Enantiomer‐Selectivity for Phenylethylammonium Ion of Membranes Based on a Chiral Macrocyclic Polyether

Abstract

SummaryA chiral macrocyclic crown ether exhibits an enantiomer-selectivity of 2.6 for u -phenylethylammonium ion when incorporated in solvent polymeric membranes. The sequence of selectivity of these membranes clearly differs from that of lipophilicity for the different biogenic ammonium ions studied, indicating a significant structural contribution.Chiral macrocyclic polyethers which bind chiral ammonium ions with high enantiomer-selectivity and behave as ionophores have been described [ 1-31. The enantiomer-selectivity of such ligands can easily be determined quantitatively by using an electrochemical procedure described earlier [4] [ 5 ] . Here we report on such studies using the ion carrier 1 (Scheme) [6] in solvent polymeric membranes and phenylethylammonium ions as substrates in aqueous solutions contacting the membrane. Scheme 3The selectivities KF&, presented in Figure 1 indicate the preference of the ions J relative to the (k )-u-phenylethylammonium ion by the membrane. In contrast to other ionophores described (see 2 and 3 in Fig. I), 1 induces a rather high selectivity for PEA+ over ephedronium (EPH+) and pseudo-ephedronium 0018-019X/81/3/0657-05$01.00/0 0 1981 Schweizerische Chernische Gesellschaft

Elaboration of a chiral 20‐crown‐6 from a glucofuranose derivative and its complex formation with alkali cations

“…Diethylene glycol-di-( 1,2-0-isopropylidene-a-Dglucofuranos-3-yl) 5 (1.26 g, 2.5 mmol) dissolved in a mixture of dichloromethane (10 mL) and triethylamine (3 mL) was treated with triphenylmethyl chloride (1.38 g, 5.0 mmol) and stirred for 5 hours at room temperature. The reaction mixture was washed successively with water (10 mL), 2M HCl (10 mL), and 10% aq NaHCO, solution (10 mL), dried over anhydrous Na2S04, and evaporated to dryness.…”

“…Enantiomer selectivity of the chiral crown ethers was evaluated by a membrane electrode method [5,6].…”

Discrimination among Octylamine Isomers by Polymeric Membrane Electrodes Based on Lipophilic Calix[6]arene Tetraester Derivatives

“…[1][2][3][4][5][6][7][8][9][10][11] Many of these inorganic cation-selective electrodes exhibit excellent selectivity for analyte cations and are now commercially available. [12][13][14][15][16] For organic cation-ISEs based on derivatives of crown ether or natural ionophore, as reported thus far, there are not many of these ISEs that respond strongly enough to discriminate among organic guests, and the selectivities of these electrodes are mostly controlled by the lipophilicity of the guest. [7][8][9][10][11][12][13][14][15][16][17][18] Recently, calixarenes have received considerable attention as an interesting class of ionic and molecular binding hosts, 19,20 and studies show that various functionalized calixarenes are selective host molecules for cations as well as anions.…”

“…[12][13][14][15][16] For organic cation-ISEs based on derivatives of crown ether or natural ionophore, as reported thus far, there are not many of these ISEs that respond strongly enough to discriminate among organic guests, and the selectivities of these electrodes are mostly controlled by the lipophilicity of the guest. [7][8][9][10][11][12][13][14][15][16][17][18] Recently, calixarenes have received considerable attention as an interesting class of ionic and molecular binding hosts, 19,20 and studies show that various functionalized calixarenes are selective host molecules for cations as well as anions. [21][22][23][24][25][26][27][28][29][30][31][32] The well-defined structure of the calixarene cavity could also be investigated for inclusion of organic guests.…”

Selectivity in the binding and detection of charge diffuse ions

“…With the exception of certain nelectron rich macrocyclic ligands (4,5), most of the neutral ionophores that have been developed to bind ammonium ions only complex primary ammonium ions. Chiral crown ethers, for example, bind certain arylammonium ions enantioselectively (6,7,8), but the chemoselectivity is modest (severe interference from Na+ or K+) and N-alkylation compromises the N-H ... 0 hydrogen bonding. …”