José Antonio Olabe

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The catalytic disproportionation of NH(2)OH has been studied in anaerobic aqueous solution, pH 6-9.3, at 25.0 degrees C, with Na(3)[Fe(CN)(5)NH(3)].3H(2)O as a precursor of the catalyst, [Fe(II)(CN)(5)H(2)O](3)(-). The oxidation products are N(2), N(2)O, and NO(+) (bound in the nitroprusside ion, NP), and NH(3) is the reduction product. The yields of(More)
Sodium nitroprusside (SNP, Na(2)[Fe(CN)(5)(NO)].2H(2)O) is a widely used NO-donor hypotensive agent, containing the formally described nitrosonium (NO(+)) ligand, which may be redox-interconverted to the corresponding one-electron (NO) and two-electron (NO(-)/HNO) reduced bound species. Thus, the chemistry of the three nitrosyl ligands may be explored with(More)
The [Ru(II)(Hedta)NO(+)] complex is a diamagnetic species crystallizing in a distorted octahedral geometry, with the Ru-N(O) length 1.756(4) A and the RuNO angle 172.3(4) degrees . The complex contains one protonated carboxylate (pK(a)=2.7+/-0.1). The [Ru(II)(Hedta)NO(+)] complex undergoes a nitrosyl-centered one-electron reduction (chemical or(More)
The kinetics and mechanism of the thermal decomposition of the one-electron reduction product of [Fe(CN)(5)NO](2-) (nitroprusside ion, NP) have been studied by using UV-vis, IR, and EPR spectroscopy and mass-spectrometric and electrochemical techniques in the pH range of 4-10. The reduction product contains an equilibrium mixture of [Fe(CN)(4)NO](2-) and(More)
The new compound [Ru(bpy)(tpm)NO](ClO4)3 [tpm = tris(1-pyrazolyl)methane; bpy = 2,2'-bipyridine] has been prepared in a stepwise procedure that involves the conversion of [Ru(bpy)(tpm)Cl]+ into the aqua and nitro intermediates, followed by acidification. The diamagnetic complex crystallizes to exhibit distorted octahedral geometry around the metal, with the(More)
Nitrosodisulfide S2NO(-) is a controversial intermediate in the reactions of S-nitrosothiols with HS(-) that produce NO and HNO. QM-MM molecular dynamics simulations combined with TD-DFT analysis contribute to a clear identification of S2NO(-) in water, acetone and acetonitrile, accounting for the UV-Vis signatures and broadening the mechanistic picture of(More)
We present a kinetic study of OH(-) additions to several nitrosyl complexes containing mainly ruthenium and different coligands (polypyridines, amines, pyridines, cyanides). According to a first-order rate law in each reactant, we propose a fast ion pair formation equilibrium, followed by addition of OH(-) to the [MX(5)NO](n) moieties, with formation of the(More)
The nitroprusside ion [Fe(CN)(5)NO](2-) (NP) reacts with excess HS(-) in the pH range 8.5-12.5, in anaerobic medium ("Gmelin" reaction). The progress of the addition process of HS(-) into the bound NO(+) ligand was monitored by stopped-flow UV/Vis/EPR and FTIR spectroscopy, mass spectrometry, and chemical analysis. Theoretical calculations were employed for(More)
The new complex, K(3)[Os(CN)(5)NH(3)].2H(2)O, a convenient precursor for the pentacyano-L-osmate(II) series, was prepared and characterized by chemical analysis, cyclic voltammetry, and IR and UV-vis spectroscopies. By controlled aquation in weakly acidic medium, the [Os(CN)(5)H(2)O](3-) ion was generated. Weak absorptions in the UV region for L = H(2)O,(More)
The reactions of hydroxylamine (HA) with several water-soluble iron(III) porphyrinate compounds, namely iron(III) meso-tetrakis-(N-ethylpyridinium-2yl)-porphyrinate ([Fe(III)(TEPyP)](5+)), iron(III) meso-tetrakis-(4-sulphonatophenyl)-porphyrinate ([Fe(III)(TPPS)](3-)), and microperoxidase 11 ([Fe(III)(MP11)]) were studied for different [Fe(III)(Porph)]/[HA](More)