- Azo and azoxythiacrown ethers: Synthesis and properties
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A series of 16- and 18-membered azo- and azoxythiacrown ethers have been synthesized by reductive macrocyclization of the respective bis(nitrophenoxy) oxaalkanes. The aromatic residues located in the polyether region of the molecule were introduced to mac
- Kertmen, Ahmet,Szczygelska-Tao, Jolanta,Chojnacki, Jaros?aw
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- A new class of flavonoids bearing macrocyclic polyethers by stereoselective photochemical cycloaddition reaction
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A new class of flavonoids bearing cyclic polyethers involving a phenyl ring was conveniently provided by the intramolecular photochemical dimerization of 2-chromonecarboxylic esters. Irradiation of 2-chromonecarboxylate with a polyether tethered at both ends promoted intramolecular [2 + 2] cyclobutane formation leading to 14- to 27-membered cyclic polyethers. The efficiency depended on the substituted position of the phenyl ring, with ortho- and meta-substituted derivatives giving cycloadducts in good chemical yields and quantum efficiencies, whereas the para-derivatives were inert toward photolysis. X-ray crystallographic analysis revealed that the stereochemistry of the macrocyclic cycloadducts exhibited C2-symmetry.
- Ishikawa, Hiroki,Uemura, Naohiro,Taira, Ryo,Sano, Kento,Yoshida, Yasushi,Mino, Takashi,Kasashima, Yoshio,Sakamoto, Masami
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- Macrocyclic bis-urea receptor: Synthesis, crystal structure and phosphate binding properties
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A macrocyclic bis-urea receptor (L1) and two acyclic bis-urea analogues (L2 and L3) have been synthesized. The crystal structure of L1 was obtained. The experimental results show that the receptor L1 has high selectivity to H2PO4 ?. Meanwhile, compared with the acyclic receptors L2 and L3, L1 has higher binding ability to H2PO4 ?. The results of density functional theory (DFT) calculations deepened our understanding on L1 conformations stability and its anion-binding property.
- Shu, Xi,Wang, Ruyu,Fan, Yu,Li, Shoujian,Huang, Chao
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- Copper(ii) and cobalt(ii) complexes based on bis-benzimidazolyl ligand with 1,2-bis(2′-ethoxy)phenyl linker: Synthesis, crystal structure and conformations
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Seven Cu(ii) and Co(ii) complexes [Co(L)2(H2O) 2]Cl2 (1), [Cu(L)Cl2]2 (2), [Cu(L)(NO3)2]2 (3), [Cu(L)(SO 4)]2 (4), [Co(L)(LA/sub
- Liu, Qing-Xiang,Bi, Yue,Zhao, Xiao-Jun,Zhao, Zhi-Xiang,Wang, Jian-Hua,Wang, Xiu-Guang
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- Revisiting Hydroxyalkylation of Phenols with Cyclic Carbonates
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Described is a tetrabutylammonium fluoride-mediated hydroxyalkylation reaction of phenols with cyclic carbonates. This operationally simple method enables the synthesis of a variety of aryl β-hydroxyethyl ethers in good to excellent yields with a very small amount of catalyst loading (0.1–1 mol%). Of particular note is the efficient conversion of aromatic diols and phloroglucinol to the corresponding bis- and tris-hydroxyethylated products. To further showcase the versatility of this protocol, guaifenesin was prepared with a single step by the condensation of guaiacol and glycerol carbonate. We also developed a flow ethoxylation process permitting the continuous synthesis of multiflorol. (Figure presented.).
- Kao, Shih-Chieh,Lin, Yi-Ching,Ryu, Ilhyong,Wu, Yen-Ku
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supporting information
p. 3639 - 3644
(2019/07/10)
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- Rapid and scalable synthesis of chiral porphyrin cage compounds
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An improved and scalable synthetic route to chiral porphyrin cage compounds, which will be used as catalytic machines for the encoding of information into polymers, has been developed. The porphyrin cage was made chiral by introducing one or two nitro gro
- Gilissen, Pieter J.,Swartjes, Anne,Spierenburg, Bram,Bruekers, Jeroen P.J.,Tinnemans, Paul,White, Paul B.,Rutjes, Floris P.J.T.,Nolte, Roeland J.M.,Elemans, Johannes A.A.W.
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p. 4640 - 4647
(2019/07/12)
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- Two cyclotriveratrylene metal-organic frameworks as effective catalysts for Knoevenagel condensation and CO2 cycloaddition with epoxides
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By using a novel imidazole-functional cyclotriveratrylene ligand, two isostructural frameworks, [Cd3(HECTV)(bdc)3]·DMF·6H2O (1) and [Zn3(HECTV)(OH-bdc)3]·3DMF·4H2O (2) (HECTV = 5,6,12,13,19
- Kang, Da-Wei,Han, Xue,Ma, Xin-Jun,Liu, Ying-Ying,Ma, Jian-Fang
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p. 16197 - 16204
(2018/11/30)
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- Formation and uses of europium complexes
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The present invention provides a method of forming an oxidatively-stable aqueous Eu(II) complex by synthesizing ligands that coordinate to large, soft, electron rich metals like Eu(II). The invention also provides an oxidatively stable aqueous Eu(II) complex. The complex can be used for a variety of purposes some of which include, but are not limited to, in paramagnetic chemical exchange saturation transfer, as a medical diagnostic, as a semiconductor, and for use in forming materials.
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Page/Page column 11
(2017/09/07)
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- Synthesis and extraction properties of some lariat ethers derived from the spontaneously resolved guaifenesin, 3-(2-methoxyphenoxy)propane-1,2-diol
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Capable of spontaneous resolution rac-3-(2-methoxyphenoxy)propane-1,2-diol, guaifenesin 1 has been proposed as a cheap and readily available enantiopure precursor for the synthesis of nonracemic crown ethers having ligating OAr and OMe arms (lariat ethers). The crowns studied failed to form stable host/guest complexes with amine hydrochloride salts; the effective complexation was achieved using hexafluorophosphate salts. Moderate enantiomeric recognition of R*NH2·HPF6 was achieved with the lariat ethers 11c. As a whole, the enantioselectivity of the extraction is inversely related to the extractive power of the lariat ether. ARKAT-USA, Inc.
- Bredikhina, Zemfira A.,Eliseenkova, Rimma M.,Fayzullin, Robert R.,Novikova, Viktorina G.,Kharlamov, Sergey V.,Sharafutdinova, Dilyara R.,Latypov, Shamil K.,Bredikhin, Alexander A.
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experimental part
p. 16 - 32
(2011/09/21)
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- Oxidatively stable, aqueous europium(II) complexes through steric and electronic manipulation of cryptand coordination chemistry
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A series of cryptands has been prepared and they demonstrate the relationship between oxidative stability of aqueous EuII and ligand properties (see figure). One of these EuII complexes is more stable than FeII in hemoglobin and appears to be the most oxidatively-stable aqueous EuII species known. The high stability of EuII is expected to enable the use of the unique magnetic and optical properties of this ion in vivo.
- Gamage, Nipuni-Dhanesha H.,Mei, Yujiang,Garcia, Joel,Allen, Matthew J.
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supporting information; experimental part
p. 8923 - 8925
(2011/02/23)
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- Aromatic ethers and process for producing aromatic ethers
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According to a production process, aromatic ethers are producible by reacting phenols with an oxirane compound with use of an anion exchange resin as a catalyst. According to another production process, aromatic ethers having an alcoholic hydroxyl group are producible by a crystallization-purification step of using a solvent having a solubility parameter ranging from 7.5 to 12.5 for purification by crystallization. Further, according to still another production process, producible are aromatic ethers having an alcoholic hydroxyl group, wherein the content of a metal in the aromatic ethers is less than 100 ppm by mass, and the content of a halogen element in the aromatic ethers is less than 100 ppm by mass.
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- Synthesis of new chiral diaza 18-crown-6-ethers from chiral amines
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Practical syntheses of versatile building blocks of crown ethers 1 and 2, chiral amine precursors 3-6 and chiral diaza 18-crown-6 ethers 7-12 are reported starting from chiral amines.
- Demirel, N.,Turgut, Y.,Hosgoeren, H.
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p. 1047 - 1055
(2007/10/03)
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- A practical synthesis of benzocrown ethers under phase-transfer catalysis conditions
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Convenient and effective procedures for the synthesis of benzo-12-crown-4, benzo-15-crown-5, benzo-18-crown-6, benzo-21-crown-7 and benzo-24-crown-8 under phase-transfer catalysis conditions have been developed.
- Bogaschenko, Tatyana,Basok, Stepan,Kulygina, Catherine,Lyapunov, Alexander,Lukyanenko, Nikolay
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p. 2266 - 2270
(2007/10/03)
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- Substitution effect, absorption, and fluorescence behaviors of 11,12-benzo-1,7,10,13-tetraoxa-4-azacyclopentadec-11-ene (Benzoaza-15-crown-5) derivatives upon cation complexation in solvent extraction
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Substitution effect, absorption, and fluorescence behaviors of some benzoaza-15-crown-5 derivatives upon cation complexation in solvent extraction were studied. The introduction of a substituent on the nitrogen atom in benzoaza-15-crown-5 enhanced extractabilities in the solvent extraction of aqueous alkali metal picrates. The nondonating substituents raised the cation selectivity for Na+ over K+, but the donating substituents reduced the cation selectivity. The absorption and fluorescence spectral behavior was different with the alkali metal cations.
- Nakamura, Mitsunobu,Yokono, Hideaki,Tomita, Ken-Ichi,Ouchi, Mikio,Miki, Masamichi,Dohno, Reizo
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p. 3533 - 3536
(2007/10/03)
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- Facile synthesis of mono and dibenzo N,N-disubstituted diaza 18-crown-6 derivatives
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This study represents a facile synthesis of building blocks (1-3) of crown ethers and amine precoursers (4a-d). The study also involves synthesis of mono and dibenzo N,N-disubstituted diaza 18-crown-6 derivatives with high yield without chromatographic pu
- Topal,Demirel,Togrul,Turgut,Hosgoeren
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p. 281 - 284
(2007/10/03)
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- Studies on quinones. Part. 33. Synthetic approach to podands containing quinone fragments
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The preparation and oxidative demethylation attempts of podands 3-5, and 9 containing the 2,5-dimethoxyphenyl substituent are described. The reaction of alizarine 13 with chloroethanol afforded compounds 14 and 15. The pathway formation of heterocycle 15 from 14 is proposed. The synthesis of podand 16 containing the cytotoxic 1-hydroxy-9,10-anthraquinone fragment as the terminal groups is reported.
- Valderrama, Jaime A.,Leiva, Hilda,Tapia, Ricardo
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p. 737 - 749
(2007/10/03)
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- Radiochemical stability of the dicyclohexano-18-crown-6 ether (DCH18C6): Synthesis and tests in radioactive medium of the DCH18C6 radiolytic products
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The cis-syn-cis isomer of the dicyclohexano-18-crown-6 ether (DCH18C6) was subjected to hydrolysis and radiolysis with a 137Cs gamma source, at different doses of irradiation. The cis-syn-cis DCH18C6 radiolytic products previously identified [1], were synthesized in their different configurations. These radiolytic products, all of cis configuration, were tested on aqueous synthetic solutions of spent nuclear fuels. Experiments in radioactive medium showed that, under continuous extraction conditions, the cis-syn-cis DCH18C6 radiolytic products cannot perturb a reprocessing process using the DCH18C6 as selective extractant. Good prospects for the application of DCH18C6 to spent nuclear fuel reprocessing were therefore demonstrated. An X-ray crystallographic study of the DCH18C6 cis-syn-cis-isomer with uranyl nitrate was investigated. Elsevier,.
- Draye, Micheline,Favre-Reguillon, Alain,Chomel, Rodolph,Faure, Rene,Guy, Alain,Foos, Jacques,Lemaire, Marc
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p. 183 - 197
(2007/10/03)
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- Extractant for selectively extracting strontium from aqueous solution containing the same
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An extractant for selectively extracting strontium from an aqueous solution containing the same, which comprises a 1,2-benzenebis(1,4-dioxanonyl-6,8-dionato)metal complex of the following structural formula: STR1 wherein M represents a metal ion of Cu (II), Zn (II) or Ni (II).
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- Concave Reagents, 15. New Concave 1,10-Phenanthrolines: Catalysts for the Alcohol Addition to Ketenes and Ligands in Transition Metal Complexes
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By bridging tetrahydroxy-1,10-phenanthrolines 9 by ditosylates 10 or diiodides 11 concave 1,10-phenanthrolines 1 were synthesized.Their concave shape was proven by X-ray analyses of 1a and 1c, their basicities were determined by photometric titrations.Compounds 1a-g are active in the base-catalyzed addition of alcohols to ketenes and form stable metal ion complexes with transition metal salts. - Key Words: Macrocycles / Broensted plot / Catalysis, base / Basicity / Transition metal complexes
- Luening, Ulrich,Mueller, Michael,Gelbert, Markus,Peters, Karl,Schnering, Hans Georg von,Keller, Manfred
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p. 2297 - 2306
(2007/10/02)
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- Synthesis of Odd-Numbered 13-Crown-4 Derivatives Possessing a Functional Group and Their Application in C-Lithiation of Acrylates
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The synthesis of symmetrically hydroxy-substituted 13-crown-4 derivatives 2 and 3 is reported.To this end, diol 7 is first deprotonated with potassium tert-butoxide and then treated with ditosylate 6 in the presence of lithium perchlorate as a template.Ba
- Jatzke, Harald,Schmidt, Richard R.
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p. 753 - 758
(2007/10/02)
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- SYNTHESIS AND ALKALI METAL CATION COMPLEXATION BY BENZOCROWN ETHERS
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New or improved synthetic routes to several benzocrown ethers and alkali metal picrate extraction data for eight benzocrown ethers with varying sizes are reported.
- Czech, Bronislaw P.,Czech, Anna,Knudsen, Brian E.,Bartsch, Richard A.
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p. 717 - 722
(2007/10/02)
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- Multiple Benzo-fused Crown Ethers - Synthesis, Ion Selectivities in Membrane Electrodes and Inclusion of Water
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New oligo-benzo-condensed crown-6 ligands 4, 6 - 9 having a different gradation of lipophilicity and of molecular rigidity are synthesized.For the known ligands 3 and 5 of similar constitution improved methods of preparation are described.The carrier efficiencies and ion selectivities of the various ligands for alkali and alkaline earth metal ions in liquid membrane electrodes of different composition are determined and discussed on the basis of the potentiometric selectivity factors lgKPotMgM.The possible behaviour of the new macrocycles in molecular inclusion is studied.A stable crystal lattice inclusion compound of 4 with water of composition 4*1/2 H2O is obtained.
- Weber, Edwin
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p. 4439 - 4452
(2007/10/02)
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- Calcium ionophores as cardiac stimulants. I. Diacids derived from dibenzo crown ethers
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A series of calcium chelating agents has been prepared based on carboxylic derivatives of open chain 18-Crown-6 analogues. Most of these are efficient calcium binding agents, many form lipophilic calcium complexes, and some of these are capable of releasing Ca2+ from liposomes by ionophore action. The best of these is 1,2-bis-[2-(1-carboxydecyloxy)phenoxy]ethane. This compound is cardiotonic in vitro but in the dog vasoconstriction it is the predominant biological effect.
- Ball,Cooper,Main
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p. 137 - 143
(2007/10/02)
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- Synthesis of Three Series of Diastereoisomeric Bicyclic Crown Ethers and their Stability Constants with Group 1A Cations
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The syntheses of a series of bridged crown ethers are described.Their binding strength to group 1A metals has been compared by determination of the stability constants: an explanation for the wide variation of the measured stability constants is given in terms of the influence of steric interactions on the conformation of the isomers and electrostatic effects occurring within the cavity.
- Parsons, David G.
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p. 1193 - 1198
(2007/10/02)
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- Anticoccidial activity of crown polyethers
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Anticoccidial activity in vitro against Eimeria tenella is reported for crown polyethers with ring sizes from 14 to 30 atoms. The most potent compounds, 4 and 9, were found active at 0.33 ppm, but none were active in vivo. Test results are discussed in te
- Brown,Foubister
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p. 590 - 592
(2007/10/02)
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- NEW LIPOPHILIC IONIZABLE CROWN ETHERS
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Two new ionizable crown ethers which bear lipophilic groups are synthesized and found to exhibit selectivity for complexation of K(1+) in competitive solvent extractions of alkali metal cations.
- Czech, Bronislaw,Kang, Sang Ihn,Bartsch, Richard A.
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p. 457 - 460
(2007/10/02)
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- SYNTHESIS OF NITRO AND AMINO DERIVATIVES OF THE MACROCYCLIC POLYETHER 2,3-BENZO-1,4,7,10,13,16-HEXAOXACYCLOOCTADEC-2-ENE
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Convenient methods were developed for the synthesis of 1,2-di(2-hydroxyethoxy)benzene, 1,2-di(2-hydroxyethoxy)-4-nitrobenzene, and 1,2-di(2-hydroxyethoxy)-4,6-dinitrobenzene - the intermediate products in the synthesis of nitro and amino derivatives of 2,3-benzo-1,4,7,10,13,16-hexaoxacyclodec-2-ene (benzo-18-crown-6).The effect of the nature of the solvent on the yield of mono- and dinitro derivatives of 1,2-di(2-hydroxyethoxy)benzene in the nitration of the latter was investigated.It was shown that benzo-18-crown-6 and dicyclohexyl-18-crown-6 have a catalytic effect on the yield of the products from O-alkylation of 1,2-dihydroxybenzene and its derivatives.
- Abakumova, N. I.,Kolenko, I. K.,Kodess, M. I.
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p. 1305 - 1307
(2007/10/02)
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- A NEW SYNTHETIC IONOPHORE EXHIBITING SELECTIVE Li(1+) TRANSPORT
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A noncyclic polyether, which contains 1,3-propylene oxide chain unit and both 8-quinolyl and o-carboxylphenyl terminal groups, exhibits higly selective transport of lithium ion for sodium and potassium ion species which are all together in aqueous solutio
- Hiratani, Kazuhisa
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p. 1021 - 1024
(2007/10/02)
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