Determination of Successive Complexation Constants in an Ionic Liquid: Complexation of UO22+ with NO3− in C4-mimTf2N Studied by UV−Vis Spectroscopy

Sylvia Georg (1) , Isabelle Billard (1) , Ali Ouadi (1) , Laetitia Petitjean (2) , Michel Picquet (2) , Clotilde Gaillard (3) , Vitaly Solov’ev

1 IPHC - Institut Pluridisciplinaire Hubert Curien
2 ICMUB - Institut de Chimie Moléculaire de l'Université de Bourgogne [Dijon]
3 IPNL - Institut de Physique Nucléaire de Lyon

The complexation of UO22+ with NO3− has been investigated in the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide by UV−vis spectroscopy at T = 18.5 °C. The complexation is evidenced through the appearance of four peaks at 425, 438, 453, and 467 nm. EXAFS data indicate that the trinitrato complex, UO2(NO3)3−, is dominating the speciation for a reagent ratio of [NO3−]/[UO22+] > 3. Assuming three successive complexation steps, the conditional stability constants are calculated, the individual absorption spectra are derived, and a speciation plot is presented.

Mots clés: complexation, speciation, uranium, ionic liquid

Domaines: Radiochimie

Sylvia Georg, Isabelle Billard, Ali Ouadi, Laetitia Petitjean, Michel Picquet, et al.. Determination of Successive Complexation Constants in an Ionic Liquid: Complexation of UO22+ with NO3− in C4-mimTf2N Studied by UV−Vis Spectroscopy. Journal of Physical Chemistry B, 2010, 114 (12), pp.4276-4282. ⟨10.1021/jp9107624⟩. ⟨in2p3-00734038⟩