Effects of First-Coordination Sphere and Buffers on the Nitrosyl-Nitrite Conversion Rate in Ru(II) Complexes

Author(s)

Rios, Rafaella Rebecchi ; Sousa Rodrigues, Phamilla Gracielli ; Biazzotto, Juliana C. ; Galembeck, Sergio Emanuel ; da Silva, Roberto Santana

• Document type: Journal article
• Source: European Journal of Inorganic Chemistry; v. 2022, n. 30, p. 8-pg., 2022-08-25.

Abstract

Nitrogen oxide derivative ruthenium compounds can deliver nitric oxide (NO) by chemical, electrochemical, or photochemical processes. Among these compounds, nitrosyl ruthenium complexes have been one of the most studied species. The sigma- and pi-character of the co-ligand L in [RuL5(NO)](n+) exerts a unique and determining effect on the structure of the complex and the NO delivery mode. We have found inconsistencies in this assertion. How the buffer medium influences the hydrolysis rate constant of nitrosyl ruthenium complexes such as cis-[Ru(NO)(bpy)(2)L](3++)(L=4-pic; py; isn and 4-acpy) has been evaluated in biphthalate, phosphate, and imidazole buffer solutions. For the studied ruthenium complexes, hydrolysis depended on the pi-acceptor character of ligand "L", with k(obs) increasing in the following order: 4-pic (AU)

• FAPESP's process: 19/19448-8 - Effect of photobiomodulation as synergistic addendum on photocytotoxicity of ruthenium-phthalocyanine compounds as nitric oxide and singlet oxygen producers: in vitro biochemical evaluation in two- and three-dimensional (3D) tumor cell lines
• Grantee: Roberto Santana da Silva
• Support Opportunities: Regular Research Grants