A new calix[4]arene derivative and its ionic recognition for silver(i) and mercury(ii): the solvent effect

Abstract

A new lower rim partially functionalized calix [4]arene, namely, 5,11,17,23-tetra-tertbutyl[25,27-bis(diethylthiocarbamoyl)oxy]calix[4]arene, 1 was synthesized and characterized by 1 H NMR in different deuterated solvents to assess the degree of solvent-ligand interactions and the conformation of 1 in solution. 1 H NMR, conductometric and thermodynamic investigations reveal that this receptor interacts only with silver(I) and mercury(II) in dipolar aprotic media. The complexation process has been thermodynamically characterized and the results are compared with the corresponding data (when available) involving analogous ligands and these metal cations in the appropriate solvent. Emphasis is made on the difference between 'selective extraction' and 'selective ionic recognition' by receptors. Final conclusions are given.

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

“…As seen from online resource 3 and 4, in accordance with eqn (1). In order to take into account possible deviations from this well-known equation, we decided to extend it to a more general form, as…”

“…This large quantitative difference is obtained with an identical extraction mechanism, i.e. the involvement of four ligand units, three being deprotonated to ensure charge balance, eqn (1). For HL, the values of log K L are approximately 1.60, 1.70 and 2.0 logarithmic units lower than those obtained with 3-methyl-4-(4methylbenzoyl)-1-phenyl-pyrazol-5-one (HPMMBP, pK a = 4.02), 3-methyl-4-benzoyl-1-phenyl-pyrazol-5-one (HP, pK a = 3.92) and 3-methyl-1-phenyl-4-(4-trifluoromethylbenzoyl)-pyrazol-5-one (HPMFBP, pK a = 3.52) respectively.…”

“…However, in comparison to the huge amount of work performed aiming at enhancing extraction abilities through a careful design of various families of extracting agents, less attention has been paid to solvent formulation, mainly because the number of these is much more limited than the available library of extracting compounds. 1 Another very important milestone in the improvement of the extraction process was the discovery of the synergistic effect. 2 Synergism occurs when two ligands used in conjunction display better extraction efficiency than what could be expected from a simple addition of their individual effects.…”

Turning the volume down on heavy metals using tuned diatomite. A review of diatomite and modified diatomite for the extraction of heavy metals from water

“…Depending on the nature of the receptor, these are known Table 2 Summary of data on the removal of polluting ions from water by raw and modified diatomite. to complex and discriminate very effectively between anions or cations [93][94][95][96][97][98][99][100][101][102][103]. There is abundant evidence in the literature that these receptors can be tailored in order to interact with heavy metals without removing biologically essential ions.…”

Amphiphilic O-functionalized calix[4]resocinarenes with tunable structural behavior

“…Therefore, calixarene platform provides a wide potential for the controlled design of supramolecular architectures. It is noteworthy that the introduction of various substituents into the calixresorcinarene matrix may be used for modifying the efficiency and selectivity of binding of ions, 29 heavy metals, [30][31][32] organic molecules, [33][34][35] as well as increasing the antioxidant activity. 36 Besides, the nanostructures of various types (micelles, bers, vesicles, capsules) [37][38][39][40][41][42][43] can be created.…”