Complexation of alkali cations by calix[4]crown ionophores: Conformation and solvent dependent Na⁺/Cs⁺binding selectivity and extraction: MD simulations in the gas phase, in water and at the chloroform-water interface

High‐performance liquid chromatography with electrospray ionisation mass spectrometry and diode array detection in the identification and quantification of the degradation products of calix[4]arene crown‐6 under radiolysis

“…12 Hence, these compounds were extensively studied in several experimental 13 and molecular modelling investigations. 14,15 Extensive experiments in the nuclear industry with solvent systems indicate that the degradation of solvent due to exposure to radiolysis, and to a lesser extent hydrolysis, can significantly degrade its performance. Therefore, before developing an extraction process, 16 the radiolytic stability of the system and the characterisation of the degradation products must be investigated.…”

Rate of Interfacial Reactions Compared to Bulk Reactions in Liquid–Liquid and Micellar Processes: An Attempt to Clarify a Confusing Situation

“…Experimental studies, using newly developed techniques for the study of interfaces at the microscopic level (such as for instance total internal reflection spectroscopies (68)) are still needed in future to better understand the precise location and the mobility of extractants at the interface, as well as the influence of surfactants on these properties (69). At the same time, the efforts presently expended in the field of molecular dynamic simulations of interfacial reactions (37,(70)(71)(72) are probably only a preliminary step and their future development associated with the improvement of computer calculation times is extremely promising.…”

Development of highly selective compounds for solvent extraction processes: partitioning and transmutation of long-lived radionuclides from spent nuclear fuels

“…The selectivity of these ligands toward caesium is so high that they are better Cs + sensors than any other functionalized calix (Pérez-Jiménez et al, 1998). Molecular Dynamics calculations as well as X-ray crystallographic data suggest that, provided no steric hindrance is introduced in the polyether bridge(s), hydrophobic interactions exist between the extracted alkali cations and the π electrons of the aryl rings, hence favouring the binding of the less hydrated caesium cation as compared to harder alkali cations, such as sodium (Wipff and Lauterbach, 1995, Lauterbach and Wipff, 1996, Thuery et al, 1996, Lamare et al, 1997, 1998, Jankowski et al, 2003. As expected, although unusual in metallic complexation, the symmetrical arrangement of calix[4]arenes-biscrown-6 with two complexing cavities, is well adapted to the formation of both 1 : 1 (ligand : metal) and 1 : 2 complexes, as indicated by NMR, electro-spray ionization mass spectrometry (ESI-MS), and X-ray crystallographic studies (Arnaud-Neu et al, 1996, Allain et al, 2000.…”