Skip to Main content Skip to Navigation
Journal articles

Perrhenate Complexation by Uranyl in Traditional Solvents and in Ionic Liquids: A Joint Molecular Dynamics/Spectroscopic Study

Abstract : The complexation of perrhenate (ReO4-) anions by the uranyl (UO22+) cation has been investigated by joint molecular dynamics simulations and spectroscopic (UV-vis, TRLFS, and EXAFS) studies in aqueous solution, acetonitrile, and three ionic liquids (ILs), namely, [Bmi][Tf2N], [Me3BuN][Tf2N], and [Bu3MeN][Tf2N] that are based on the same Tf2N- anion (bis(trifluoromethylsulfonyl)imide) and either Bmi+ (1-butyl,3-methylimidazolium), Me3BuN+, or Bu3MeN+ cations. They show that ReO4- behaves as a weak ligand in aqueous solution and as a strong ligand in acetonitrile and in the ILs. According to MD simulations in aqueous solution, the UO2(ReO4)2 complex quickly dissociates to form UO2(H2O)52+, while in acetonitrile, a stable UO2(ReO4)53- species forms from dissociated ions. In the ILs, the UO2(ReO4)n2-n complexes (n = 1 to 5) remained stable along the dynamics, and to assess their relative stabilities, we computed the free energy profiles for stepwise ReO4- complexation to uranyl. In the two studied ILs, complexation is favored, leading to the UO2(ReO4)53- species in [Bmi][Tf2N] and to UO2(ReO4)42- in [Bu3MeN][Tf2N]. Furthermore, in both acetonitrile and [Bmi][Tf2N] solutions, MD and PMF simulations support the formation of dimeric uranyl complexes [UO2(ReO4)4]24- with two bridging ReO4- ligands. The simulation results are qualitatively consistent with spectroscopic observations in the different solvents, without firmly concluding, however, on the precise composition and structure of the complexes in the solutions.
Document type :
Journal articles
Complete list of metadata

http://hal.in2p3.fr/in2p3-00690834
Contributor : Dominique Girod <>
Submitted on : Tuesday, April 24, 2012 - 3:06:41 PM
Last modification on : Thursday, June 17, 2021 - 3:19:01 PM

Identifiers

Collections

Citation

A. Chaumont, O. Klimchuk, C. Gaillard, I. Billard, A. Ouadi, et al.. Perrhenate Complexation by Uranyl in Traditional Solvents and in Ionic Liquids: A Joint Molecular Dynamics/Spectroscopic Study. Journal of Physical Chemistry B, American Chemical Society, 2012, 116, pp.3205-3219. ⟨10.1021/jp209476h⟩. ⟨in2p3-00690834⟩

Share

Metrics

Record views

195