75507-17-4Relevant academic research and scientific papers
LIPOPHILIC BIS(CROWN ETHER) DERIVATIVES OF 15-CROWN-5 AND 18-CROWN-6 AS NEUTRAL CARRIERS OF ION-SELECTIVE ELECTRODES
Kimura, Keiichi,Ishikawa, Atsuo,Tamura, Hiroshi,Shono, Toshiyuki
, p. 447 - 450 (1984)
Lipophilic bis(crown ethers) containing 15-crown-5 and 18-crown-6 rings were synthesized so as to obtain excellent neutral carriers for K+- and Cs+-selective electrodes, respectively.The K+-selective electrode based on the dodecylmethylmalonate of bis(15-crown-5), (I) (n = 1, R = Me), exhibited eminent electrode properties, proving of great practical use, while the Cs+-selective electrode of the bis(18-crown-6) derivative (I) (n = 2, R = Me) did not give results as good as expected.The electrochemical selectivities of the K+ electrode based on the dodecylmalonate of bis(15-crown-5), (I) (n = 1, R = H), and octadecanoyloxymethyl-15-crown-5 (II) are also discussed.
Synthesis and Alkali-cation Complexing Properties of 12-Crown-4 Derivatives
Miyazaki, Takeshi,Yanagida, Shozo,Itoh, Akira,Okahara, Mitsuo
, p. 2005 - 2009 (1982)
Benzyloxymethyl-12-crown-4, a precursor of hydroxymethyl-12-crown-4, is prepared in an excellent yield by the reaction of 3-benzyloxy-1,2-propanediol with 1,8-dichloro-3,6-dioxaoctane in the heterogeneous t-BuOLi/t-BuOH/LiBr*2H2O reaction system.The hydrogenolysis in the presence of p-toluenesulfonic acid leads to a good yield of hydroxymethyl-12-crown-4.The sandwich-type 2:1 complexation with Na+ of 12-crown-4 and hydroxymethyl-12-crown-4 derivatives was discussed on the basis of the stability constants and the solvent extraction in the CH2Cl2-water system.
Synthesis of lipophilic lariat ethers with pendant N-(X)sulfonyl carboxamide groups
Hu, Hui,Bartsch, Richard A.
, p. 557 - 562 (2007/10/03)
Synthetic routes to sixteen lipophilic lariat ether N-(X)sulfonyl carboxamides with X = trifluoromethyl, methyl, phenyl, and p-nitrophenyl are described. For this new family of proton-ionizable lariat ethers in which the acidity can be 'tuned' by X group variation, the ring size is systematically varied from 12-crown-4 to 14-crown-4 to 15-crown-5 to 18-crown-6.
Molecular Recognition Directed Self-Assembly of Tubular Liquid Crystalline and Crystalline Supramolecular Architectures from Taper Shaped (15-Crown-5)methyl 3,4,5-Tris(p-alkyloxybenzyloxy)benzoates and (15-Crown-5-)methyl 3,4,5-Tris(p-dodecyloxy)benzoate
Johansson, Gary,Percec, Virgil,Ungar, Goran,Abramic, Darija
, p. 447 - 460 (2007/10/02)
The syntheses and characterization of a series of (15-crown-5-)methyl 3,4,5-tris(p-alkyloxybenzyloxy)benzoates with alkyl tails of four 25, six 26, and twelve 27 carbon atoms and of (15-crown-5-)methyl 3,4,5-tris(p-dodecyloxybenzoate) 28 are described.Complexation of the crown ether endo-receptor with NaCF3SO3 destabilizes the crystalline phase of 25, 26, 27 and 28 and induces for the case of 27 and 28 the self-assembly of a supramolecular cylindral channel-like architecture which displays a thermotropic hexagonal columnar (Φh) mesophase.Most remarkably, in the crystalline phase of the complexes of 27 with NaCF3SO3 the cylindrical structure of the Φh mesophase is maintained.Characterization of these supramolecular architectures was performed by a combination of differential scanning calorimetry (DSC), thermal optical polarized microscopy, X-ray scattering and molecular modelling.A model is proposed in which a stratum of the column is formed by six molecules of 27 and 28 with the crown ether receptors residing in the column centre and the alkyl tails radiating toward the column periphery. endo-Recognition generated via the (15-crown-5)methyl receptor upon complexation, and exo-recognition provided by the tapered 3,4,5-tris(p-dodecyloxybenzyloxy)benzoate and 3,4,5-tris(p-dodecyloxy)benzoate fragments of 27 and 28 provide the driving force for the self-assembly of this cylindrical supramolecule.
Liquid-Liquid-Extraction of Metal Ions with Lariat Ethers
Gloe, K.,Muehl, P.,Beger, J.,Poeschmann, C.,Petrich, M.,Beyer, L.
, p. 413 - 421 (2007/10/02)
Lariat ethers of various ring size and substitution are synthesized and characterized by physical data and chemical analysis.The extraction behaviour of the crown compounds towards Na+, K+, Cs+ and Ag+ in a picric acid solution has been investigated.The extraction constants for 1:1 and 1:2 complexes are determined using the equilibrium distribution data.The results show that the flexible side chain in the investigated compounds has in no case a positive effect on the metal picrate extraction.
A CONVENIENT SYNTHESIS OF CROWN AND AZACROWN ETHERS WITH PENDANT OXIRANE GROUP
Belohradsky, Martin,Stibor, Ivan,Holy, Petr,Zavada, Jiri
, p. 2500 - 2507 (2007/10/02)
Synthesis of 4,5-epoxy-2-oxa-1-pentylcrown (I) and N-(2,3-epoxy-1-propyl)azacrown ethers (II) from accessible materials is described.
Enhancement of Cation Binding in Lariat Ethers Bearing a Methyl Group at the Quaternary, Pivot Carbon Atom
Nakatsuji, Yohji,Nakamura, Tetsuya,Okahara, Mitsuo,Dishong, Dennis M.,Gokel, George W.
, p. 1237 - 1242 (2007/10/02)
A number of carbon-pivot lariat ethers have been prepared and compared, with their counterparts having a methyl group bonded to the side-arm-bearing or pivot carbon.All of the compounds examined are 15-crown-5 derivatives, and in this series, the methyl lariats invariably show a higher affinity for sodium than do the nonmethylated species.The results are less consistent in the case of potassium cation which is larger than the 15-crown-5 compound's cation binding hole.The enhanced stability constant observed for sodium with the methyl lariats is attributed to reduced s ide-arm mobility or conformational changes in either the side arm or macroring.
Neutral Ligands with Surfactant-Type Structure - Synthesis, Complexation, and Ion Transfer
Weber, Edwin
, p. 770 - 801 (2007/10/02)
New lipophilic neutral ligands which combine crown ether and podand characteristics with structural features of surfactants (cf. formulas 1-12, 16-26) were synthesized.Their complexation behaviour was studied, their solid-to-liquid and liquid-to-liquid phase transfer properties as well as their efficiency in ion transport across a liquid model membrane.Crystalline stoichiometric complexes of the cycles 2a-4a and of 3e with NaSCN, Ba(SCN)2, and BaI2 can be isolated.Among the noncyclic representatives a crystalline complex is obtained only from 11 with BaI2.The ligand 8d behaves in aqueous solution as a typical surfactant showing micelle formation and cloud point.
Crown Cation Complex Effects. 20. Syntheses and Cation Binding Properties of Carbon-Pivot Lariat Ethers
Dishong, Dennis M.,Diamond, Craig J.,Cinoman, Michael I.,Gokel, Geoge W.
, p. 586 - 593 (2007/10/02)
In an effort devise synthetic cation binders that will mimic the behavior of naturally occuring ionophores such as valinomycin, we have prepared approximately 30 macrocyclic (crown) polyethers bearing flexible side chains attached to the macro ring at carbon.In many of these "carbon-pivot" compounds, the side chain contains one or more neutral donor groups that, if in a suitable geometrical arrangement, may provide additional solvation to the macro-ring-bound cation.Although such donors often enhanced the cation binding ability, overall, the increases in stability constants were modest.The physical resemblance and concept of "roping and tying" the cation suggest the name "lariat ethers".Syntheses of these molecules and binding by them of Na+ and K+ cations are reported and conclusions drawn about the structural requirements and cation binding efficacy of these materials.
