Impact of the Long‐Range Electronic Effect of a Fluorous Ponytail on Metal Coordination during Solvent Extraction

Abstract

With the need for a precise description of the long-range electronic effects of a perfloroalkyl chain (F-ponytail) grafted onto metal chelators, we studied in detail the effect of a spacer inserted between the polar complexing head and the F-ponytail, in relation to the metal coordination ability of the resulting molecules. The prepared molecules were then applied for the extraction of various metals from an aqueous phase into an organic phase, and the optimum spacer length could be estimated to be between three and four methylene units, according to the extraction conditions. The study also revealed the difficulty of modeling and anticipating the tiny energy differences involved in the extraction process and the importance in peculiar cases to go beyond only these studied inductive effects to understand better the factors that govern the stabilization of a metallic cation in a complex fluorous phase.

Maximized Lanthanide Extraction Using Supercritical CO2 and Fluorinated Organophosphate Extractants

“…Besides, in classical solvent extraction, studies between malonamides and fluorinated malonamides demonstrated their analogous complexation of metals. 64 Shimizu et al 31 proposed a chemical coordination for lanthanide oxides using a TBP− HNO 3 −H 2 O system, in which three nitrate anions are used for charge neutralization but the number of TBP molecules used varies. In this study, we utilized a molar ratio of 3.5 for the La 3+ /TFP extraction.…”

Solvent extraction of palladium(II) using diamides: A performing molecular system established through a detailed study of extraction kinetics

“…During our previous work, the fundamental studies performed along with the process development studies revealed that the initial design of the chosen diamide, N,N'-dimethyl-N,N'dibutylteradecylmalonamide (DBMA, Figure 1), was not optimized for selective Pd(II) extraction. 26,[28][29][30] DBMA was selected as this molecule is the former lanthanide/actinide separation molecule, so that it was readily available from French CEA. However, its molecular design has been performed targeting high distribution ratios for lanthanides(III) cations, [31][32][33] and its ability to also extract palladium(II) was instead a side-effect.…”