Iron(III) complexation by hydroxyurea in acidie aqueous perchlorate solution

Scientific paper - Original scientific paper

• Author: A. Bedrica
• Author: M. Biruš
• Author: N. Kujundžić
• Author: M. Pribanić; MBZ: 38805
• Author's institution: University of Zagreb; Faculty of Pharmacy and Biochemistry; (Department of analytical chemistry)
• Author's institution: University of Zagreb; Faculty of Pharmacy and Biochemistry; (Department of general and inorganic chemistry)
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry

Abstract (english)

Equilibrium and kinetic studies were performed to investigate
the complexation of aqueous high spin iron(III) by hydroxyurea
H2NC(O)NH(OH) in acidie solutions at 25 <c and I = 2.0 mol dm?
(maintained by NaC104). Complexation has been interpreted in
terms of coordination of the N-O oxygen atom and the NH2
nitrogen atom of the ligand to the iron(III) ion with concomitant
loss of a proton yielding the complex of the molar ratio 1 :1. The
equilibrium quotient for the formation of mono(hydroxyureato)iron
(III) complex is found to be Kl = 1.4. The kinetic results suggest
a parallel path mechanism involving substitution on Fe(H20)63+
and Fe(H20l50H2+ by the hydroxyurea, HU:
Fe (HzO)63+ + HU ;;= Fe (HzO)4 U2++ H+
Fe (H20)s (OH)2++ HU;;=' Fe (HzO)4 U2'
The formation of the complex occurs by the rate constants
kl = 16.8 M-l S-I and k1' = 5450 M" S-I. The analogous rate eonstants
for the reverse hydrolysis reactions were obtained as k-l =
= 11.8 M-l S-I and k_1' = 6.3 S-I. The results are compared with
kinetic data previously reported for the different mono(hydroxamato)
iron(III) complexes.

• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Journal title: Croatica Chemica Acta
• Numbering: vol. 61, no. 1, pp. 21-31
• p-ISSN: 0011-1643
• e-ISSN: 1334-417X
• URN:NBN: urn:nbn:hr:163:866907
• Publication: 1988
• Document URL: https://hrcak.srce.hr/175867
• Type of resource: Text
• Access conditions: Open access
• Created on: 2020-04-30 11:10:43