New water-soluble calix[4]arene-bis(benzocrown-6) for caesium–sodium separation by nanofiltration–complexation

Abstract

Calix-bis(benzocrown-6) 6 and 7 were converted into the water-soluble receptors 9, 10, 12 and 15 by introducing hydroxy, carboxy, sulfato or diethanolamino groups at the para position of the phenolic ring and/or on the benzo-ether moieties. The complexation properties of these ionophores were studied for all alkali cations in methanolic and aqueous media. Stability constants were calculated by UV-Vis spectroscopy. All ligands showed a more or less affinity for the larger cations, depending on the nature and the position of the substituents grafted on the benzo-ether chain only or both on the calixarene ring and the benzo-ether loop. For selective Cs þ /Na þ separation, the efficiency of the ligands was evaluated by means of a nanofiltration system. In comparison with the known tetrahydroxylated bis-crown-6 calix[4]arene 1, compounds 9, 12 and 15 represent the most selective ligands for the Cs þ cation in a moderate salted medium ([NaNO 3 ]¼85 g/L).

Solvent Extraction of Cesium with a New Compound Calix[4]arene-bis[(4-methyl-1,2-phenylene)-crown-6]

“…(4) The synthesis of bis[1,2-[2′(2″-hydroxyethoxy)ethoxy]]-4-methylbenzene di- p -toluenesulfonate was carried out by reacting bis[1,2-[2′(2″-hydr-oxyethoxy)ethoxy]]-4-methylbenzene with p -toluenesulfonyl chloride by the esterification reaction at low temperature . (5) CalixBisMePhC was synthesized through 1,3- alternate cyclization of THCalix[4]arene with bis[1,2-[2′(2″-hydroxyethoxy)ethoxy]]-4-methyl-benzene di- p -toluenesulfonate in acetonitrile . It was catalyzed by cesium carbonate under refluxing in nitrogen atmosphere for 17 days.…”

“…25 (5) CalixBisMePhC was synthesized through 1,3alternate cyclization of THCalix [4]arene with bis[1,2-[2′(2″hydroxyethoxy)ethoxy]]-4-methyl-benzene di-p-toluenesulfonate in acetonitrile. 26 It was catalyzed by cesium carbonate under refluxing in nitrogen atmosphere for 17 days. The resultant CalixBisMePhC shown in Figure 2 was then characterized by elementary analysis, 1 H NMR, and ESI-MS.…”

Water-Soluble Calix[4]arene Derivatives: Binding Stoichiometry and Spectroscopic Evaluation of the Host-Guest Recognition Mechanism

“…26 The water-soluble calix [4]arene-bisbenzocrown-6 (1) derivatives are also reported to separate the caesium-sodium by nanofiltration-complexation. 27 The voltammetric study on a water-soluble calix [4]arene (calix [4]arene-triacid-monoquinone (2), CTA, and calix [4]arene-triacid-diquinone (3)), which bind with the Ca 2+ , Sr 2+ , Ba 2+ in basic aqueous solution, provided important information about the unique electrochemical behaviour of Ca 2+ -CTA 1:1 complex at pH= 8.2. 28,29 Fig .…”

“…In the case of l-anilino-8-naphthalenesulfonate (ANS) 52 and 2-p-toluidino-6-naphthalenesulfonate (TNS) 53 the lipophilic residue of the guest is included inside the calixarene cavity. 54 A cationic calix [4]arene derivative (30) binds both aliphatic (31, 32) and aromatic, sulfonate (23) and carboxylate (26) anions in aqueous solution with a Log K of 1.50, 1.48, 2.44, 2.32, respectively, as a result of concerted electrostatic and hydrophobic interactions. The sulfonate ion in guest 23 may show good electrostatic interaction with the cations on the top of the cavity.…”

Removal of Chromium Anions with Nanofiltration-Complexation by Using p-Sulfonated Calix[4]arene

“…For such a purpose, water soluble ligands can be used in the case of NF-complexation association. For example, watersoluble calix [4]arene-bis(benzocrown-6) has been used in nanofiltration-complexation for cesium [13].…”