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Complexation of Lanthanide(III) Ions with Polyhydroxy Carboxylic Acids in Aqueous Solutions
Author(s) -
Giroux Sébastien,
Aury Sabrina,
Henry Bernard,
Rubini Patrice
Publication year - 2002
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/1099-0682(200205)2002:5<1162::aid-ejic1162>3.0.co;2-o
Subject(s) - chemistry , lanthanide , aqueous solution , ion , inorganic chemistry , carboxylic acid , organic chemistry
The complexation of lanthanum(III), europium(III), dysprosium(III), erbium(III), and lutetium(III) with D ‐gluconic acid (LH) was studied by pH potentiometry and NMR. The set of complexes formed in aqueous solutions and their stability constants β were determined, and the results were compared to those previously found for praseodymium(III) (S. Giroux et al., Polyhedron 2000 , 19 , 1567). A regular evolution of the β values was observed along the lanthanide series, particularly for the neutral complex MLH −2 (where two hydroxy functions were deprotonated) with a selectivity similar to that of EDTA. For the ML 2 + complex, where the ligand was coordinated via the carboxylate groups, the analysis of the 13 C NMR pseudo‐contact shift showed that the carboxylate group was not bidentate and that there was a participation of the α‐hydroxy group in the coordination. The study of the complexation of Pr III with other hydroxy carboxylic acids: glyceric, threonic, 2‐hydroxybutanoic, and 3‐hydroxybutanoic acids confirms that in the complex MLH −2 the deprotonated hydroxy groups, that intervene in the coordination with the metal ion, are those in α and γ positions relative to the carboxylate group. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)