2022-05-192022-05-192010Talanova, G. G., Talanov, V. S., Surowiec, K., & Bartsch, R. A. (2010). Effect of Na⁺ on solvent extraction of alkaline earth metal cations by proton-ionizable calix[4]arenes. ARKIVOC, 2010(7), 160-169. https://doi.org/10.3998/ark.5550190.0011.712https://doi.org/10.3998/ark.5550190.0011.712https://hdl.handle.net/2346/89329This work is licensed under a Creative Commons Attribution 4.0 International License.Metal ion recognition by proton-ionizable calixarenes is often affected by interference from the Na+ present in many aqueous solutions. To assess the Na+ -effect on calixarene selectivity towards alkaline earth metal cations (AEMC), competitive solvent extraction of Mg2+, Ca2+, Sr2+ , and Ba2+ from aqueous solutions into chloroform by di-ionizable calix[4]arene N- (trifluoromethylsulfonyl)carboxamides and corresponding carboxylic acids, conformationally mobile and restricted to cone, partial cone and 1,3-alternate conformations, was investigated in the absence and in the presence of aqueous-phase Na+ . The extraction selectivities were found to be altered due to contrasting Na+ -induced changes in the AEMC uptake. Observed increases in loadings of smaller AEMC are rationalized by their co-extraction with Na+.engNa+-EffectSelectivityAlkaline Earth Metal CationsCalix[4]arenesSolvent ExtractionArticle