Study of the interaction with biomolecules and photochemical properties of ruthenium cyclometalated nitrosyl complexes

• Grant number: 25/04901-0
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: July 01, 2025
• End date: November 30, 2025
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Principal Investigator: Sofia Nikolaou
• Grantee: Pedro Henrique Oliveira Nazar
• Supervisor: Carlos Alberto Lourenco de Serpa Soares
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Institution abroad: Universidade de Coimbra (UC), Portugal
• Associated to the scholarship: 24/04574-6 - Synthesis, characterization and biological study of mononuclear cyclometallated ruthenium compounds: release of target molecules, BP.MS

Abstract

This project aims to study the interaction with HSA and the photochemical properties of cyclometalated ruthenium nitrosyl complexes with the general formula [Ru(tpy)(C^N)NO](PF6)2, where tpy = 2,2¿:6¿,2¿¿-terpyridine and C^N = benzo[h]quinoline (Hbhq) (1) or 2-phenylpyridine (Hppy) (2). The complexes were synthesized, purified and characterized by the BEPE candidate during the development of his project in Brazil. Cyclometalated ruthenium complexes with Hbhq class ligands have shown promise in the design of new drugs, with considerably small IC50 values against various types of tumors, due to the greater hydrophobicity of cyclometalated compounds. The interest in NO lies in its biological functions, such as blood pressure regulation, cytotoxic activity in tumor cells through apoptosis, neurotransmission, stimulation of the immune response and antioxidant action. The structural characterization and part of the spectroscopic characterization of these compounds was carried out within the project carried out in Brazil (UV-vis absorption and steady-state fluorescence). This BEPE project proposes to carry out characterization by time-resolved fluorescence and ultrafast and nanosecond transient absorption, as well as investigating the deactivation of the excited states of the complexes mentioned through photoacoustic effect studies, with a view to their potential applications in photothermal therapies. We also intend to study the interaction of 1 and 2 with human serum albumin (HSA) using 1H NMR techniques, calorimetry measurements and molecular docking, with a view to investigating the type and intensity of binding with this protein.