Kinetic study of the reactions of Np(V) and U(VI) with oxydiacetic acid

Citation
Ji. Friese et al., Kinetic study of the reactions of Np(V) and U(VI) with oxydiacetic acid, RADIOCH ACT, 83(4), 1998, pp. 175-181
Citations number
16
Categorie Soggetti
Inorganic & Nuclear Chemistry
Journal title
RADIOCHIMICA ACTA
ISSN journal
00338230 → ACNP
Volume
83
Issue
4
Year of publication
1998
Pages
175 - 181
Database
ISI
SICI code
0033-8230(1998)83:4<175:KSOTRO>2.0.ZU;2-T
Abstract
The rate and mechanism of complexation reactions of neptunyl(V) and uranyl( VI) by oxydiacetic acid at pH 3 in 1.0 M NaClO4 solutions has been investig ated by stopped-flow spectrophotometry. This tridentate ligand is able to a ccommodate the structural requirements of the linear dioxoactinide cations, and is known to form moderately stable complexes with these metal ions. As was reported previously in a study of diphosphonate complexes of these met al ions, the rate of formation of the respective 1:1 complexes is faster fo r Np(V) than U(VI), despite a stronger thermodynamic driving force for the latter. This result further supports the proposition that the rate of solve nt and ligand rearrangement in the precursor complex is an important parame ter in determining the rate of actinyl complexation reactions. The applicab ility of Marcus reaction rate theory, as modified by Albery, to complexatio n reactions of this type is discussed.