Zahl A, van Eldik R (2006)
Publication Type: Journal article, Original article
Publication year: 2006
Original Authors: Gabričević M., Bešić E., Biruš M., Zahl A., Eldik R.
Publisher: Elsevier
Book Volume: 100
Pages Range: 1606-1613
Journal Issue: 10
DOI: 10.1016/j.jinorgbio.2006.05.008
Hydroxyurea (HU) effectively reduces vanadium(V) into vanadium(IV) species (hereafter V and V species, respectively) in acidic aqueous solution via the formation of a transient complex followed by an electron transfer process that includes the formation and subsequent fading out of a free radical, U (U ≡ H N-C(=O)N(H)O ). The electron paramagnetic resonance (EPR) spectra of U in H O/D O solutions suggest that the unpaired electron is located predominantly on the hydroxamate hydroxyl-oxygen atom. Visible and V -EPR spectroscopic data reveal HU as a two-electron donor, whereas formation of U , which reduces a second V , indicates that electron transfer occurs in two successive one-electron steps. At the molarity ratio [V ]/[HU] = 2, the studied reaction can be formulated as: 2 V + HU → 2 V + 0.98 CO + 0.44 N O + 1.1 NH + 0.1 NH OH. Lack of evidence for the formation of NO is suggested to be a consequence of the slow oxidation of HNO due to the too low reduction potential of the V /V couple under the experimental conditions used. The nuclear magnetic resonance ( V-NMR) spectral data indicate protonation of (H O) V O , and the protonation equilibrium constant was determined to be K = 0.7 M . Spectrophotometric titration data for the V -HU system reveal formation of (H O) V O(OH)U and (H O) V OU . Their stability constants were calculated as K = 5 M and K = 22 M , where the subscript digits refer to (H O) V O , HU and H , respectively. © 2006 Elsevier Inc. All rights reserved.
APA:
Zahl, A., & van Eldik, R. (2006). Oxidation of hydroxyurea with oxovanadium(V) ions in acidic aqueous solution. Journal of Inorganic Biochemistry, 100(10), 1606-1613. https://doi.org/10.1016/j.jinorgbio.2006.05.008
MLA:
Zahl, Achim, and Rudi van Eldik. "Oxidation of hydroxyurea with oxovanadium(V) ions in acidic aqueous solution." Journal of Inorganic Biochemistry 100.10 (2006): 1606-1613.
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