64939-03-3Relevant academic research and scientific papers
Nitric oxide and nitroxyl formation in the reduction of trans-tetraamminenitrosyltriethylphosphiteruthenium(II) ion
Metzker, Gustavo,Stefaneli, Eliane Vasconcelos,Pereira, José Clayston Melo,Lima, Francisco Das Chagas Alves,Silva, Sebasti?o Claudino Da,Franco, Douglas Wagner
, p. 765 - 769 (2013)
The reduction of trans-[Ru(NO)(NH3)4(P(OEt) 3)]3+ ion was investigated in aqueous medium. Due to the phosphite ligand trans-effect and trans-influence, this complex selectively releases NO or HNO after one or tw
Nitric oxide and nitroxyl products from the reaction of L -cysteine with trans-[RuNO(NH3)4P(OEt)3](PF6)3
Pereira, José Clayston Melo,Souza, Maykon Lima,Franco, Douglas Wagner
, p. 1005 - 1011 (2015/03/04)
The reaction between the trans-[RuNO(NH3)4P(OEt)3](PF6)3 and L-cysteine (RS-) was studied over a pH range of 2.0-7.4. In this reaction, the concentrations of NO and HNO produced varied as a function of the pH of the solution. The first step of this reaction proceeded quickly [k1 = (3.5 ± 0.3) × 103 M-1 s-1, pH = 3.5, 25 C] and resulted in the formation of trans-[Ru(NH3)4P(OEt)3N(O)SR]2+, which dissociated to yield trans-[Ru(NH3)4P(OEt)3NO·]2+ and RS·. However, trans-[Ru(NH3)4P(OEt)3N(O)SR]n-1 can react with a second L-cysteine, yielding trans-[Ru(NH3)4P(OEt)3N(O)(SR)2]+ [k2 = (3.6 ± 0.1) M-1 s-1, pH = 3.5, 25 C]. Therefore, the trans-[Ru(NH3)4P(OEt)3NO·]2+ species released NO and the trans-[Ru(NH3)4P(OEt)3N(O)(SR)2]n-2 species released HNO.
Reactivity of Radicals Generated on Irradiation of trans-[Ru(NH 3)4(NO2)P(OEt)3](PF6)
Carlos, Rose Maria,Rodrigues Cardoso, Daniel,Castellano, Eduardo Ernesto,Osti, Renata Zachi,Camargo, Ademir Joao,Macedo, Luis Guilherme,Franco, Douglas Wagner
, p. 2546 - 2555 (2007/10/03)
The electronic absorption spectrum of trans-[Ru(NH3) 4(NO2)(P(OEt)3]+ in aqueous solution is characterized by a strong absorption band at 334 nm (λ max = 1800 mol-1 L cm-1). On the basis of quantum mechanics calculations, this band has been assigned to a MLCT transition from the metal to the nitro ligand. Molecular orbital calculations also predict an LF transition at 406 nm, which is obscured by the intense MLCT transition. When trans-[Ru(NH3)4(NO 2)(P(OEt)3]+ in acetonitrile is irradiated with a 355 nm pulsed laser light, the absorption features are gradually shifted to represent those of the solventocomplex trans-[Ru(NH3) 4(solv)(P(OEt)3]2+ (λmax = 316 nm, ε = 650 mol-1 L cm-1), which was also detected by 31P NMR spectroscopy. The net photoreaction under these conditions is a photoaquation of trans-[Ru(NH3)4-(NO 2)(P(OEt)3]+, although, after photolysis, the presence of the nitric oxide was detected by differential pulse polarography. In phosphate buffer pH 9.0, after 15 min of photolysis, a thermal reaction resulted in the formation of a hydroxyl radical and a small amount of a paramagnetic species as detected by EPR spectroscopy. In the presence of trans-[Ru(NH3)4(solv)P(OEt)3]2+, the hydroxyl radical initiated a chain reaction. On the basis of spectroscopic and electrochemical data, the role of the radicals produced is analyzed and a reaction sequence consistent with the experimental results is proposed. The 355 nm laser photolysis of trans-[Ru(NH3)4(NO 2)(P(OEt)3]+ in phosphate buffer pH 7.4 also gives nitric oxide, which is readily trapped by ferrihemeproteins (myoglobin, hemoglobin, and cytochrome C), giving rise to the formation of their nitrosylhemeproteins(II), (NO)Fe(II)hem.
Ruthenium tetraammines as a model of nitric oxide donor compounds
Toledo, Jose Carlos,Silva, Hildo A. S.,Scarpellini, Marciela,Mori, Vania,Camargo, Ademir J.,Bertotti, Mauro,Franco, Douglas W.
, p. 1879 - 1885 (2007/10/03)
The nitric oxide liberation from trans-[Ru(NH3) 4(L)(NO)]3+ (where L = py, 4-pic, isn, nic, L-His, 4-Clpy, imN) after one-electron-chemical or electrochemical reduction was investigated through spectroscopic and electrochemical techniques, reaction-product analysis and quantum-mechanic calculations. These complexes can be formally viewed as a RuII(NO+) species and the reduction site is located on the NO ligand. The E° for the trans-[RuII(NH3) 4(L)(NO+)]3+/trans-[RuII(NH 3)4(L)(NO)]2+ redox process ranges from 0.072 V vs. NHE (nic) to -0.118 V vs. NHE (imN). The specific rate constants for NO dissociation from trans-[RuII(NH3)4(L)(NO)] 2+, evaluated through double-step chronoamperometry, range from 0.025 s-1 (nic) to 0.160 s-1 (ImN) at 25 °C. The [Ru IINO+/ RuIINO°] redox potential and the specific rate constant (k-NO), key steps for designing nitrosyl complexes as NO-donor drug prototypes, proved to be controlled by a judicious choice of the ligand (L) trans to NO. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
