Thenoyltrifluoroacetone: Preferable Molecule for Solvent Extraction of Metals—Ancient Twists to New Approaches

A review of the investigations devoted to the solvent extraction processes of metal ions with a chelating ligand thenoyltrifluoroacetone (HTTA) is presented herein. It seems that this molecule has been preferred in the field for more than half a century, and that it is used very often as an extractant for almost all metals. The main objective of the present review is also to provide an overview of the synergistic solvent extraction of lanthanoids, particularly with the use of a β-diketone−neutral mixture. Based on the previous published results in the open literature, the extraction efficiency has been examined in detail and discussed further mainly in terms of the corresponding equilibrium constants among other outlined, so-important parameters. Major conclusions on the role of ligating groups of extractants towards the mechanism, an improved extraction enhancement, and selectivity are additionally provided. The fact that ionic liquids (ILs) appear to be replacing volatile diluents in the field of the liquid–liquid extraction of metals, again with the participation of this β-diketone, is not surprising. As is well known, a very efficient and simple way to determine the stoichiometry of the extracted species in the organic phase is by the simple use of the slope analysis method; however, it is sometimes difficult to perform, either because it somehow requests good solubility of the ligand or because obtained slopes are quite often far from integer values in ILs.

Cation and anion effect on the biodegradability and toxicity of imidazolium- and choline-based ionic liquids

This work studies the effect of the cation and anion on the biodegradability and inhibition of imidazolium- and choline-based ionic liquids (ILs) using activated sludge. Six commercial ILs, formed by combination of 1-Butyl-3-methylimidazolium (Bmim⁺) and N,N,N-trimethylethanolammonium (Choline⁺) cations and chloride (Cl^-), acetate (Ac^-) and bis(trifluoromethanesulfonyl)imide (NTf₂^-) anions were evaluated, all representative counter-ions with markedly different toxicity and biodegradability. Inherent and fast biodegradability tests were used to evaluate both the microorganism inhibition and the IL biodegradability. In addition, the ecotoxicological response (EC₅₀) of the ILs was studied using activated sludge and Vibrio fischeri (Microtox® test). Bmim⁺ and NTf₂^- can be considered as non-biodegradable, whereas aerobic microorganisms easily degraded Choline⁺ and Ac^-. The biodegradation pattern of each cation/anion is nearly unaffected by counter-ion nature. Moreover, concentrations of CholineNTf₂ higher than 50 mg/L caused a partial inhibition on microbial activity, in good concordance with its low EC₅₀ (54 mg/L) measured by respiration inhibition test, which alerts on the negative environmental impact of NTf₂-containing ILs on the performance of sewage treatment plants.

A thermochromic europium(iii) room temperature ionic liquid with thermally activated anion–cation interactions

An observable and reversible case of thermochromism due to an unusual interaction between the countercation and the ligand of an europium(iii) tetrakis-β-diketonate room temperature ionic liquid is reported.

Are fancy acidic or neutral ligands really needed for synergism in ionic liquids? A comparative study of lanthanoid extraction in CHCl3 and an ionic liquid

Five lanthanoid ions were extracted with 3-methyl-1-phenyl-4-(4-phenylbenzoyl)-pyrazol-5-one in combination with calix[4]arene as a synergistic agent using CHCl₃ or 1-butyl-3-methylimidazolium-bis(trifluoromethanesulfonyl)imide as solvent.

A comprehensive strategy to boost the quantum yield of luminescence of europium complexes

Lanthanide luminescence has many important applications in anion sensing, protein recognition, nanosized phosphorescent devices, optoelectronic devices, immunoassays, etc. Luminescent europium complexes, in particular, act as light conversion molecular devices by absorbing ultraviolet (UV) light and by emitting light in the red visible spectral region. The quantum yield of luminescence is defined as the ratio of the number of photons emitted over the number of UV photons absorbed. The higher the quantum yield of luminescence, the higher the sensitivity of the application. Here we advance a conjecture that allows the design of europium complexes with higher values of quantum yields by simply increasing the diversity of good ligands coordinated to the lanthanide ion. Indeed, for the studied cases, the percent boost obtained on the quantum yield proved to be strong: of up to 81%, accompanied by faster radiative rate constants, since the emission becomes less forbidden.

Synthesis and properties of l-valine based chiral long alkyl chain appended 1,2,3-triazolium ionic liquids

l-Valine based alkyl (hexyl, octyl, dodecyl, cetyl, octadecyl) chain-appended 1,2,3-triazolium ionic liquids with iodide/hexafluorophosphate anions are found to possess favourable properties.

Homogeneous liquid–liquid extraction of neodymium(iii) by choline hexafluoroacetylacetonate in the ionic liquid choline bis(trifluoromethylsulfonyl)imide

Choline hexafluoroacetylacetonate diluted in the ionic liquid choline bis(trifluoromethylsulphonyl)imide has been used as an extractant for the homogeneous liquid–liquid extraction of neodymium(iii) ions.