Mono-complex formation kinetics of iron(III) with nonsubstituted octane and nonane 2,4-dicarbonyl ligands in aqueous solution

✍ Scribed by Carlos A. Blanco; Jose M. Romero; Jesus Verdu

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 421 KB
• Volume: 25
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550251204

✦ Synopsis

The kinetics and mechanism of the reaction of complexation of iron(II1) 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 NaC104. The equilibrium constants of the monocomplexes 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 Fc?(OH)~+ with rate constants of 0.65 dm3 mol-l s-l, and 14.07 dm3 mol-' s-', respectively. For 2,l-nonanedione complexation the rate constants determined are 0.49 dm3 mol-' s-', and 11.39 dm3 mol-' s-', respectively. Some discussions are made on the basis of Eigen-Wilkins theory considering the effect of solvent exchange on the complex formation. 0