17455-13-9Relevant articles and documents
Effects of complexation with 18-crown-6 on the hypernucleofugality of phenyl-λ3-iodanyl groups. Synthesis of vinyl- λ3-iodane·18-crown-6 complex
Ochiai, Masahito,Suefuji, Takashi,Miyamoto, Kazunori,Shiro, Motoo
, p. 2893 - 2896 (2005)
(Chemical Equation Presented) 4-tert-Butyl-1-cyclohexenyl(phenyl) (tetrafluoroborato)-λ3-iodane forms a discrete supramolecular complex by the reaction with 18-crown-6. Solvolysis of the cyclohexenyl- λ3-iodane in the presence of 18-crown-6 indicates that the complexation with 18-crown-6 tends to decrease the leaving group ability of hypervalent phenyl-λ3-iodanyl groups.
N,N'-BIS(SUBSTITUTED)-4,13-DIAZA-18-CROWN-6 DERIVATIVES HAVING PI-DONOR-GROUP-SIDEARMS: CORRELATION OF THERMODINAMICS AND SOLID STATE STRUCTURES
Arnold, Kristin A.,Viscariello, Anthony M.,Kim, MinSook,Gandour, Richard D.,Fronczek, Frank R.,Gokel, George W.
, p. 3025 - 3028 (1988)
Solution thermodynamic data and solid state structure information are used to show that a series of N,N'-bis(substituted)-4,13-diaza-18-crown-6 (BiBLE) derivatives which lack oxygen or nitrogen donor groups in the sidearms do not utilize the sidearms for binding but show considerable variation in their binding constants.
A Facile Synthesis of Hexa- and Octaethylene Glycols
Nakatsuji, Yohji,Kameda, Nobuko,Okahara, Mitsuo
, p. 280 - 281 (1987)
One-pot syntheses of hexa- and octaethylene glycol are achieved by the reaction of tri- or tetraethylene glycol with tosyl chloride in the presence of an appropriate base followed by a Williamson-type condensation reaction.
STUDIES OF CROWN ETHER COMPLEXES; ARYLDIAZONIUM ION COMPLEXES
Krane, Jostein,Skjetne, Tore
, p. 1775 - 1778 (1980)
DNMR studies show that for complexation of aryldiazonium salts 21-crown-7 is the preferred host.
The Complexation of Alkaline Cations by Crown Ethers and Cryptand in Acetone
Buschmann, H.-J.,Cleve, E.,Schollmeyer, E.
, p. 569 - 578 (1994)
Stability constants and thermodynamic values for the complex formation of alkali ions by crown ethers, diaza crown ethers and cryptands have been measured by means of potentiometric and calorimetric titrations in acetone as solvent.The interactions between the ligands and solvent molecules play an important role for the complex formation.Cryptands form the most stable complexes with alkali ions if inclusion complexes are formed.Even in the case that the salts are not completely dissociated in acetone the presence of ion pairs does not influence the calculated values of the stability constants.
Facile and rapid synthesis of some crown ethers under microwave irradiation
Ziafati, Ahmad,Sabzevari, Omolbanin,Heravi, Majid M.
, p. 803 - 807 (2006)
A series of crown ethers were synthesized from the reaction of 1,8-dichloro-3,6-dioxaoctane with the appropriate hydroxy compound under microwave irradiation in short times and high yields. Copyright Taylor & Francis Group, LLC.
Lithium-7 Nuclear Magnetic Resonance and Calorimetric Study of Lithium Crown Complexes in Various Solvents
Smetana, Alfred J.,Popov, Alexander I.
, p. 183 - 196 (1980)
Lithium-7 NMR studies have been carried out on lithium ion complexes with crown ethers 12C4, 15C5, and 18C6 in water and in several nonaqueous solvents.In all cases the exchange between the free and complexed lithium ion was fast on the NMR time scale, and a single, population average, resonance was observed.Both 1:1 and 2:1 (sandwich) complexes were observed between lithium ion and 12C4 in nitromethane solution.The stability of the complexes varied very significantly with the solvent.With the exception of pyridine, the stability varies inversely with the Gutmann donor numbers of the solvent.In general, the stability order of the complexes was found to be 15C5*Li+ > 12C4*Li+ >18C6*Li+.Calorimetric studies on thse complexes show that, in most cases, the complex are both enthalpy and entropy stabilized.
Properties and applications of cryptand-22 surfactant for ion transport and ion extraction
Hwang, Wen-Yu,Shih, Jeng-Shong
, p. 1215 - 1222 (2000)
A non-ionic cryptand-22 surfactant consisting of a macrocyclic cryptand-22 polar head and a long paraffinic chain (C10H21-Cryptand-22) was synthesized and characterized. The critical micellar concentration (CMC) of the cryptand surfactant in ROH/H2O mixed solvent was determined by the pyrene fluorescence probe method. In general, the cmc of the cryptand surfactant increased upon decreasing the polarity of the surfactant solution. The cryptand surfactant also can behave as a pseudo cationic surfactant by protonation of cryptand-22 or complexation with metal ions. Effects of protonation and metal ions on the cmc of the cryptand surfactant were investigated. A preliminary application of the cryptand surfactant as an ion-transport carrier for metal ions, e.g., Li+, Na+, K+ and Sr2+, through an organic liquid-membrane was studied. The transport ability of the cryptand surfactant for these metal ions was in the order: K+ ≥ Na+ > Li+ > Sr2+. A comparison of the ion-transport ability of the cryptand surfactant with other macrocyclic polyethers, e.g., dibenzo-18-crown-6, 18-crown-6 and benzo-15-crown-5, was studied and discussed. Among these macrocyclic polyethers, the cryptand surfactant was the best ion-transport carrier for Na+, Li+ and Sr2+ ions. Furthermore, a foam extraction system using the cryptand surfactant to extract the cupric ion was also investigated.
TEMPLATE EFFECTS. 7. LARGE UNSUBSTITUTED CROWN ETHERS FROM POLYETHYLENE GLYCOLS: FORMATION, ANALYSIS, AND PURIFICATION
Vitali, Chiara Antonini,Masci, Bernardo
, p. 2201 - 2212 (1989)
Through the reaction of polyethylene glycols with tosyl chloride and heterogeneous KOH in dioxane not only coronands from crown-4 to crown-8 can be obtained but also larger homologues.A systematic investigation has shown that: i) crown-9 and crown-10 can be formed from nona- and deca-ethylene glycol, respectively, and isolated in pure form; ii) the whole series of polyethylene glycols from tri- to deca-ethylene glycol yields not only the corresponding crown ethers but also higher cyclooligomers that can be analyzed up to about crown-20 by glc: in particular crown-12 and crown-16 were obtained from tetraethylene glycol and purified by column chromatography on cellulose; iii) the reaction, as applied to commercial mixtures of polyethylene glycols (from PEG 200 to PEG 1000), gives fairly high yields of crown ethers also in the region of large ring sizes.The contribution of the template effect of K(+) ion and the cyclooligomerization reactions for the various ring sizes are discussed.
Reactivity with electrophiles of imido groups supported on trinuclear titanium systems
Caballo, Jorge,Gonzalez-Moreiras, Mariano,Mena, Miguel,Perez-Redondo, Adrian,Yelamos, Carlos
, p. 11519 - 11529 (2013)
Several trinuclear titanium complexes bearing amido μ-NHR, imido μ-NR, and nitrido μn-N ligands have been prepared by reaction of [{Ti(η5-C5Me5)(μ-NH)} 3(μ3-N)] (1) with 1 equiv of electrophilic reagents ROTf (R = H, Me, SiMe3; OTf = OSO2CF3). Treatment of 1 with triflic acid or methyl triflate in toluene at room temperature affords the precipitation of compounds [Ti3(η 5-C5Me5)3(μ3-N) (μ-NH)2(μ-NH2)(OTf)] (2) or [Ti3(η 5-C5Me5)3(μ3-N) (μ-NH)(μ-NH2)(μ-NMe)(OTf)] (3). Complexes 2 and 3 exhibit a fluxional behavior in solution consisting of proton exchange between μ-NH2 and μ-NH groups, assisted by the triflato ligand, as could be inferred from a dynamic NMR spectroscopy study. Monitoring by NMR spectroscopy the reaction course of 1 with MeOTf allows the characterization of the methylamido intermediate [Ti3(η5-C 5Me5)3(μ3-N)(μ-NH) 2(μ-NHMe)(OTf)] (4), which readily rearranges to give 3 by a proton migration from the NHMe amido group to the NH imido ligands. The treatment of 1 with 1 equiv of Me3SiOTf produces the stable ionic complex [Ti3(η5-C5Me5) 3(μ3-N)(μ-NH)2(μ-NHSiMe 3)][OTf] (5) with a disposition of the nitrogen ligands similar to that of 4. Complex 5 reacts with 1 equiv of [K{N(SiMe3)2}] at room temperature to give [Ti3(η5-C 5Me5)3(μ3-N)(μ-N)(μ-NH) (μ-NHSiMe3)] (6), which at 85 C rearranges to the trimethylsilylimido derivative [Ti3(η5-C 5Me5)3(μ3-N)(μ-NH) 2(μ-NSiMe3)] (7). Treatment of 7 with [K{N(SiMe 3)2}] affords the potassium derivative [K{(μ3-N)(μ3-NH)(μ3-NSiMe 3)Ti3(η5-C5Me5) 3(μ3-N)}] (8), which upon addition of 18-crown-6 leads to the ion pair [K(18-crown-6)][Ti3(η5-C 5Me5)3(μ3-N)(μ-N)(μ-NH) (μ-NSiMe3)] (9). The X-ray crystal structures of 2, 5, 6, and 8 have been determined.
