Complexation thermodynamics and the structure of the binary and the ternary complexes of Am3+, Cm3+ and Eu3+ with IDA and EDTA+IDA

摘要

The stability and the associated thermodynamic parameters of the binary and the ternary complexes of trivalent Am, Cm, and Eu with IDA and with EDTA + IDA, were determined by using a solvent extraction technique for aqueous solutions of I = 6.60 in (NaClO4) at temperatures of 0-60 degrees C. The endothermic enthalpy and the positive entropy reflect the significant effect of dehydration in the formation of these complexes at high ionic strength. TRLFS and NMR (H-1 and C-13) data helped to establish the structure of the ternary complexes in solution. In the ternary complex M(EDTA)(IDA)(3-), EDTA binds via four carboxylates and two nitrogens, and IDA via two carboxylates and one nitrogen to the central Eu3+. (C) 2006 Elsevier B.V. All rights reserved.