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The [Ru(Hedta)NO](0.1-) system: structure, chemical reactivity and biological assays.
- Source :
-
Journal of inorganic biochemistry [J Inorg Biochem] 2004 Nov; Vol. 98 (11), pp. 1921-32. - Publication Year :
- 2004
-
Abstract
- 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 electrochemical), with E(NO+/NO)=-0.31 V vs SCE (I=0.2 M, pH 1), yielding [Ru(II)(Hedta)NO](-), which aquates slowly: k(-NO)=2.1+/-0.4x10(-3) s(-1) (pH 1.0, I=0.2 M, CF(3)COOH/NaCF(3)COO, 25 degrees C). At pHs>12, the predominant species, [Ru(II)(edta)NO](-), reacts according to [Ru(II)(edta)NO](-)+2OH(-)-->[Ru(II)(edta)NO(2)](3-), with K(eq)=1.0+/-0.4 x 10(3) M(-2) (I=1.0 M, NaCl; T=25.0+/-0.1 degrees C). The rate-law is first order in each of the reactants for most reaction conditions, with k(OH(-))=4.35+/-0.02 M(-1)s(-1) (25.0 degrees C), assignable mechanistically to the elementary step comprising the attack of one OH(-) on [Ru(II)(edta)NO](-), with subsequent fast deprotonation of the [Ru(II)(edta)NO(2)H](2-) intermediate. The activation parameters were DeltaH(#)=60+/-1 kJ/mol, DeltaS(#)=-31+/-3 J/Kmol, consistent with a nucleophilic addition process between likely charged ions. In the toxicity up-and-down tests performed with Swiss mice, no death was observed in all the doses administered (3-9.08 x 10(-5) mol/kg). The biodistribution tests performed with Wistar male rats showed metal in the liver, kidney, urine and plasma. Eight hours after the injection no metal was detected in the samples. The vasodilator effect of [Ru(II)(edta)NO](-) was studied in aortic rings without endothelium, and was compared with sodium nitroprusside (SNP). The times of maximal effects of [Ru(II)(edta)NO](-) and SNP were 2 h and 12 min, respectively, suggesting that [Ru(II)(edta)NO](-) releases NO slowly to the medium in comparison with SNP.
- Subjects :
- Animals
Crystallography, X-Ray
Edetic Acid chemistry
Edetic Acid pharmacokinetics
Electrochemistry
Male
Mice
Models, Molecular
Molecular Conformation
Nitric Oxide chemistry
Nitric Oxide pharmacokinetics
Ruthenium pharmacokinetics
Tissue Distribution
Edetic Acid analogs & derivatives
Ruthenium chemistry
Subjects
Details
- Language :
- English
- ISSN :
- 0162-0134
- Volume :
- 98
- Issue :
- 11
- Database :
- MEDLINE
- Journal :
- Journal of inorganic biochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 15522418
- Full Text :
- https://doi.org/10.1016/j.jinorgbio.2004.08.020