Reactivity of trinuclear ruthenium acetates with nitrite and nitric oxide ligands in aqueous media

Autor(es)

Barbosa, Hugo E. ; da Silva, Amanda B. ; Nazar, Pedro H. O. ; Bertoloni, Renan R. ; de Oliveira-Filho, Antonio G. S. ; Nikolaou, Sofia

• Tipo de documento: Artigo Científico
• Fonte: DALTON TRANSACTIONS; v. 54, n. 23, p. 11-pg., 2025-05-20.

Resumo

The chemical reactivity of nitrosyl- and nitrite-coordinated compounds in an aqueous environment is a vital part of understanding the action of these compounds as potential nitric oxide-releasing molecules (NORMs). This work reports the behaviour of the [Ru3O(CH3COO)6(py)2NO2] (1) complex, which is an isomeric mixture of nitrite-N and nitrite-O, and the nitrosyl complex [Ru3O(CH3COO)6(py)2NO]PF6 (2) in aqueous medium with and without light irradiation. NO release under light irradiation was detected through chronoamperometry, which showed that nitrite complex 1 produces NO but is less effective than nitrosyl complex 2. This difference is due to the mechanism of NO production by complex 1, which depends on the nitrite-O isomer, present in minor proportion in the synthetic sample, as shown by computational and NMR data. The reactivity of these compounds in the dark was investigated under various pH values. The nitrite complex 1 had the coordinated nitrite converted to NO+, with a pK = 4.2. NO+ was readily released, yielding the solvate species [Ru3O(CH3COO)6(py)2S]+. For the nitrosyl complex 2, two successive nucleophilic attacks by hydroxide ions were observed producing the [Ru3O(CH3COO)6(py)2HNO2] (3) and [Ru3O(CH3COO)6(py)2NO2]- (4) compounds, with pK values of 9.8 and 12.3, respectively. In buffered solutions (TRIS.HCl and PBS), the kinetic trace for the conversion of 2 to 3 suggested an induction period followed by the complete conversion to [Ru3O(CH3COO)6(py)2HNO2] at pH values where the nitrosyl [Ru3O(CH3COO)6(py)2NO]+ should be the major species. Based on these observations, our data suggest a sequence of steps in which compound 3 accumulates and then, with the aid of the buffer components, increases the rate of its own formation. (AU)

• Processo FAPESP: 20/15607-1 - Síntese, caracterização e propriedades biológicas de um complexo mononuclear de rutênio fotossensibilizador com um ligante volumoso e um intercalador de DNA com liberação fotoinduzida de NO
• Beneficiário: Renan Ribeiro Bertoloni
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 24/04574-6 - Síntese, caracterização e estudo biológico de compostos mononucleares de rutênio ciclometalados: liberação de moléculas alvo
• Beneficiário: Pedro Henrique Oliveira Nazar
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 21/00675-4 - Arquitetura de materiais para armazenamento de energia eletroquímica e catálise
• Beneficiário: Roberto Manuel Torresi
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 23/10722-5 - Design computacional de catalisadores bioinspirados à base de metais de transição para geração de H2
• Beneficiário: Renan Ribeiro Bertoloni
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 22/03478-8 - Reatividade de compostos polinucleares de rutênio com potencial aplicação biológica
• Beneficiário: Sofia Nikolaou
• Modalidade de apoio: Auxílio à Pesquisa - Regular