Bicyclic and Acyclic Diamides: Comparison of Their Aqueous Phase Binding Constants with Nd(III), Am(III), Pu(IV), Np(V), Pu(VI) and U(VI)

December 27, 2004

Journal Article

Bicyclic and Acyclic Diamides: Comparison of Their Aqueous Phase Binding Constants with Nd(III), Am(III), Pu(IV), Np(V), Pu(VI) and U(VI)

Abstract

This report describes affinity measurements for two, water-soluble, methyl-alkylated diamides incorporating the malonamide functionality, N,N,N’,N’ tetramethylmalonamide (TMMA) and a bicyclic diamide (1a), towards actinide metal cations (An) in acidic nitrate solutions. Ligand complexation to actinides possessing oxidation states ranging from +3 to +6 was monitored through optical absorbance spectroscopy, and formation constants were obtained from the refinement of the spectrophotometric titration data sets. Species analysis gives evidence for the formation of 1, 4, 1, and 2 spectrophotometrically observable complexes by TMMA to An(III, IV, V, and VI), respectively, while for 1a, the respective numbers are 3, 4, 2, and 2. Consistent with the preorganization of 1a towards actinide binding, a significant difference is found in the magnitudes of their respective formation constants at each complexation step. It has been found that the binding affinity for TMMA follows the well established order: An(V)

Revised: October 25, 2005 | Published: December 27, 2004

Citation

Sinkov S.I., B.M. Rapko, G.J. Lumetta, B.P. Hay, J.E. Hutchison, and B.W. Parks. 2004. Bicyclic and Acyclic Diamides: Comparison of Their Aqueous Phase Binding Constants with Nd(III), Am(III), Pu(IV), Np(V), Pu(VI) and U(VI). Inorganic Chemistry 43, no. 26:8404-8413. PNNL-SA-41622.