Reactivity of polynuclear ruthenium compounds with potential biological application

Abstract

In the context of the research carried out by my group, the LABiQSC2 (Laboratory of Biological Activity and Supramolecular Chemistry of Coordination Compounds, https://sites.usp.br/labiqsc2/), which focuses on investigation of the biological activity of ruthenium compounds as one of its main goals, this project aims to study the reactivity of some trinuclear complexes under conditions of biological interest or in order to obtain new complexes that are also potentially interesting for biological applications. Therefore, we will focus on water-soluble complexes with the general formula [Ru3O(CH3COO)6(L)3]CH3COO (L = H2O; 4-aminopyridine; imidazole; 1-(2-hydroxyethyl)imidazole; 1-(3-hydroxypropyl )imidazole; 1-(3-aminopropyl)imidazole; Imidazole-1-acetic acid), on the investigation of its acid-base chemistry and, specifically in the case of the complex [Ru3O(CH3COO)6(H2O)3]CH3COO , its reactivity with the amino acid histidine will be studied. The counterpoint to reactivity with amino acids will be done from the same type of study, but involving the labile complexes [Ru2O(CH3COO)2(py)4(L)2](PF6)2 (L = N-heterocyclic ligand). The reactivity of the [Ru3O(CH3COO)6(H2O)3]CH3COO complex will be further explored in order to establish a systematic synthetic method for binuclear complexes with the general formula [Ru2(¼-O){·2(N,N)-phen}2 {¼-·1(C),·2(N,N)-phen}2](PF6)2 through orthometalation reactions of the phenanthroline series 1,10-phenanthroline, 5-chloro-1,10-phenanthroline, 5- methyl-1,10-phenanthroline and 1,10-phenanthroline-5,6-dione. We will also study the release of biological actives molecules CO and NO from redox stimulation through the reactions of the complexes [Ru3O(CH3COO)6(pyridine)2(L)] (L = CO or NO) with the redox agents H2O2 and ascorbic acid. In all cases, the complexes will be synthesized and purified and their characterization will be carried out by spectroscopic (NMR, UV-visible, infra-red) and electrochemical (cyclic voltammetry) techniques, complemented by measurements of elemental analysis and mass spectrometry. EPR measurements at liquid helium temperature (< 10 K) and excited state dynamics will be performed at The Ohio State University, in collaboration with the Turro Research Group. The study of reactivity and identification of the species involved in the reactions will be carried out with monitoring by UV-visible spectroscopy or by cyclic voltammetry and by spectroelectrochemical measurements. (AU)