Complexos de rutênio com óxido nítrico: estrutura eletrônica, solvatação e natureza da ligação Ru-NO

Abstract

Since the discovery of Nitric Oxide (NO) as an important signaling molecule in many physiological and pathological processes in the human body, the scientific interest around this molecule had a significantly growth. Although this interest had led to the development andsynthesis of several metallic complexes, in the search for drugs able to release/capture of NO, there is still little theoretical information on the nature of the metal-ligand interaction and the mechanism of bond formation/breaking along the ligand displacement reactions involving thismolecule, besides other factors that could facilitate the development of new drugs. In this work the Density Functional Theory (DFT) was applied to the study of the molecular and electronic structure, electronic spectra and solvation of the species involved along the ligand exchange reactions: [Ru(NH3)6]3+/2+ + NO [Ru(NH3)5(NO)] 3+/2+ + NH3. The minimum energy reaction paths for these reactions were also analyzed and the energies, charge and spin densities along the reaction paths were investigated. For the Ru(III) compounds, two possiblespin states are allowed for the products and there is a non-adiabatic surface crossing between these two potential energy surfaces. The nature and magnitude of the intermolecular interactions involving the complexes and the solvent were analyzed using the statisticalmechanical Monte Carlo method. The Time Dependent Density Functional Theory was employed to obtain the electronic spectra of the species and to analyze the solvent effects on the electronic transitions.