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A more environmentally friendly solvent extraction process was formulated for uranium extraction using diluent-free extractants based on trialkylammonium compounds. The effect of ammonium cations and anions toward extraction efficiency, viscosity and phase separation was also evaluated. These systems were shown to be highly efficient and simple to implement as they rely on the same chemical components as those applied in the actual industrial process. It has also been demonstrated that using such alternatives allows not only to prevent third phase formation and subsequent extractant degradation, but also reduces the evaporation loss of solvent by a factor of 20. Among the systems investigated, the pure [TOAH] 2 [SO 4 ] was selected as the simplest and most efficient. A comparative Life Cycle Assessment (LCA) was also conducted between this system and the conventional solvent to compare more objectively their sustainability. Results based on four environmental indicators show that the new system is 18 times less impactful. Contrary to expectations, this study also showed that the pure (diluent-free) extractant system needs to be at least 2 times more efficient in terms of metal extraction to become significantly more sustainable. Other main effects contributing to the LCA are derived from: (i) the production of chemicals, which is much more harmful for extractants than for aliphatic diluents, (ii) the loss of Volatile Organic Compounds (VOC) to the environment, and (iii) to a lesser extent, the additional centrifugation step that may be required to separate more viscous systems. • Highly efficient diluent-free extraction process based on mixtures of alkylammonium for uranium extraction in sulphuric medium. • Significant improvement of extraction capacity, competitors separation and phase stability. • Drastic reduction of the volatile organic compounds loss by evaporation. • Quantification of the environmental impacts through comparative life-cycle assessment. • Sustainability depends mostly on chemicals synthesis and on the higher extraction performance of the diluent-free system. [ABSTRACT FROM AUTHOR]

The recovery of noble elements from secondary source, industrial effluent, which are classified as high concentrated noble elements solution are very essential. Liquid-solid extraction systems are an attractive process used for the separation and purification of noble elements. For this purpose, a solid-phase extraction system was investigated for the recovery of noble metals (Au(III), Pd(II), and Rh(III)). Chelating resins were synthesized by a polycondensation reaction between phenolic thiourea monomers and formaldehyde under alkaline conditions. The resulting polymers were characterized and evaluated for their chelating properties with regard to noble metal sorption. Also, the selectivity of sorption of noble elements was studied in the presence of competitive elements that can be present in effluent waste, such as Zn, Cu, Ni, Fe, and Al. Here, we present a promising materials based on formo-phenolic thiourea resins as a potential candidate for high-capacity (> 350 mg/g for Au; > 50 mg/g for Pd; > 30 mg/g for Rh) and high-selectivity solid-liquid sorption of noble elements, particularly for Au. • Phenolic polymers incorporating thiourea functional groups have been prepared. • The incorporation of the functional groups has been demonstrated by complementary analytical techniques. • The thiourea phenolic polymers are efficient for the preferential sorption of noble elements. [ABSTRACT FROM AUTHOR]

Invited for this month′s cover is the collaborating group of Dr Guilhem Arrachart and Dr Stéphane Pellet‐Rostaing at Institut de Chimie Séparative de Marcoule (ICSM). The cover picture shows a person going uranium fishing thanks to the use of bis‐catecholamide materials. These materials have shown interesting performance for the recovery of uranium in saline environments such as seawater. More information can be found in the Research Article by G. Arrachart, S. Pellet‐Rostaing, and co‐workers. [ABSTRACT FROM AUTHOR]

Various structurally related glycolamide compounds were synthesised and evaluated by solvent extraction experiments for the separation of rare earth elements (REEs) from aqueous acid solutions using dodecane as the diluent. We describe herein the full synthesis of a family of bifunctional ligands with a central oxygen and focus our investigation on the effects of structural modification on the extraction efficiencies. The combination of an amide, a P O donor site, and a central oxygen in such a glycolamide ligand showed interesting extraction properties for heavy rare earth elements from phosphoric acid solutions. Image 1 [ABSTRACT FROM AUTHOR]

In the frame of solvent extraction processes, rather quick and efficient extraction of NaCl and some other salts from water was realized by simultaneous coordination of both cations and anions in the organic phase. A calixarene type compound 1 was used for cation complexation, while functionalized benzyl alcohol 2 acted as anion binding agent in organic phase. Importance of both extractants for efficient extraction was shown. A possibility of separation of different cations and anions was further demonstrated. X-ray structural study proved that extraction always takes place on molecular level. The NMR and μ-Raman spectroscopy studies displayed the character of ion binding by extractants molecules. By carrying out several cycles and changing temperature, the process is efficient for extraction and separation of different ions, and has found already its pilot industrial application. [ABSTRACT FROM AUTHOR]

Germanium extraction has been studied using ion-exchange process thanks to polymeric resins. The ion-exchange resins have been prepared from catechol and with admixture with 8-hydroxyquinoline by alkaline polycondensation with formaldehyde. The polymeric resins were characterized and involved in sorption experiment. The selectivity sorption of germanium was studied in the presence of elements such as silicon, zinc or copper which are likely to be competitive cations in solutions from urban mines or mine deposits. Selective extraction and separation of germanium have been demonstrated. Changes in the selectivities properties of the resins have been observed through the incorporation of 8-hydroxyquinoline in the catechol matrix. [ABSTRACT FROM AUTHOR]

Substitution of extracting molecules with a long perfluoroalkyl chain was performed in order to modulate the weak intermolecular interactions and the supramolecular ordering of an organic system employed to recover metals of interest during liquid–liquid extraction processes. The fluorous compounds were compared to their hydrocarbon counterparts: both molecules present a hydrophilic moiety, responsible for metal chelation, and a hydrophobic chain, which enables solubility into organic media. But this chain is also oleophobic in the case of the fluorous compound. We observed that the oleophobic character the fluorous chain prevails over the tendency of hydrophilic moieties to self-assemble: in the organic phase, fluorous compounds lead to direct aggregates with a fluorous core, whereas hydrocarbon compounds lead to reverse aggregates with a hydrophilic core. This difference of supramolecular ordering of the extracting molecules has a great impact on the extraction process, and its selectivity: Pd was selectively extracted over Nd although the complexing head of the extracting molecules remains identical. This study reveals that perfluoroalkyl chains can also be successfully employed to tune the extraction properties of organic phases, even when based on classical organic oils. [ABSTRACT FROM AUTHOR]

Keywords: catecholamides; chelation; resins; sorbent polymers; uranium extraction EN catecholamides chelation resins sorbent polymers uranium extraction 1 1 1 05/30/23 20230501 NES 230501 B The cover picture shows a person "fishing" for uranium b . Catecholamides, chelation, resins, sorbent polymers, uranium extraction Uranium extraction from unconventional resources like in seawaters constitutes an important secondary source of uranium as well as a challenge considering the complexity of this media. [Extracted from the article]

The water-soluble ligand N , N , N′ , N′ -tetrakis[(6-carboxypyridin-2-yl)methyl]ethylenediamine (H 4 tpaen) and its derivatives were synthesized and evaluated for Am/Cm separation by solvent extraction. In this context, different ligands were studied for their possible use as selective back-extraction agents of actinides, especially americium, from an organic TPH phase. The solvent consisted of different extractants mixtures (DMDOHEMA/HDEHP or TODGA/TBP systems) and was preliminarily loaded with trivalent lanthanide and actinide cations. The aim of these new water-soluble agents was to strip americium or curium in an aqueous acidic phase in order to perform their mutual separation while maintaining other cations in the organic phase. A specific ligand bearing n -alkoxy groups connected to the pyridyl rings of H 4 tpaen showed water solubility slightly enhanced associated with efficient back-extraction properties with the possibility to perform simultaneously inter-group separation of Am (III) from Eu (III), and intra-group separation of Am(III) from Cm(III). [ABSTRACT FROM AUTHOR]

Recycling chemistry of metals and oxides relies on three steps: dissolution, separation and material reformation. We review in this work the colloidal approach of the transfer of ions between two complex fluids, i.e. the mechanism at the basis of the liquid-liquid extraction technology. This approach allows for rationalizing in a unified model transformation such as accidently splitting from two to three phases, or uncontrolled viscosity variations, as linked to the transformation in the phase diagram due to ion transfer. Moreover, differences in free energies associated to ion transfer between phases that are the origin of the selectivity need to be considered at the meso-scale beyond parameterization of an arbitrary number of competing 'complexes'. Entropy and electrostatics are taken into account in relation to solvent formulation. By analogy with electronics dealing about electrons transported in conductors and semi-conductors, this 'ienaic' approach deals with ions transported between nanostructures present in colloidal fluids under the influence of chemical potential gradients between nanostructures coexisting in colloidal fluids. We show in this review how this colloidal approach generalizes the multiple chemical equilibrium models used in supra-molecular chemistry. Statistical thermodynamics applied to self-assembled fluids requires only a few measurable parameters to predict liquid-liquid extraction isotherms and selectivity in multi-phase chemical systems containing at least one concentrated emulsified water in oil (w/o) or oil in water (o/w) microemulsion. [ABSTRACT FROM AUTHOR]

Abstract: Chronic kidney disease (CKD) is associated with numerous metabolic and endocrine disturbances, including abnormalities of calcium and phosphate metabolism and an inflammatory syndrome. The latter occurs early in the course of CKD and contributes to the development and progression of vascular calcification. A few therapeutic strategies are today contemplated to target vascular calcification in patients with CKD: vitamin K2, calcimimetics and phosphate binders. However, none has provided complete prevention of vascular calcification and there is an urgent need for alternate efficient treatments. Recent findings indicate that tissue-nonspecific alkaline phosphatase (TNAP) may represent a very promising drug target due to its participation in mineralization by vascular smooth muscle cells. We report the synthesis of four levamisole derivatives having better inhibition property on TNAP than levamisole. Their IC50, K i and water solubility have been determined. We found that the four inhibitors bind to TNAP in an uncompetitive manner and are selective to TNAP. Indeed, they do not inhibit intestinal and placental alkaline phosphatases. Survival MTT tests on human MG-63 and Saos-2 osteoblast-like cells have been performed in the presence of inhibitors. All the inhibitors are not toxic at concentrations that block TNAP activity. Moreover, they are able to significantly reduce mineralization in MG63 and Saos-2 osteoblast-like cells, indicating that they are promising molecules to prevent vascular calcification. [Copyright &y& Elsevier]

• The third phase quenching observed for longer or branched tertiary amines is associated to reduced attractive interactions. • Thermodynamic analysis shows that longer or branched alkyl chains induce increased aggregates curvature free energy. • Curvature energy becomes a predominant inhibitor of metal free energy of transfer. • Metal transfer is decreased because of high entropic contribution originated by the extractants branching and packing. We consider a structural and thermodynamic analysis of uranium solvent extraction by tertiary amines for which the alkyl chain configuration has been modified. The first part of this work revealed that tertiary amines with longer or branched alkyl chains allow tuning the phase stability and uranium extraction by modifying the volume of the polar species extracted in the organic phase. A complete fit of SANS data confirms in this second part that this phenomenon is related to the supramolecular self-assembly of the tertiary amines into smaller reverse micelle like aggregates for longer or branched alkyl chains. It moreover shows that these smaller aggregates quench third phase formation thanks to reduced attractive interactions between them. A thermodynamic analysis based on the "ienaic" approach further rationalizes this effect by showing that alkyl chains have a significant effect on the aggregate's curvature free energy. The latter becomes a predominant inhibitor of uranium free energy of transfer due to the high entropic contribution originated by the extractants branching and packing. [ABSTRACT FROM AUTHOR]

• Phase stability of extraction systems used for uranium production can be controlled by the amine alkyl chains configurations. • Tertiary amines with longer or slightly branched alkyl chains maintain efficient extraction with better phase stability. • Phase stability is shown to be associated to reverse aggregates having smaller polar cores and less co-extracted water. • Bulkier branching of the alkyl chains hinders the formation of supramolecular reverse aggregates and any efficient extraction. Amine-based extraction processes are broadly exploited for the selective extraction of uranium from sulfuric leaching liquors. The molecular forces (that is, the enthalpy associated with the multi-scale structuration of tertiary amines) are balanced by entropic effects that have not yet been identified. This first part in a series of reports describes the effects of the alkyl chain configuration on the phase stability and aggregation properties of tertiary amines. It is demonstrated that tertiary amines with longer or slightly branched alkyl chains provide better phase stability and enable constant extraction of uranium. In comparison, more branching of the alkyl chains hinders the formation of a highly curved interfacial layer, thus preventing efficient extraction. Combined small-angle scattering determination of the nanostructures in the organic phase and oil–water surface tension measurements revealed that the alkyl chains effects on the efficiency of the extraction process and phase stability are associated with reverse aggregates with smaller polar core volumes and less co-extracted water, suggesting that packing of the alkyl chains has a direct impact on the extraction efficiency of the solvent extraction system. [ABSTRACT FROM AUTHOR]

Abstract: Synthesis of modified EDTA and DTPA ligands and determination of their binding affinities for the uranyl cation are described. Thanks to a screening method, based on a chromophoric complex displacement procedure, chelating properties were studied in aqueous media under various pH conditions for evaluation of their in vivo uranyl-removal efficacy. Each ligand showed a more or less pronounced affinity for uranium. Specific ligands based on EDTA or DTPA analogues containing sulfocatecholamide (CAMS) were found to exhibit a significant affinity towards uranyl ion in acidic, neutral or basic conditions. [Copyright &y& Elsevier]

Abstract: The electrodeposition of indium is reported in a new weakly hygroscopic piperidinium-based ionic liquid (1-butyl-1-ethyl-piperidinium bis(trifluoromethylsulfonyl)imide) that allows electrodeposition to be performed without a glove box. The electrochemistry of indium is thoroughly investigated and the drawbacks of using metal chloride precursors in Tf2N-based electrolytes are highlighted using cyclic voltammetry and stripping experiments. Voltammograms revealed complex electrochemical behaviour and several cathodic and anodic signals that could be attributed to the formation of indium chloro complexes during the scan, due to changes in the concentration ratio [Cl−]/[In(III)] of interfacial species during the In(III) reduction reaction. A procedure for the electrodeposition of indium avoiding the use of the indium chloride precursor is then proposed. It offers an improved morphology of the electrodeposit and an increase in faradic yield from 33% to 85% compared to chloride-containing RTILs. [Copyright &y& Elsevier]

Rare-earth elements (REEs) are involved in most high technology devices and have become critical for many countries. The progress of processes for the extraction and recovery of REEs is therefore essential. Liquid–solid extraction methods are an attractive alternative to the conventional solvent extraction process used for the separation and/or purification of REEs. For this purpose, a solid-phase extraction system was investigated for the extraction and valorization of REEs. Ion-exchange resins were synthesized involving the condensation of terephthalaldehyde with resorcinol under alkaline conditions. The terephthalaldehyde, which is a non-hazardous aromatic dialdehyde, was used as an alternative to formaldehyde that is toxic and traditionally involved to prepare phenolic ion-exchange resins. The resulting formaldehyde-free resole-type phenolic resins were characterized and their ion-exchange capacity was investigated in regard to the extraction of rare-earth elements. We herein present a promising formaldehyde and phenol-free as a potential candidate for solid–liquid extraction REE with a capacity higher than 50 mg/g and the possibility to back-extract the REEs by a striping step using a 2 M HNO3 solution. [ABSTRACT FROM AUTHOR]

• Evidencing of phase separation behaviors of using thermosensitive and flocculation properties. • Investigation of sorption properties in acidic Gd/Th/U solutions. • Highlighting the high selectivity for thorium and uranium. In this work, the investigation of thermosensitive behavior of P(CPAAm6C) highlighted the formation of particles with an average radius of about 1940 nm in nitric acid. While h P(CPAAm6C) does not exibit thermosensitive behavior, it was shown this polymer had floculation properties. The selective sorption properties of two valuable carbamoylmethylphosphonated-based polymers regarding to Th/U/Gd mixtures were studied. The influence of the total concentration of cations on the sorption of each cation was investigated. In the case of P(CPAAm6C), sorption experiments evidenced that the Q max (Th) should be higher than 1.5 mmol·g−1. Sorption results with h P(CPAAm6C) evidenced that Q max (U) should be higher than 2.75 mmol·g−1. Moreover, the results highlighted the different selectivities between the carbamoylmethylphosphonate and carbamoylmethylphosphonic diacid functions. The phase separation behavior and selectivity will be of great interest for the design of a future environmental-friendly process for hydrometallurgical treatments of rare earth ores. [ABSTRACT FROM AUTHOR]

In the context of the separation of uranium and plutonium from spent fuel allowed by N,N -dialkylamides, three regioisomers of N,N -di(2-ethylhexyl) butyramide (DEHBA or ββ) and the diastereopure isomers of N -(2-ethylhexyl)- N -(oct-3-yl)butyramide (EHOBA or αβ) were synthesized to assess their extraction performance and to study the mechanisms at the origin of the differences observed between the stereo- and regioisomers. The N,N -dialkylamides showed differences in extraction, with a greater effect of regio- than stereoisomerism. A mechanistic study at both the molecular and supramolecular scales was initially applied to explain these effects. X-ray absorption and UV-vis spectroscopy showed that uranium is extracted by a UO 2 (NO 3 ) 2 L 2 complex, which is not very sensitive to steric hindrance, while plutonium is extracted by two complexes, Pu(NO 3 ) 4 L 2 and Pu(NO 3 ) 6 (HL) 2 , which are differently affected by stereo- and regioisomerism. Investigations at the supramolecular scale also showed that Pu(NO 3 ) 4 L 2 complexes are disadvantaged by the bulkiness of the extractants, while Pu(NO 3 ) 6 (HL) 2 is favored by the preformation of larger supramolecular aggregates.

Silica-based porous liquids (PLs) are innovative and versatile liquid materials with a high potential, although their application is often restricted to gas sorption. In this work, we propose to evaluate their potential to extract metals. For this goal, we have adapted their synthesis to provide PLs functionalized with thiols that are expected to chelate metallic contaminants, such as lead. As the accessibility of liquids and metals to the PL's porous network is one of the key points for their application, we developed an original small-angle neutron scattering experiment to verify that the PL is permeable to polar liquids. Then, preliminary extraction tests have successfully been carried out, with an extraction of lead cations by complexation on one-third of accessible thiol groups. This work demonstrates that the extraction of metal species by a PL is possible and opens many perspectives for optimization.

Developing greener hydrometallurgical processes implies offering alternatives to conventional solvents used for liquid-liquid extraction (LLE) of metals. In this context, it is proposed to substitute the organic phase by a hydrophobic silica-based porous liquid (PL). Two different sulfonated hollow silica particles (HSPs) are modified with various polyethoxylated fatty amines (EthAs) forming a canopy that provides both the targeted hydrophobicity and liquefying properties. This study shows that these properties can be tuned by varying the number of ethylene oxide units in the EthA: middle-range molecular weight EthAs allow obtaining a liquid at room temperature, while too short or too long EthA leads to solid particles. Viscosity is also impacted by the density and size of the silica spheres: less viscous PLs are obtained with small low-density spheres, while for larger spheres (c.a. 200 nm) the density has a less significant impact on viscosity. According to this approach, hydrophobic PLs are successfully synthesized. When contacted with an aqueous phase, the most hydrophobic PLs obtained allow a subsequent phase separation. Preliminary extraction tests on three rare earth elements have further shown that functionalization of the PL is necessary to observe metal extraction., (© 2023 The Authors. Advanced Science published by Wiley-VCH GmbH.)

This study presents a comprehensive investigation of the aggregation behavior of a malonamide extractant molecule ( N , N '-dimethyl, N , N '-dioctylhexylethoxymalonamide (DMDOHEMA)) in three different solvents, including two piperidinium- and (trifluoromethylsulfonyl)imide-based ionic liquids (1-ethyl-1-butylpiperidinium bis(trifluoromethylsulfonyl)imide ([EBPip + ][NTf 2 - ]) and 1-ethyl-1-octylpiperidinium bis(trifluoromethylsulfonyl)imide ([EOPip + ][NTf 2 - ])) and n -dodecane. By combining polarizable molecular dynamics simulations and small-angle X-ray scattering experiments, we extensively investigated the arrangement of supramolecular assemblies of the extractant molecules. Our results showed that the insertion of the alkyl chains of the extractant molecules into the apolar domain of [EOPip + ][NTf 2 - ] has a significant impact on the aggregation behavior of the extractant molecules, leading to the formation of smaller aggregates having a higher dispersion compared to other solvents. These findings provide new insights into the physicochemical properties of this type of system and are crucial in designing more effective solvents for rare earth metal extraction.

Efficient and selective extractions of precious and critical metal ions such as Au(III) and Pd(II) were investigated using zirconia nanoparticles surface modified with different organic mono- and di-carbamoyl phosphonic acid ligands. The modification is made on the surface of commercial ZrO 2 that is dispersed in aqueous suspension and was achieved by optimizing the Bronsted acid-base reaction in ethanol/H 2 O solution (1:2), resulting in inorganic-organic systems of ZrO 2 -L n (L n : organic carbamoyl phosphonic acid ligand). The presence, binding, amount, and stability of the organic ligand on the surface of zirconia nanoparticles were confirmed by different characterizations such as TGA, BET, ATR-FTIR, and 31 P-NMR. Characterizations showed that all the prepared modified zirconia had a similar specific surface area (50 m 2 .g -1 ) and the same amount of ligand on the zirconia surface in a 1:50 molar ratio. ATR-FTIR and 31 P-NMR data were used to elucidate the most favorable binding mode. Batch adsorption results showed that (i) ZrO 2 surface modified with di-carbamoyl phosphonic acid ligands had the highest adsorption efficiency to extract metals than mono-carbamoyl ligands, and (ii) higher hydrophobicity of the ligand led to better adsorption efficiency. The surface-modified ZrO 2 with di-N,N-butyl carbamoyl pentyl phosphonic acid ligand (ZrO 2 -L 6 ) showed promising stability, efficiency, and reusability in industrial applications for selective gold recovery. In terms of thermodynamic and kinetic adsorption data, ZrO 2 -L 6 fits the Langmuir adsorption model and pseudo-second-order kinetic model for the adsorption of Au(III) with maximum experimental adsorption capacity q max = 6.4 mg.g -1 .

Surfactants aggregate in water into micelles, and these micelles incorporate organic substances to solubilize them. Hydrotropes are compounds that increase the solubility of hydrophobic substances in water without this form of aggregation. Decreasing the chain length of the classical surfactant Aerosol OT (AOT) from C8 to C5 results in a molecule with intermediate properties. Molecular dynamics simulations and surface tension measurements are performed on this short chain derivative of AOT. This compound shows high solubility and at the same time progressive weak aggregation. The hydration of head groups hinders significant plunging into a hydrophobic core, which leads to well defined liquid chain nanodomains. The transition to bicontinuous aggregates is in the concentration range of 1 mol L -1 . The sulfonate group of the head groups (placed at the water interface of worm-like aggregates) rather than the aggregate-aggregate interaction is responsible for the unusual small angle X-ray scattering pattern.

The nanoscale organization of some classes of ionic liquids is responsible for their singular properties. In this paper, we use polarizable molecular dynamics simulations and small-angle X-ray scattering to probe the structure of two piperidinium- and (trifluoromethylsulfonyl)imide-based ionic liquids ([EBPip + ][NTf 2 - ] and [EOPip + ][NTf 2 - ]) that differ in the alkyl chain length of their cation. The X-ray scattering intensities calculated numerically, from the radial distribution functions, are in excellent agreement with the experimental data. The analysis of the different contributions of the X-ray scattering data allowed us to highlight the correlations responsible for the low q peak observed for the long-chain alkyl cations. New angular analyses showed that anions were more likely to align with alkyl chains as their size increased, inducing angular correlation between anions at larger distances. They also showed that the long alkyl chains of the cations aligned more with each other than the short ones. These more aligned alkyl chains induce a smaller volume of the apolar microdomains compared to the well-studied imidazolium-based ionic liquids, leading to the smaller correlation distance for piperidinium-based ionic liquids.

Based on silica hollow nanospheres grafted with an ionic shell, silica-based type I porous liquids remain poorly exploited, despite their huge versatility. We propose here to explore the main synthesis step of these promising materials with a thorough characterization approach to evaluate their structural and porous properties. Modifying the main synthesis parameter, the mechanism of the spheres' formation is clarified and shows that the calcination temperature, the surfactant concentration as well as the micelle swelling agent concentration allow tuning not only the size of the nanospheres and internal cavities, but also the silica shell microporosity and, therefore, the accessibility of the internal cavities. This study highlights the key parameters of hollow silica nanospheres, which are at the basis of type I porous liquids synthesis with optimized structural and porous properties.

Separation processes based on room temperature ionic liquids (RTIL) and electrochemical refining are promising strategies for the recovery of lanthanides from primary ores and electronic waste. However, they require the speciation of dissolved elements to be known with accuracy. In the present study, Eu coordination and Eu III /Eu II electrochemical behavior as a function of water content in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIm][NTf 2 ]) was investigated using UV-visible spectrophotometry, time-resolved laser fluorescence spectroscopy, electrochemistry, and X-ray absorption spectroscopy. In situ measurements were performed in spectroelectrochemical cells. Under anhydrous conditions, Eu III and Eu II were complexed by NTf 2 , forming Eu-O and Eu-(N,O) bonds with the anion sulfoxide function and N atoms, respectively. This complexation resulted in a greater stability of Eu II , and in quasi-reversible oxidation-reduction with an E 0 ' potential of 0.18 V versus the ferrocenium/ferrocene (Fc + /Fc) couple. Upon increasing water content, progressive incorporation of water in the Eu III coordination sphere occurred. This led to reversible oxidation-reduction reactions, but also to a decrease in stability of the +II oxidation state (E 0 '=-0.45 V vs. Fc + /Fc in RTIL containing 1300 mm water)., (© 2020 Wiley-VCH GmbH.)

Soft matter structuring is a useful tool for the preparation of well-structured inorganic materials. Here, we report a strategy using a structured solvent based on binary mixtures as a directing agent for silica nanoparticles in aerogel elaboration. Binary mixtures involving water/ethanol and water/ tert-butanol have been respectively chosen as representatives of unstructured and structured solvents. The water/alcohol/TEOS systems were effectively characterized as surfactant-free microemulsions. The enhanced solvent structuring, however, disappears upon the reaction with TEOS, and assembly is directed by solvent structuring found in the binary mixtures. For the first time, the influence of solvent composition on the sol-gel reaction was investigated with respect to the reaction rate and the structuring behavior thanks to dynamic light scattering (DLS), small- and wide-angle X-ray scattering (SWAXS), and transmission electron microscopy (TEM) experiments. The silica nanoparticles aggregate in a different manner depending on the solvent composition, which allows the change in the morphology, the degree of interconnection, and the surface area of the resulting material. Silica nanoparticles with a very high surface area of up to 2000 m 2 /g can be obtained by this approach.