title: Metal Recognition Driven by Weak Interactions: A Case Study in Solvent Extraction.
abstract: Tuning the affinity of a medium for a given metallic cation with the sole modification of weak interactions is a challenge for molecular recognition. Solvent extraction is a key technique employed in the recovery and purification of valuable metals, and it is facing an increased complexity of metal fluxes to deal with. The selectivity of such processes generally relies on the use of specific ligands, designed after their coordination chemistry. In the present study, we illustrate the possibility to employ the sole control of weak interactions to achieve the selective extraction of Pd(II) over Nd(III) : the control over selectivity is obtained by tuning the self-assembly of the organic phase. A model is proposed, after detailed experimental analysis of molecular (XRD, NMR) and supra-molecular (SAXS) features of the organic phases. We thus demonstrate that Pd(II) extraction is driven by metal coordination, whereas Nd(III) extraction requires aggregation of the extractant in addition to metal coordination. These results are of general interest for the applications which rely on the stabilization of metals in organic phases.
authors.affiliation: Laboratory of Hybrid Systems for the Separation (LHYS), Marcoule Institute for Separative Chemistry (ICSM), BP 17171, 30207, Bagnols-sur-Cèze, France.
authors.forename: Rémi
authors.initials: R
authors.lastname: Poirot
authors.affiliation: Laboratory of Matter in Environmental Conditions (L2 ME), Marcoule Institute for Separative Chemistry (ICSM), BP 17171, 30207, Bagnols-sur-Cèze, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Le Goff
authors.affiliation: Ions at Active Interfaces Laboratory (L2IA), Marcoule Institute for Separative Chemistry (ICSM), BP 17171, 30207, Bagnols-sur-Cèze, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Diat
authors.affiliation: Laboratory of Hybrid Systems for the Separation (LHYS), Marcoule Institute for Separative Chemistry (ICSM), BP 17171, 30207, Bagnols-sur-Cèze, France. damien.bourgeois@cea.fr.
authors.forename: Damien
authors.identifier: http://orcid.org/0000-0002-0762-3476
authors.initials: D
authors.lastname: Bourgeois
authors.affiliation: Laboratory of Hybrid Systems for the Separation (LHYS), Marcoule Institute for Separative Chemistry (ICSM), BP 17171, 30207, Bagnols-sur-Cèze, France.
authors.forename: Daniel
authors.initials: D
authors.lastname: Meyer
keywords: coordination chemistry; metal extraction; self-assembly; supramolecular chemistry; weak interactions