- Solvent Extraction of Lanthanoid(III) Picrates with a Bis(crown ether): Enhanced Extractability through Double-sandwich Complexation
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Solvent extractions of aqueous light lanthanoid(III) picrates (La-Gd) with 1,8-dioxooctamethylenebis(4'-benzo-15-crown-5) 4 were conducted at low ionic strength in the absence of dense background salts.Possessing two crown ether units, the bis(crown ether) gave much higher extractabilities for the lanthanoids than did the reference ligand, 4'-acetylbenzo-15-crown-5 3, or related ligands 15-crown-5 1 and benzo-15-crown-5 2, although the profile of the relative cation-selectivity sequence became flat.Unexpectedly, quantitative solvent extraction studies revealed that the cation:ligand stoichiometry of the complex is not 1:1 but 1:2.This indicates that the enhanced extractabilities and the decreased cation selectivity arise not from the conventional intramolecular sandwich complexation but from the unique bimolecular double-sandwich complexation incorporating four crown ether units wrapping around a partially hydrated lanthanoid ion that has to be shielded effectively from the surrounding organic solvent molecules.
- Inoue, Yoshihisa,Nakagawa, Kazuharu,Hakushi, Tadao
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- Benzo-15-crown-5-Aluminium Chloride Complexes of Unusual Stability
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Among twelve crown ethers of 12, 15, 18, and 21 rings only benzo-15-crown-5 and those with an electron-releasing substituent formed the complexes with aluminium chloride which were stable in methanol.
- Wada, Fumio,Matsuda, Tsutomu
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- Heterogeneous catalytic acylation of benzo crown ether using acetic anhydride
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Benzo-15-crown-5 macrocycle has been acetylated using acetic anhydride and a series of cation exchanged clays. This acetylating method has great advantages such as the significant reduction of the formation of by-products lower price and the possibility of environmental friendly process. Yields as high as 80% for the acetylated compound are reached in short times.
- Biro,Bekassy,Agai,Figueras
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- Lipase-mediated resolution of racemic benzo-15-crown-5 ether derivatives
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Racemic large secondary alcohol, 4'-hydroxyethyl-benzo-15-crown-5-ether, (±)-1 was kinetically resolved in high optical yield by asymmetric transformation with Candida antarctica lipase and Pseudomonas cepacia lipase. (C) 2000 Elsevier Science Ltd.
- Kijima, Tatsuro,Moriya, Takanori,Kondoh, Eiki,Izumi, Taeko
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- EFFECT OF GUEST CATION ON THE PHOTOREACTIVITY OF THE PYRAZINE DERIVATIVES HAVING CROWN ETHER MOIETY
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Irradiation of the acetonitrile solution of 4'-(5,6-dicyanopyrazin-2-yl)benzo-15-crown-5 (1) or 4-(5,6-dicyanopyrazin-2-yl)-1,2-dimethoxybenzene (2) in the presence of triethylamine gave monodecyano-derivative (3 or 4) and bisdecyano-derivative (5 or 6).S
- Tada, Masaru,Hamazaki, Hirohide,Hirano, Hideki
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- Synthesis, metal ion binding, and photochromic properties of benzo- and naphthopyrans annelated by crown ether moieties
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Combining a photochromic chromene with a crown ether moiety results in systems in which photochromism and ionophoric properties could significantly influence each other. In this paper, we report the synthesis of several chromenes annelated by 15(18)-crown
- Paramonov, Sergey V.,Lokshin, Vladimir,Smolentsev, Artem B.,Glebov, Evgeni M.,Korolev, Valeri V.,Basok, Stepan S.,Lysenko, Konstantin A.,Delbaere, Stéphanie,Fedorova, Olga A.
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experimental part
p. 7873 - 7883
(2012/10/08)
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- Studies on the photochemical behavior of N-salicylidenaniline in chloroform
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An N-salicylidenaniline (SA), compound 1 with 15-crown-5 moiety, was synthesized. The time-dependent NMR was used to track its photochromic process. The experimental results showed that ultraviolet irradiation would lead compound 1 to decompose into the corresponding salicylaldehyde and amine in chloroform solution, instead of experiencing a photochromic process. By the same method, the reported photochromic results of other SAs were also corrected.
- Zhao, Liyan,Xia, Wujiong,Gou, Baoquan,Lu, Yu,Yang, Chao,Li, Dazhi
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supporting information; scheme or table
p. 199 - 203
(2012/08/08)
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- Synthesis and characterization of new vic-dioximes with benzo-15-crown-5 derivatives and their nickel(II), copper(II), cobalt(II) complexes
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Benzo-15-crown-5-p-toluidino-glyoxime (1) and N(1-naphthyl)amino-benzo-15- crown-5-glyoxime (2) were synthesized by classical methods. Their structures were confirmed by spectral techniques. Both of them were capable of forming complexes with various metal ions (Co2+, Cu2+ and Ni 2+). The structure of the complexes was confirmed by FT-IR, mass spectra and elemental analyses.
- Battaloglu, Rifat,Pekacar, A. Ihsan,Yildiz, Y. Kemal
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body text
p. 2377 - 2379
(2012/08/27)
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- Acetylation of B15C5 crown ether on Cu modified clay catalysts
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With different copper-clay based catalysts, in the presence of AcCl as acetylation agent, B15C5 crown ether is acetylated in a convenient heterogeneous catalytic procedure. We show here the first heterogeneous catalytic method for crown ether acylation, where the Cu exchanged clay gives the best results using really catalytic amount of catalyst.
- Cseri, Tivadar,Bekassy, Sandor,Bodas, Zoltan,Agai, Bela,Figueras, Francois
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p. 1473 - 1476
(2007/10/03)
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- Preparation and Characterization of Tetraaza[14]annulene and its Nickel(II) and Copper(II) Complexes with Crown Ether Functionalities
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Three new organic hosts are described that contain a tetraaza[14]annulene core to which two crown ether voids are attached. These hosts include a free base tetraaza[14]annulene and/or its complexes with benzo-15-crown-5 rings. The crown tetraaza[14]annulene is synthesized from tetraaza[14]annulene and 4′-chloroformylbenzo-15-crown-5. Its nickel(II) and copper(II) complexes are prepared in a similar manner as above. In solution the compounds do not tend to form aggregates. However, aggregation is affected by the presence of alkali-metal salts, which coordinate to the crowns. Li+ and Na+ cations with diameters that match the diameters of the crown ether rings form 1:2 host-guest complexes. Complexes with 2:2 host-guest stoichiometry are formed when the diameters of K+ and Cs+ cations exceed that of the crown ether rings. Nevertheless, it is weak for the present macrocycle and its complexes to be inclined to form dimers owing to the steric hindrance of the substituent groups and owing to restraining the rotation of the carbonyl bond connecting the crown ether group.
- Sakata, Kazunori,Shimoda, Manabu,Hashimoto, Mamoru
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p. 1593 - 1598
(2007/10/03)
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- Preparation and application of 4'-carboxybenzo-15-crown-5, a drift-type crown ether phase transfer catalyst
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A new "drift-type" crown ether phase transfer catalyst, 4'-carboxybenzo-15-crown-5 adsorbed on poly(styrene/divinylbenzene)-NR2 resin, was synthesized and applied to catalyze the oxidation of benzhydrol with NaMnO4 as an oxidant. Before the reaction, the drift-type crown ether catalyst was adsorbed on the resin with ion-pair (resin-NR2H+-O2C-monobenzo-15-crown-5) formation. During the reaction period the crown ether catalyst was released from the resin into the reaction solution as a homogeneous catalyst by adjusting the acidity of the solution to 10-1 M HCl to destroy the ion pair between the catalyst and the resin. After the reaction, the crown ether catalyst could be readsorbed on the resin by adjusting the concentration of HCl to 10-5 M and could be readily recovered by filtration. The catalyst, 4'-carboxybenzo-15-crown-5, was found to be a more effective catalyst than other crown ethers, such as 15-crown-5, 18-crown-6, monobenzo-15-crown-5, and dibenzo-18-crown-6.
- Chou, Ming-Seng,Shih, Jeng-Shong
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p. 1614 - 1620
(2007/10/02)
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- Synthesis of 4'-Vinylbenzo-3n-crown-n Ethers (4<=n<=10)
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4'-Vinylbenzo-3n-crown-n ethers (4=n=10) are prepared by a "Cs-templated" cyclization reaction of catechol with dimesylates of oligoethylene glycols, acetylation of the resultant benzo-3n-crown-n ethers (4=n=10), reduction of the acyl group, and dehydration of the resultant alcohols with pyridinium tosylate.
- Talma, Auke G.,Vossen, Huib van,Sudhoelter, Ernst J. R.,Eerden, Johan van,Reinhoudt, David N.
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p. 680 - 683
(2007/10/02)
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- The Photochemistry of the Host-Guest Complex. VII. The Photoreaction of Dicyanopyrazine Derivatives Having a Crown Ether Moiety
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The irradiation of 4'-(5,6-dicyano-2-pyrazinyl)benzo-15-crown-5 and 5,6-dicyano-2-(3,4-dimethoxyphenyl)pyrazine in the presence of a tertiary or secondary amine caused reductive decyanation to give 5-decyano derivatives, which in turn gave bis(decyano) derivatives on further irradiation.Free-energy changes upon single-electron transfer from the amine to the excited state of dicyanopyrazine derivatives are exothermic for triethylamine and diethylamine, but endothermic for butylamine.The single-electron transfer was evidenced by the effect of the sodium ion on the quantum yields of the reaction products and the fluorescence quenching.
- Tada, Masaru,Hamazaki, Hirohide,Hirano, Hideki
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p. 3865 - 3869
(2007/10/02)
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- Photochemistry of Host-Guest Complex.III. Effect of Guest Cation on the Photoreactivity of Acetophenone Oxime Derivatives Having Crown Ether Moiety
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The syn-anti isomerisation of acetylbenzocrown ether oximes was stimulated by the complex-formation with sodium ion.The photolysis of these oximes gave mother ketones and amides through an oxaziridine intermediate.The photolysis of the oximes was depressed by the formation of host-guest complexes.Reactivity in the photolysis of the crown ether oximes corresponds to that 3,4-dimethoxyacetophenone oxime, whereas the reactivity of the complexed crown ether oxime with sodium ion corresponds to that of p-cyanoacetophenone oxime.Such behavior is explained by the change of the electronic properties of excited states of acetophenone oxime chromophore, which enhances the intersystem crossing.
- Tada, Masaru,Hirano, Hideki,Suzuki, Atsushi
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p. 2304 - 2308
(2007/10/02)
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- Modified Crown Ether Catalysts. 2. Synthesis of Alkanoyl-, Aroyl-, α-Hydroxyalkyl- and Alkylbenzo and Alkylcyclohexano Crown Ethers
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Improved procedures for the synthesis and purification of alkanoyl- and aroylbenzo crown ethers are reported.Several new alkanoyl- and α-hydroxyalkylbenzo crown ethers were prepared.Alkylbenzo crown ethers were prepared in high yield by the Raney nickel catalyzed hydrogen-transfer reductions of the corresponding acyl- or hydroxyalkylbenzo crown ether compounds.The reduction of the tosylhydrazones of acylbenzo crown ethers with sodium borohydride in acetic acid also yielded the corresponding alkyl derivate.Attempted reduction of the acyl- and α-hydroxyalkylbenzo crown ethers by catalytic hydrogenation over palladium catalysts was unsuccessful apparently due to strong binding of the crown ethers to the catalyst.Alkylcyclohexano crown ethers were prepared by catalytic hydrogenation of the aromatic rings of the corresponding alkylbenzo crown ethers.
- Stott, Paul E.,Bradshaw, Jerald S.,Parish, W. Wesley,Copper, James W.
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p. 4716 - 4720
(2007/10/02)
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