Extraction of silver (I) by calixarene amine derivatives: The medium effect on the stoichiometry of the phase transfer extraction process

Coordination chemistry of calix[4]arene derivatives with lower rim functionalisation and their applications

“…They also determined that 1:1 metal:calix [4]arene complexes were formed. They had earlier looked at the interaction of silver perchlorate with a series of calix [4]arene derivatives containing pendant arms having a number of different functional groups [69]. Here they found that the solvent system played a role in the stoichiometry of the complex formed in the extraction process with a 1:1 complex (ligand:metal cation) being formed in the water-nitrobenzene process while a 1:2 complex (ligand:metal cation) being formed in the water-dichloromethane process.…”

Silver electrowinning from silver(I)–calixarene complexes by two-phase electrolysis

“…The ionic conductivity of the acid-free dichloromethane is 10 -5 S m -1 [11], whereas that of wetted dichloromethane is almost one order of magnitude greater and would have been increased further by dissolving the silver(I) complexed with calixarene [5]. To decrease ohmic potential losses, 0.01 mol dm -3 tetra-butyl-ammonium perchlorate (TBAP) was added as a supporting electrolyte.…”

“…3, it is also evident that the stoichiometry of silver(I) complexation with LBC and THIO differed. From the points of the linear parts intersection on the graphs (dashed lines) and their projection on the x-axis [5], the following reaction stoichiometry for silver(I) complexation by THIO was suggested:…”

“…Calixarenes and their derivatives have attracted considerable attention as novel extractants, able to recognize and discriminate metal ions, making them suitable as specific receptors [2][3][4]. In these studies, silver(I) has been investigated more frequently than the other metals [5][6][7], including palladium and platinum and heavy metals alone or in mixtures with different noble metals [5,7]. It was found that alkali and alkaline earth metals would be coextracted readily with most calixarenes [2,4,[7][8][9][10].…”

Solvent extraction of silver from nitric acid solutions by calix[4]arene amide derivatives

“…Their ability to recognize and discriminate different ions or molecules is one of their most remarkable features making them suitable as specific receptors [1][2][3]. To date, numerous attractive calixarene derivatives, possessing on their lower rim ester-, ketone-, amine-, amide-, alkyl-, sulfonyl-or other functional groups, have been synthesized and investigated as novel cyclic extractants for metal ions [2][3][4][5][6][7][8][9][10][11][12]. The abilities of these derivatives to transfer various metals from an aqueous into an organic phase have been widely studied during the past two decades, but the published papers had a rather fundamental than a practical character.…”