Investigation of the biological and photochemical properties of ruthenium mononuclear complexes with quinoline derivates and nitric oxide.

• Grant number: 23/15883-7
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: August 01, 2025
• End date: October 31, 2027
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Principal Investigator: Sofia Nikolaou
• Grantee: Hugo Elias Barbosa
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

This project proposes the synthesis, characterization, investigation of the acid-base reactivity and properties of biological interest of a series of novel ruthenium compounds with the general molecular formula [Ru(bpy)2L1L2]n+, with bpy= 2,2'-bipyridine, L1= isoquinoline derivatives, and L2=L1, NO+ and NO2-. The ligands and complexes will be synthesized in our laboratory in collaboration with Prof. Giuliano César Clososki, a professor at the Ribeirão Preto School of Pharmaceutical Sciences (FCFRP). Characterization will be carried out using elemental analysis experiments, cyclic voltammetry, differential pulse voltammetry, electronic absorption spectroscopy in the UV-Vis region, vibrational spectroscopy in the infrared region, luminescence spectroscopy and nuclear magnetic resonance spectroscopy, as well as mass spectrometry. The acid-base reactivity of the complexes will be investigated by spectrophotometrically monitoring the behavior of the complexes over the entire pH range in order to determine the pK of the NO+/NO2- coordinated interconversion reaction, thus identifying the species actually present in a physiological pH medium. The photoinduced release of nitric oxide from nitrosyl and nitro complexes will be investigated through photolysis experiments and determination of quantum yield by actnometry and also using nitric oxide selective electrodes. Due to the ability of the idealized compounds to be photosensitizers, singlet oxygen generation experiments will be carried out, in which this generation will be quantified. Experiments on the interaction of the complexes with fs-DNA (salmon sperm DNA) and HSA (human serum albumin) will be carried out through spectrophotometric titrations and application of the Stern-Volmer treatment, in order to study the potential of the complexes to interact with targets of biological interest, and circular dichroism experiments can also be used as a complement. Finally, the biological activity of the complexes will be determined by cytotoxicity tests against tumor cell lines. (AU)