleave DNA in the absence of light. In addition to that, the best photocleavage results are from nitrosyl complexes, but they do not dilate the aortic rings so well (between 30 and 40%). Compound formulation proposals were based on data computational correlations (DFT and TD-DFT) with spectroscopy in the infrared and ultraviolet-visible regions. Mass Spectrometry, Elemental Analysis, 1H NMR and 13C NMR endorsed the proposals made. In the cyclic voltammograms of the compounds there are waves corresponding to the reduction of the nitrosyl group – {RuNO6/7} – for the nitrosylocomplexes and oxidation of the metal center in the precursor complexes to distinct potentials of the cis-[Ru(phen)2Cl2]. This indicates the formation of chemically distinct complexes. Compounds containing the nitrosyl group release NO under visible light and exhibit 50% nitrosyl-nitro complex conversion at high pH relative to most analogous complexes; both properties are relevant for biological application. Furthermore, all complexes react against GSH and L-cysteine. This indicates that these thiols, present in the human body, react not only with the nitrosyl group, but also with the L fragment of the compounds. Based on this, the keywords of this work are: complexes, nitric oxide, thioamides, vasodilation and DNA cleavage.