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Scientific paper - Original scientific paper
Kinetics and mechanism of oxidation of hydroxyurea derivatives with hexacyanoferrate(III) in aqueous solution
Croatica Chemica Acta, 84 (2011), 2; 133-147. https://doi.org/10.5562/cca1799
Budimir, Ana; Weitner, Tin; Kos, Ivan; Šakić, Davor; Gabričević, Mario; Bešić, Erim; Biruš, Mladen

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Budimir, A., Weitner, T., Kos, I., Šakić, D., Gabričević, M., Bešić, E. & Biruš, M. (2011). Kinetics and mechanism of oxidation of hydroxyurea derivatives with hexacyanoferrate(III) in aqueous solution. Croatica Chemica Acta, 84. (2), 133-147. doi: 10.5562/cca1799

Budimir, Ana, et al. "Kinetics and mechanism of oxidation of hydroxyurea derivatives with hexacyanoferrate(III) in aqueous solution." Croatica Chemica Acta, vol. 84, no. 2, 2011, pp. 133-147. https://doi.org/10.5562/cca1799

Budimir, Ana, Tin Weitner, Ivan Kos, Davor Šakić, Mario Gabričević, Erim Bešić and Mladen Biruš. "Kinetics and mechanism of oxidation of hydroxyurea derivatives with hexacyanoferrate(III) in aqueous solution." Croatica Chemica Acta 84, no. 2 (2011): 133-147. https://doi.org/10.5562/cca1799

Budimir, A., et al. (2011) 'Kinetics and mechanism of oxidation of hydroxyurea derivatives with hexacyanoferrate(III) in aqueous solution', Croatica Chemica Acta, 84(2), pp. 133-147. doi: 10.5562/cca1799

Budimir A, Weitner T, Kos I, Šakić D, Gabričević M, Bešić E, and sur.. Kinetics and mechanism of oxidation of hydroxyurea derivatives with hexacyanoferrate(III) in aqueous solution. Croatica Chemica Acta [Internet]. 2011 [cited 2024 November 22];84(2):133-147. doi: 10.5562/cca1799

A. Budimir, et al., "Kinetics and mechanism of oxidation of hydroxyurea derivatives with hexacyanoferrate(III) in aqueous solution", Croatica Chemica Acta, vol. 84, no. 2, pp. 133-147, 2011. [Online]. Available at: https://urn.nsk.hr/urn:nbn:hr:163:596614. [Accessed: 22 November 2024]

Metadata
Title (english)Kinetics and mechanism of oxidation of hydroxyurea derivatives with hexacyanoferrate(III) in aqueous solution
AuthorAna Budimir
AuthorTin Weitner
AuthorIvan Kos
AuthorDavor Šakić
AuthorMario Gabričević
AuthorErim Bešić
AuthorMladen Biruš
Author's institutionUniversity of Zagreb
Faculty of Pharmacy and Biochemistry
(Department of biophysics)
Author's institutionUniversity of Zagreb
Faculty of Pharmacy and Biochemistry
(Department of general and inorganic chemistry)
Scientific / art field,
discipline and subdiscipline		NATURAL SCIENCES
Chemistry
Inorganic Chemistry
Abstract (english)
Kinetics and mechanisms of the oxidation of methoxyurea and N-methylhydroxyurea were studied in neutral and basic aqueous solutions. The obtained pH dependences of the oxidation rates indicate that for both hydroxyureas the reactive species are the deprotonated ones. The second order rate constants, the activation enthalpies and the activation entropies for the reactions of methoxyurea (O-methylhydroxyurea) and N-methylhydroxyurea anions with Fe(CN)6 3− at 25 oC, I = 2 mol dm−3 (NaClO4) were determined as (5.06 ± 0.01) x 102 mol−1 dm3 s−1, (1.92 ± 0.02) x 104 mol−1 dm3 s−1, 27 ± 1 kJ mol−1, 16 ± 1 kJ mol−1, −101 ± 2 J mol−1 K−1, and −107 ± 4 J mol−1 K−1, respectively. The pKa value of methoxyurea at 25 oC and 2 mol dm−3 ionic strength was determined kinetically as 12.7 ± 0.1 and the thermodynamic parameters for the deprotonation reaction were determined as ΔaH = 43 ± 1 kJ mol−1, and ΔaS = −96 ± 4 J mol−1 K−1. When the kinetic results are compared with the data reported for hydroxyurea, an inverse dependence of the rate constants on the pKa of the hydroxyurea derivatives at 25 oC is observed. Such unexpected behaviour has been explained by the ab initio calculations and NBO analysis of HOMOs for all three hydroxyureates. (doi: 10.5562/cca1799)
Keywords (english)
Languageenglish
Publication typeScientific paper - Original scientific paper
Publication statusPublished
Peer reviewPeer review - international
Publication versionPublished version
Journal titleCroatica Chemica Acta
Numberingvol. 84, no. 2, pp. 133-147
p-ISSN0011-1643
e-ISSN1334-417X
DOIhttps://doi.org/10.5562/cca1799
URN:NBNurn:nbn:hr:163:596614
Publication2011
Document URLhttps://hrcak.srce.hr/71976
Type of resourceText
Access conditionsOpen access
Terms of useLicence In copyright icon
Created on2020-04-17 16:31:40