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  • 1
    Electronic Resource
    Electronic Resource
    CORRELATION OF COMPLEXATION RATE CONSTANTS OF 1:1 IRON CHELATES WITH LIGAND DISSOCIATION CONSTANTS. FOOD CONSIDERATIONS (2003)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food biochemistry 27 (2003), S. 0 
    Details
    ISSN: 1745-4514
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Iron which is present as a trace species in foods and drinks is very important to the young infant for normal growth and development. Nutritional status of iron may affect the metabolism of other nutrien***ts. Iron chelates have been shown to have a significant beneficial effect on metal status by increasing metal bioavailability in human diets.From a study of the complexation of iron(III) with a series of structurally similar dicarbonylic ligands in aqueous solution, thermodynamic and kinetic parameters have been obtained. The existence of an essential reaction mechanism throughout the series has been proved. The established correlation suggests that complexation rates of a structurally similar 1:1 chelate of iron(III) may be predicted from the ligand dissociation constant. Thus, an achievable objective might be to develop quantitative scales of ligand ionization degree for predicting expected behavior of complexation reactions. Since the differences observed in the rates of complex formation are not a result of steric effects but of changes in the metal-ligand electron density, a free-energy relationship has been obtained for the complexation reactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1745-4514.2003.tb00286.x
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  • 2
    Electronic Resource
    Electronic Resource
    Analytical relationships between the ionization of 1,3-dicarbonylic ligands and stability of their Cr(III), Ni(II), Co(II) and Cu(II) 1∶1 chelates (1992)
    Springer
    Journal of solution chemistry 21 (1992), S. 1145-1152 
    Details
    ISSN: 1572-8927
    Keywords: Chromium(III) ; β-diketones ; β-diketonates ; chelation ; complexation ; correlation ; stability ; equilibrium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract It has been demonstrated that the logarithm of the stability constant of some monochelated chromium(III) compounds, with structurally similar 1,3-dicarbonylic species, is linearly related to the negative logarithm of the acid ionization constant of the ligand. Graphical and analytical correlations which could be useful in predicting equilibrium constants of chromium(III)-β-diketonates, as well as other first-row transition metal derivatives, have been developed. A quantitative evaluation of the complexes stability has been carried out, providing information about the effects of ligand substituents on the equilibrium constants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00651860
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  • 3
    Electronic Resource
    Electronic Resource
    Mono-complex formation kinetics of 2-acetylcyclohexanonatochromium(III) in aqueous solution (1992)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 24 (1992), S. 533-540 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics and mechanism of the reaction of complexation of chromium(III) with 2-acetyl-cyclohexanone has been investigated spectrophotometrically in aqueous solution at 50°C and ionic strength 0.5 mol dm-3 NaClO4. The equilibrium constants of the complex have been determined. The mechanism proposed to account for the kinetic data involves a double reversible pathway where both Cr3+ and Cr(OH)2+ react with the enol tautomer of the ligand with rate constants of 9.6 × 10-3 dm3 mol-1 s-1, and 3.69 × 10-2 dm3 mol-1 s-1, respectively. Some discussions are made on the basis of Eigen-Wilkins theory considering the effect of solvent exchange on the complex formation.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550240603
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  • 4
    Electronic Resource
    Electronic Resource
    A novel correlative relationship among rates of complexation of 1:1 copper(II) diketonates and basicity of the ligand (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 26 (1994), S. 743-747 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An exceptional kinetic behavior on the reactivity of β-diketones against copper(II) have been found. Some relationship between ligand basicity and unexpected enhancement on the rates of complex formation, which may be useful for predicting rate constants of similar monochelated copper(II) complexes, are established. © 1994 John Wiley & Sons, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550260708
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  • 5
    Electronic Resource
    Electronic Resource
    Mono-complex formation kinetics of iron(III) with nonsubstituted octane and nonane 2,4-dicarbonyl ligands in aqueous solution (1993)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 25 (1993), S. 1005-1013 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics and mechanism of the reaction of complexation of iron(III) with 2,4-octanedione and 2,4-nonanedione have been investigated spectrophotometrically in aqueous solution at 10°C and ionic strength 0.5 mol dm-3 NaClO4. The equilibrium constants of the mono-complexes have been determined. The mechanism proposed to account for the kinetic data involves a double reversible pathway where both Fe3+ and Fe(OH)2+ react with the enol tautomer of the ligand. 2,4-Octanedione reacts with Fe3+ and Fe(OH)2+ with rate constants of 0.65 dm3 mol-1 s-1, and 14.07 dm3 mol-1 s-1, respectively. For 2,4-nonanedione complexation the rate constants determined are 0.49 dm3 mol-1 s-1, and 11.39 dm3 mol-1 s-1, respectively. Some discussions are made on the basis of Eigen-Wilkins theory considering the effect of solvent exchange on the complex formation. © 1993 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550251204
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  • 6
    Electronic Resource
    Electronic Resource
    Thermodynamic analysis of 1,3-dicarbonylic monochelates of iron(III) from equilibrium and kinetic measurements (1998)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 30 (1998), S. 121-127 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: From a study of the complexation of FeIII with 2,6-dimethyl-3,5-heptanedione in aqueous solution, thermodynamic and kinetic parameters have been obtained. Results obtained for this system and a series of structurally similar iron(III) diketonates at different temperatures, establishes isokinetic behaviors of these kinds of reactions.Analytical correlations obtained may be useful to predict, for analogous ligands in similar experimental conditions, an essential mechanism, that pathways involving reaction of metal-hydrolyzed species with the enol tautomer are faster than pathways involving hexa-aqua species. Additionally, thermodynamic parameters associated with the monochelated complexations may be predicted. © 1998 John Wiley & Sons, Inc. Int J Chem Kinet 30: 121-127, 1998.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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