Citations with the tag: CROWN ethers

Results 1 - 50

  • Synthesis of the first dibenzo(perhydrotriazino)-aza-14-crown-4 ethers.
    Chuong Hong Hieu; Le Tuan Anh; Levov, A. N.; Nikitina, E. V.; Soldatenkov, A. T. // Chemistry of Heterocyclic Compounds; Nov2009, Vol. 45 Issue 11, p1406 

    A letter to the editor is presented regarding synthesis of the first dibenzo(perhydrotriazino)-aza-14-crown-4 ethers.

  • An original approach to the amination of crown ethers.
    Lyakhovnenko, A. S.; Aksenov, A. V.; Kugutov, M. M. // Chemistry of Heterocyclic Compounds; Dec2010, Vol. 46 Issue 9, p1138 

    A letter to the editor is presented on the issue of amination of crown ethers.

  • Novel method for the acetamination of crown ethers.
    Aksenov, A. V.; Aksenov, N. A.; Nadein, O. N.; Aksenova, I. V. // Chemistry of Heterocyclic Compounds; Feb2011, Vol. 46 Issue 11, p1405 

    A letter to the editor is presented regarding the use of nitroethane-phenylpropanolamine (PPA) for crown ether acetaminations.

  • 3-Oxapentane-1,5-diselenol.
    Vshivtsev, V. Yu.; Levanova, E. P.; Grabel'nykh, V. A.; Sukhomazova, E. N.; Zhanchipova, E. R.; Klyba, L. V.; Albanov, A. I.; Russavskaya, N. V.; Sinegovskaya, L. M.; Korchevin, N. A. // Russian Journal of Organic Chemistry; Oct2007, Vol. 43 Issue 10, p1561 

    The article focuses on the importance of the molecular compound in 3-Oxapentane-1,5-diselenol for the synthesis of efficient complexing ligands, particularly of selenium analogs of crown ethers. The author says that they formerly synthesized 1,3-propanediselenol by reductive cleavage of...

  • Sugar Derived Crown Ethers and Their Analogs: Synthesis and Properties.
    Jarosz, Slawomir; Listkowski, Arkadiusz // Current Organic Chemistry; Apr2006, Vol. 10 Issue 6, p643 

    Receptors with the sugar unit incorporated into the macrocyclic structure - their synthesis and complexing abilities - are reviewed. The receptors with the disaccharide moieties (although such derivatives are rare) including sucrose are also described in this review.

  • Synthesis of supramolecular complexes based on tetracrown-substituted zinc porphyrinates.
    Mikhailitsyna, E.; Tyurin, V.; Beletskaya, I. // Protection of Metals & Physical Chemistry of Surfaces; Nov2010, Vol. 46 Issue 6, p655 

    New metal-porphyrin receptors functionalized by aza-crown-ether groups were synthesized. Main paths of supramolecular self-assembly of porphyrin aza-crown-ether conjugates to bis-porphyrin sandwich complexes with metal and ammonium cations were studied using spectral methods of analysis (EAS, H,...

  • Oxidative coupling of naphtho-9-crown-3 ether: X-ray crystal structure and solution and solid-state NMR analysis of the dimer.
    Buchanan, G W; Rastegar, M F; Yap, G PA; Moghimi, A; Ghandi, M // Canadian Journal of Chemistry; Oct2001, Vol. 79 Issue 10, p1505 

    Treatment of naphtho-9-crown-3 ether with FeCl[sub 3 ] and aqueous H[sub 2] SO[sub 4] generates bis-naphtho-9-crown-3 ether in ca. 30% yield. This compound crystallizes in the monoclinic P2[sub 1] /n space group; a = 9.2004(9), b = 18.0868(17), and c = 13.2078(13) Å, β = 97.799(2)° and...

  • Thermodynamics of complex formation in mixed solvents K and Δ H for the formation reaction of [Gly18C6] at 298.15 K.
    Matteoli, E.; Lepori, L.; Usacheva, T. R.; Sharnin, V. A. // Journal of Thermal Analysis & Calorimetry; Sep2009, Vol. 97 Issue 3, p811 

    The influence of H2O–EtOH and H2O–Acetone mixed solvents at various compositions on the thermodynamics of complex formation reaction between crown ether 18-crown-6 (18C6) and glycine (Gly) was studied. The standard thermodynamic parameters of the complex [Gly18C6] (log K°,...

  • Interlocked molecules: Tangled tetrahedra.
    Cantrill, Stuart // Nature Chemistry; Jun2013, Vol. 5 Issue 6, p442 

    The article reports on the research of a team in Cambridge and Berlin headed by Christoph Schalley, in which they produce an unusual catenane through six crown ethers that were threaded to the edge of a metal-organic tetrahedron.

  • Effect of the Structure and Concentration of Crown Ethers on the Electrodeposition of Cadmium and Nickel from Sulfate Electrolytes.
    Kuznetsov, V.V.; Skibina, L.M.; Levochkin, R.A.; Vertii, I.V. // Protection of Metals; Mar/Apr2003, Vol. 39 Issue 2, p154 

    The effectiveness of crown ethers (CEs) at cadmium was found to mainly depend on the character of metal-additive complexation. The formation of electroactive complexes in the bulk of solution usually facilitates the electrode reaction. In contrast, the interaction of metal ions with adsorbed CE...

  • Urea nitrate, an exceptionally easy-to-make improvised explosive: studies towards trace characterization.
    Tamiri, Tsippy; Rozin, Rinat; Lemberger, Nitay; Almog, Joseph // Analytical & Bioanalytical Chemistry; Sep2009, Vol. 395 Issue 2, p421 

    Urea nitrate is a powerful improvised explosive, frequently used by terrorists in the Israeli arena. It was also used in the first World Trade Center bombing in New York in February 1993. It is difficult to identify urea nitrate in post-explosion debris, since only a very small fraction survives...

  • Crown ethers: From ion recognition to supramolecular function.
    Yadav, G.D. // Chemical Business; Nov97, Vol. 11 Issue 4, p21 

    Reports that combination of crown ether chemistry with other chemicals can create a functional supramolecular systems.

    ZAIYTSEV, S. Yu.; TSARKOVA, M. S.; TIMONIN, A. N.; ZAIYTSEV, I. S.; DMITRIEVA, S. N.; GROMOV, S. P. // Izvestiya Vysshikh Uchebnykh Zavedenii. Seriya Khimiya i Khimich; 2011, Vol. 54 Issue 8, p29 

    The novel method of investigation of the crown-ethers selective to the calcium cations - "method of three solutions" - was developed. By means of those method peculiarities of complexation of some derivatives of crown ethers and calcium cations have been studied. The novel recipe of preparation...

  • Synthesis Of Schiff's Base Ligands By Condensation Of 2-hydroxyacetophenone And Chiral Diamines.
    Agrawala, Manoj Kumar; Kaushik, Manish; Singhalc, Amit // Indian Streams Research Journal; Sep2012, Vol. 2 Issue 8, Special section p1 

    Three optically active Schiff-base ligands 2-4 have been prepared by thermal condensation of 2-hydroxyacetophenone 1 with (1R,2R)-(-)-1,2-diaminocyclohexane, (1S,2S)-(-)- 1,2-diphenylethylenediamine or R-(+)-2,2'-diamino-1,1'-binaphthalene, respectively. The products have been characterized by...

  • Synthesis of novel cyclophane-type crown ethers from 2-methylindole.
    Eshghi, Hossein; Rahimisadeh, Mohammad; Pordel, Mehdi; Bakhtiarpoor, Zahra // Journal of Chemical Research; Oct2013, Vol. 37 Issue 10, p596 

    New indolyl crown ethers were obtained from reaction of bis-indolyl podand with different aldehydes using Fe(HSO4)3 as catalyst. Spectral characterisations and optimised structures of isomers of these new cyclophane-type compounds are also presented.

  • Effect of crown ether ring size on binding and fluorescence response to saxitoxin in anthracylmethyl monoazacrown ether chemosensors.
    Hua Mao; Thorne, John B.; Pharr, Jennifer S.; Gawley, Robert E. // Canadian Journal of Chemistry; Oct2006, Vol. 84 Issue 10, p1273 

    Convenient macrocyclization synthetic routes for the preparation of different-sized monoaza anthracylmethyl crown ether chemosensors (15-crown-5, 18-crown-6, 21-crown-7, 24-crown-8, and 27-crown-9) are described. Evaluation of these crowns as chemosensors for saxitoxin revealed that the larger...

  • Dibenzotetraazamacroheterocycles: Synthesis and properties. (Review).
    Kulikov, O. V.; Pavlovsky, V. I.; Andronati, S. A. // Chemistry of Heterocyclic Compounds; Dec2005, Vol. 41 Issue 12, p1447 

    Data on the synthesis, complexing ability, practical applications, and biological activity of dibenzotetraazamacroheterocycles of the azacrown ether, amide, and azomethinedibenzotetraazacycloalkane types and also dibenzotetraazamacroheterocycles containing amide and azomethine fragments are...

  • Effect of the Structure of Benzo- and Dibenzocrown Ethers on Their Reaction with the Aerosil Surface.
    Zakolodyazhnaya, O.; Litvinova, L.; Kraevskaya, N.; Kotlyar, S.; Kamalov, G. // Theoretical & Experimental Chemistry; Jul2005, Vol. 41 Issue 4, p259 

    The adsorption of 4-substituted benzo- and 5,5'-disubstituted dibenzocrown ethers from benzene by aerosil A-300 was studied. The ethers included a total of 45 compounds with diphenyl oxide, diphenyl, and diphenyl sulfide fragments. Analysis of the Henry coefficients (KH) and the extent of...

  • Collective behaviour of crown channels.
    Vijayvergiya, Viksita; Bose, Debasish; Ghosh, Paramita; Ghosh, Subhendu // European Biophysics Journal; 2003, Vol. 32 Issue 8, p724 

    Collective behaviour of a crown ether channel, bis[(benzo-15-crown-5)-15-yl methyl] pimelate, in a planar lipid bilayer membrane has been studied through electrophysiological methods. A characteristic feature of these channels is their sequential opening, indicated by a uniform stepwise increase...

  • Effect of cyclic benzo-12-crown-4 polyether on copper electrodepsosition from sulfate aqueous ethanol baths.
    Kuznetsov, V. V.; Skibina, L. M.; Geshel', S. V. // Protection of Metals; May2006, Vol. 42 Issue 3, p253 

    It is found that the effectiveness of crown ether (with benzo-12-crown-4 as an example) is a function of the composition of the water-ethanol solvent and the bulk and surface concentration of sulfate anions. An increase in the adsorbability of sulfate anions at Cu in the presence of the crown...

  • Coprecipitation of Trace Amounts of 137Cs and 85Sr with [Na(18-Crown-6]BPh4 from Neutral and Alkaline Solutions.
    Kulyukhin, S.; Konovalova, N.; Rumer, I.; Kamenskaya, A.; Mikheev, N. // Radiochemistry; May2005, Vol. 47 Issue 3, p284 

    Coprecipitation of 137Cs and 85Sr with [Na(18-crown-6]BPh4 solid phase from aqueous, aqueous-ethanolic, and alkaline solutions is studied. 137Cs and 85Sr cocrystallize with [Na(18-crown-6]BPh4 from aqueous and aqueous-ethanolic solutions. The cocrystallization coefficients D of 137Cs and 85Sr...

  • Formation and Decomposition of Potassium Potassides Complexed Crown Ethers in Tetrahydrofuran Solution.
    Grobelny, Zbigniew; Stolarzewicz, Andrzej; Szczepanski, Marcin; Sok�l, Maria // Current Organic Chemistry; Aug2008, Vol. 12 Issue 12, p1040 

    This review systematizes the essential data on alkalide solutions called also alkali metal solutions or blue solutions, i.e. solutions of the salts containing alkali metal anions (M-). It focuses particularly on the formation and decomposition of potassium potassides as well as on the...

  • A novel crown ether generation containing the pyrilium heteroaromatic cation � Synthesis, characterization, and solid-phase 13C NMR.
    Moghimi, Abolghasem; Rastegar, Majid Faal; Ghandi, Mehdi // Canadian Journal of Chemistry; Dec2004, Vol. 82 Issue 12, p1716 

    The synthesis and structural characterization of two members, 5 and 6, of a novel generation of crown ethers containing the pyrilium cation are reported. These two compounds contain two and three benzo-9-crown-3 (B9C3) units, respectively, connected to the 2 and 6 or 2, 4, and 6 positions of a...

  • Macrocyclic effect in extraction of metals by crown compounds containing diphenyloxy spacers.
    Yakshin, V.; Vilkova, O.; Kotlyar, S.; Kamalov, G. // Doklady Physical Chemistry; Oct2007, Vol. 416 Issue 2, p280 

    The article discusses the macrocyclic effect of crown compounds containing diphenyloxy spacers in extraction of metals. Crown compounds were identified using spectroscopy, direct injection and elemental analysis. Results showed that the pseudodihedral angle formed by the benzene rings in the...

  • Application of Crown Ethers as Buffer Additives in Capillary Electrophoresis.
    Elbashir, Abdalla A.; Aboul-Enein, Hassan Y. // Current Pharmaceutical Analysis; May2010, Vol. 6 Issue 2, p101 

    This paper provides an overview of the applications of crown ethers as buffer additive in capillary electrophoresis. The applications area can be categorized into the separation of inorganic cations; chiral separation and separation of organic compounds include positional isomers. The use of...

  • The effect of carbonyl carbon atom replacement in acetone molecule (ACN) by sulfur atom (DMSO).
    J�zwiak, Malgorzata // Journal of Thermal Analysis & Calorimetry; Sep2008, Vol. 93 Issue 3, p701 

    Enthalpies of solution of 1,4-dioxane, 12-crown-4 ether (12C4), 15-crown-5 ether (15C5) and 18-crown-6 (18C6) have been analyzed from the point of view of preferential solvation of these cyclic ethers (crown ethers) by a molecule of acetone or dimethylsufoxide in the mixtures of water with...

  • Composite chemosensor materials based on polymer matrices with crown ether derivatives.
    Zaitsev, I. S.; Tsar'kova, M. S.; Timonin, A. N.; Zaitsev, S. Yu.; Sazonov, S. K.; Vedernikov, A. I.; Gromov, S. P. // International Polymer Science & Technology; 2012, Vol. 39 Issue 6, p59 

    Composite materials, consisting of a polymer matrix and a crown ether derivative immobilised in it, and possessing photochromic properties, have been obtained and investigated. The possibility of using them to detect mercury(II) cations has been shown.

  • Theoretical studies of actinyl crown ether inclusion complexes.
    Martin, Richard L.; Jeffrey Hay, P.; Schreckenbach, Georg // AIP Conference Proceedings; 2000, Vol. 532 Issue 1, p392 

    Clark et al. recently reported the synthesis of the NpO[sub 2][sup +]ion encapsulated by the 18-crown-6 ligand. The [NpO[sub 2](18-crown-6)]ClO[sub 4] salt was characterized crystallographically and shown to have six approximately coplanar crown ether oxygen atoms coordinated to a central...

  • Synthesis of Unconventional Materials Using Chitosan and Crown Ether for Selective Removal of Precious Metal Ions.
    Dhakal, Rabindra Prasad; Oshima, Tatsuya; Baba, Yoshinari // World Academy of Science, Engineering & Technology; Aug2009, Issue 32, p204 

    The polyfunctional and highly reactive bio-polymer, the chitosan was first regioselectively converted into dialkylated chitosan using dimsyl anionic solution(NaH in DMSO) and bromodecane after protecting amino groups by phthalic anhydride. The dibenzo-18-crown-6-ether, on the other hand, was...

  • Construction, synthesis and study of new discotic mesogens.
    Akopova, O. B. // Journal of Structural Chemistry; Jan2006, Vol. 47 Issue 1, p120 

    The calculation and analysis of molecular parameters (MPs) has been carried out for five series of triphenylene derivatives and crown ether derivatives (30 molecules) containing chiral or complexing centers. The values of the MP were used to predict possible occurrence of columnar and nematic...

    PABUÇCU, Köksal; DEMİRİZ, Semsay; BİLGE, Selen; KILIÇ, Zeynel // Anadolu University Journal of Sciences & Technology; 2009, Vol. 10 Issue 1, p185 

    In this study, diaza-crown ether and phosphaze-crown ethers have been investigated in scanning electron microscope (SEM) and compared to their electron micrographs. In analysis of micrograph have been observed that compounds has different morphological structure.

  • Solvent Extraction of Sodium Permanganate by Mono-benzo 3m-Crown-m Ethers (m = 5, 6) into 1 ,2-Dichloroethane and Nitrobenzene: a Method which Analyzes the Extraction System with the Polar Diluents.
    Kudo, Yoshihiro; Harashima, Kyohei; Katsuta, Shoichi; Takeda, Yasuyuki // International Journal of Chemistry; Feb2011, Vol. 3 Issue 1, p99 

    Analytical equations were derived for the extraction of univalent metal salts (MA) by crown ethers (L) into polar diluents. Then, NaMnO4 was extracted at 25 °C by benzo-15-crown-5 and -18-crown-6 ethers (B15C5 and B18C6) from a water (w)-phase into a 1,2-dichloroethane (DCE)-one. So, the...

  • Oxidation of methylphenyl sulfide with hydrogen peroxide in the presence of crown ethers and their complexes with amino acids.
    Tarakanova, A. V.; Baishev, M. Kh.; Rakhmanov, E. V.; Kardashev, S. V.; Anisimov, A. V. // Theoretical Foundations of Chemical Engineering; Aug2010, Vol. 44 Issue 4, p540 

    The oxidation of methylphenyl sulfide, benzothiophene, and dibenzothiophene with hydrogen peroxide in the presence of crown ethers was studied. The major product of the oxidation was methylphenyl sulfoxide. The reaction was retarded by the addition of amino acids, which formed 1: 1 complexes...

  • Kinetics of the adsorption of strontium(II) by a novel silica-based 4,4',(5')-di(tert-butylcyclohexano)-18-crown-6 extraction resin in nitric acid medium.
    Zhang, A.; Wei, Y.-Z.; Kumagai, M.; Koyama, T. // Journal of Radioanalytical & Nuclear Chemistry; Dec2004, Vol. 262 Issue 3, p739 

    A new type of silica-based chelating extraction resin, DtBuCH18C6/SiO2-P, was prepared by impregnating a crown ether derivative, 4,4¢,(5¢)-di(tert-butylcyclohexano)-18-crown-6 (DtBuCH18C6), into the porous silica/polymer composite particles (SiO2-P). The adsorption of Sr(II) and some other...

  • Chiral lariat ethers based on spontaneously resolved 3-(2-cyanophenoxy)propane-1,2-diol.
    Fayzullin, R.; Bredikhina, Z.; Sharafutdinova, D.; Bazanova, O.; Bredikhin, A. // Russian Journal of Organic Chemistry; Apr2014, Vol. 50 Issue 4, p611 

    The article discusses a study on the chiral lariat ethers based on spontaneously resolved 3-(2-Cyanophenoxy)propane-1,2-diol. The study has showed formation of supramolecular complexes by crown ether (R)-III and enantiomers of 1-phenylethanamine hydrochloride IV-HCl. Also offered is a synthesis...

  • Determination of ion-pair formation constants of univalent metal-crown ether complex ions with anions in water using ion-selective electrodes: application of modified determination methods to several salts.
    Kudo, Yoshihiro; Wakasa, Masaomi; Ito, Tomomi; Usami, Jun; Katsuta, Shoichi; Takeda, Yasuyuki // Analytical & Bioanalytical Chemistry; Jan2005, Vol. 381 Issue 2, p456 

    Ion-pair formation constants (mol-1 dm3 unit),KMX for a univalent metal salt (MX) andKMLX for its ion-pair complex (ML+X-) with a crown ether (L) in water, were determined at various ionic strengths (I) and 25°C by potentiometry with ion-selective electrodes for MX=NaPic, NaMnO4, NaBPh4,...

  • A complexation study of 15-crown-5 with Co cation in some pure and mixed organic solvents.
    Sattari, Mahshid; Rounaghi, Gholam; Deiminiat, Behjat; Mohajeri, Massoumeh // Russian Journal of General Chemistry; Mar2014, Vol. 84 Issue 3, p571 

    The stability constant (log K) and the thermodynamic parameters (free energies, enthalpies, and entropies) of the complexation of Co cation with 15-crown-5 (15C5) in acetonitrile-methanol (AN/MeOH), acetonitrile-nitrobenzene (AN/NB), acetonitrile-dichloromethane (AN/DCM) and...

  • Hydrogen peroxide oxidative desulfurization of model diesel mixtures using azacrown ethers.
    Rakhmanov, E.; Baranova, S.; Wang, Zixiao; Tarakanova, A.; Kardashev, S.; Akopyan, A.; Naranov, E.; Oshchepkov, M.; Anisimov, A. // Petroleum Chemistry; Jul2014, Vol. 54 Issue 4, p316 

    Hydrogen peroxide oxidative desulfurization of model diesel fuel mixtures in the presence of azacrown ethers and their complexes with niobium pentachloride at 40-80°C has been studied. It has been found that the use of complexes of azacrown ethers with NbCl leads to a decrease in the total...

  • Synthesis, X-ray crystal structure, and solid-state [sup 13] C NMR study of tris(9-crown-3)triphenylene.
    Buchanan, Gerald W; Rastegar, Majid F; Yap, Glenn PA // Canadian Journal of Chemistry; Feb2001, Vol. 79 Issue 2, p195 

    Benzo-9-crown-3 ether trimerizes in the presence of FeCl[sub 3] and aqueous H[sub 2] SO[sub 4] to produce tris(9-crown-3)triphenylene in 25.4 yield. This compound crystallizes in the monoclinic P2[sub 1] /c space group: a = 13.759(2) Å, b = 13.318(2) Å, c = 13.399(2) Å, β =...

  • Copper Electroplating from Sulfate Electrolytes Containing Crown Ethers.
    Kuznetsov, V.V.; Skibina, L.M.; Geshel', S.V. // Protection of Metals; Mar/Apr2003, Vol. 39 Issue 2, p145 

    It is found that, an excess of copper ions inhibits electroplating due to adsorption of electroactive substance resulting from the interaction of discharging metal ions with crown ester (CE) additive in the surface layer. When the crown ester is in excess, preceding dissociation of complexes...

  • Selective extraction of alkali metals with solutions of dibenzocrown ethers in organofluorine diluents from nitric acid media.
    Yakshin, V. V.; Vilkova, O. M.; Tananaev, I. G.; Smirnov, I. V.; Tsivadze, A. Yu.; Myasoedov, B. F. // Doklady Physical Chemistry; Oct2008, Vol. 422 Issue 2, p271 

    The article presents a study on the new extraction systems based on functionalized crown ethers in organofluorine diluents of alkali metals. The most efficient agents for extraction of metals from nitric acid media are the dicycohexyl derivatives. However, the most available and inexpensive...

  • Assembled nanoparticle films with crown ether–metal ion “sandwiches” as sensing mechanisms for metal ions.
    Russell, Lesley E.; Pompano, Rebecca R.; Kittredge, Kevin W.; Leopold, Michael C. // Journal of Materials Science; Sep2007, Vol. 42 Issue 17, p7100 

    Specialized nanoparticles known as monolayer-protected clusters (MPCs) were affixed with metal selective crown ether (CE) functional groups and assembled into novel thin films to form potential metal ion sensing materials. Films of MPCs modified with potassium specific 15-crown-5 ligands...

  • Host-guest complexes of crown ethers with HN-proton-donor molecules.
    Wang, Wen-Jwu; Ganin, E. V. // Russian Journal of General Chemistry; Dec2004, Vol. 74 Issue 12, p1918 

    Crown ethers were reacted with HN-proton-donor molecules to obtain crystalline molecular host-guest complexes. It was found that complexes with crown ethers of different structure are formed, depending on the linear dimensions and mode of steric shielding of active centers of the proton-donor...

  • Discussion on complexation reactions between dicyclohexyl-18-crown-6 (DCH18C6) with Na+, K+, Cs+, Rb+, and Tl+ metal cations in acetonitrile-water binary mixtures.
    Soorgi, M. H.; Rounaghi, G. H.; Kazemi, M. S. // Russian Journal of General Chemistry; Oct2008, Vol. 78 Issue 10, p1866 

    The complex formation between Na+, K+, Cs+, Rb+ and Tl+ metal cations with macrocyclic ligand, dicyclohexyl-18-crown-6 (DCH18C6) was studied in acetonitrile-water (AN-H2O) binary systems at different temperatures using conductometric method. DCH18C6 forms 1:1 complexes with these metal cations....

  • Thermochemistry of the silver(I) complexation with 18-crown-6 ether in a binary solvent methanol-dimethylformamide.
    Kuz'mina, I.; Sharnin, V.; Golikov, A. // Russian Journal of General Chemistry; Jun2011, Vol. 81 Issue 6, p1078 

    The effect of methanol-dimethylformamide solvent on the reaction enthalpy of the silver(I) complexation with the 18-crown-6 ether was studied using a calorimetric method. Increase in the DMF concentration was found to cause a decrease in the reaction exothermicity. The determining factor in the...

  • Synthesis, complex-formation, and extracting ability of new derivatives of dithia-13(16)-crown-4(5) ethers.
    Tulyakova, E. V.; Rakhmanov, E. V.; Lukovskaya, E. V.; Fedorova, O. A.; Abramov, A. A.; Khoroshutin, A. V.; Bobylyova, A. A.; Anisimov, A. V. // Chemistry of Heterocyclic Compounds; Feb2006, Vol. 42 Issue 2, p206 

    Various methods of synthesizing functional derivatives of dithia-13(16)-crown-4(5) ethers are proposed. Complex-formation of the obtained compounds with Ag+ and Pb2+ ions has been studied using 1H NMR. A radiometric method was used to investigate the extracting ability of substituted...

  • New Synthesis of Formylbenzoazacrown Ethers.
    Dmitrieva, S. N.; Tikhonova, O. V.; Gromov, S. P. // Russian Journal of Organic Chemistry; Sep2005, Vol. 41 Issue 9, p1387 

    A new procedure has been developed for the synthesis of formyl-substituted benzoazacrown ethers via cyclization of halogen derivatives of aza podands by the action of sodium hydride.

  • Use of open-cell resilient polyurethane foam loaded with crown ether for the preconcentration of uranium from aqueous solutions.
    Abou-Mesalam, M. M.; El-Naggar, I. M.; Abdel-Hai, M. S.; El-Shahawi, M. S. // Journal of Radioanalytical & Nuclear Chemistry; Nov2003, Vol. 258 Issue 3, p619 

    The preconcentration of uranium from aqueous solutions on open-cell resilient polyurethane foams (PUF) impregnated with crown ether as an organic extractant in different conditions was investigated. The data showed that 50 minutes is a sufficient time to attain equilibrium with a maximum...

  • Recent Advances in the Synthesis of Ammonium-Based Rotaxanes.
    Thibeault, Dominic; Morin, Jean-François // Molecules; May2010, Vol. 15 Issue 5, p3709 

    The number of synthetic methods enabling the preparation of ammonium-based rotaxanes has increased very rapidly in the past ten years. The challenge in the synthesis of rotaxanes results from the rather weak interactions between the ammonium-containing rod and the crown ether macrocycle in the...

  • Synergistic extraction of Ce(III), Eu(III) and Tm(III) with a mixture of picrolonic acid and benzo-15-crown-5 in chloroform.
    Rehman, Habib-ur-; Ali, Akbar; Anwar, Jamil; Yawar, Wasim // Journal of Radioanalytical & Nuclear Chemistry; Feb2006, Vol. 267 Issue 2, p421 

    The synergistic mixture comprising picrolonic acid (HPA) and benzo-15-crown-5 (B15C5) in chloroform has been used for the extraction of Ce(III), Eu(III) and Tm(III) as representatives of lanthanide(III) ions from pH 1-2 solutions having ionic strength of 0.1 mol. dm-3(K+/H+, Cl-). The...

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