Showing papers on "15-Crown-5 published in 2002"
TL;DR: An efficient recognition of K+ by 15-crown-5 functionalized gold nanoparticles in aqueous matrix containing physiologically important cations, such as Li+, Cs+, NH4+, Mg2+, Ca2+, and excess amount of Na+.
Abstract: Reported here is an efficient recognition of K+ by 15-crown-5 functionalized gold nanoparticles in aqueous matrix containing physiologically important cations, such as Li+, Cs+, NH4+, Mg2+, Ca2+, and excess amount of Na+. Upon exposure to K+, the colloidal solution changes from red to blue, in response to surface plasmon absorption of dispersed and aggregated nanoparticles. The concentration ranges of K+ detected in this study are 0.099−0.48 mM and 7.6 μM−0.14 mM, when concentrations of colloidal gold are 54.9 and 7.1 nM, respectively. Recognition of K+ and formation of the aggregates are proposed via a sandwich complex of 2:1 between 15-crown-5 moiety and K+. Also discussed is the possibility of a preorganized structure of 15-crown-5 at the water−organic interface for the efficient complexation with K+.
259 citations
TL;DR: An 18-crown-6 holographic film was shown to be able to quantitate K+ concentrations over the physiologically relevant range and shows promise for developing simple, low-cost K+ sensors for medical applications.
Abstract: Holographic sensors for Na+ and K+ have been fabricated from crown ethers incorporated into polymeric hydrogels. The methacrylate esters of a homologous series of hydroxyether crown ethers were synthesized and copolymerized with hydroxyethyl methacrylate and the cross-linker ethylene dimethacrylate (3 mol %) to form stable hydrogel films (∼10 μm thick) containing covalently bound (0−97 mol %) 12-crown-4, 15-crown-5, and 18-crown-6 pendant functionalities. The films were transformed into silver-based volume holograms using a diffusion method coupled with a holographic recording using a frequency-doubled Nd:YAG laser. The resulting holographic reflection spectrum was used to characterize the shrinkage and swelling behavior of the holograms as a function of polymer composition and the nature and concentration of alkali, alkaline earth, and NH4+ ions in the test media. Optimized film compositions containing 50 mol % crown ether showed substantial responses (≤200 nm) within 30 s at ion concentrations of ≤30 mM...
91 citations
TL;DR: The molecular structure, spectroscopy and mass spectrometry of the following compounds are described in this article : [Na(dme)Cp]∞ (polymeric zigzag chain), [K(Dme)0.5CpMe], [Na[dme]Cp], [K[Dme]0.1Cp ], [DmeCp]-Me, [DMECp].
Abstract: The molecular structure, spectroscopy and mass spectrometry of the following compounds are described: [Na(dme)Cp]∞ (polymeric zigzag chain), [K(dme)0.5Cp]∞ (2-dimensional polymeric zigzag), [Na(15-crown-5)Cp] (monomeric), [Na(18-crown-6)CpMe] (monomeric) and [K(15-crown-5)2][Cp] {K(15-crown-5)2 cation/naked cyclopentadienide anion}. The syntheses of the related species [Na(dme)CpMe], [K(dme)0.5CpMe], [Na(15-crown-5)CpMe], [Na(18-crown-6)Cp] and [K(15-crown-5)2][CpMe] are reported. The choice of coordination modes displayed by those species structurally characterised is discussed, particularly in terms of steric and electrostatic considerations.
48 citations
TL;DR: Several studies have been carried out on chemical exchange of lithium isotopes as discussed by the authors, in which relatively large isotope separation coefficients have been obtained by using crown ethers or cryptands, and they have been used to avoid the use of mercury.
Abstract: Naturally occurring lithium consists of two stable isotopes, 6Li (7.5 at%) and7Li (92.5 at%). The lithium isotopes have different nuclear properties of thermal neutron absorption. Due to the large cross section for the thermal neutron, enriched light isotope6Li is used as a tritium breeding material in D-T burning fusion reactors. Enriched heavy isotope 7Li (in the form of LiOH) has been used as a pH controlling material for PWR (pressurized water reactor) nuclear fission reactors. Enriched isotopes of lithium have been produced by lithium amalgam electrolysis. To avoid the use of mercury, alternative processes have been studied for lithium isotope separation. Chemical exchange methods have been considered as useful isotope separation techniques. Several studies have been carried out on chemical exchange of lithium isotopes. 1–4) In these studies, relatively large isotope separation coefficients ( ε) have been obtained by using crown ethers or cryptands. 3–9)
45 citations
TL;DR: In this paper, a Schiff base of gossypol with 2-(aminomethyl)-15-crown-5 [GSCB] was shown to be capable of complexation of monovalent cations.
Abstract: A new Schiff base of gossypol with 2-(aminomethyl)-15-crown-5 [GSCB] was shown to be capable of complexation of monovalent cations. This process of complex formation was studied by electrospray ionization (ESI) mass spectrometry, 1H NMR and FT-IR spectroscopy, as well as by PM5 semiempirical method. It was found that the gossypol Schiff base can form 1 ∶ 1 and 1 ∶ 2 complexes with monovalent cations. With H+, Li+ or Na+ cations the Schiff base preferentially forms 1 ∶ 2 complexes. In the complex with protons they are localised on the N atoms of the Schiff base and the molecule exists in the imine–imine tautomeric form. The 1 ∶ 2 complexes of the Schiff base with Li+ and Na+ cations occur only in the enamine–enamine tautomeric form and the cations are coordinated only by the oxygen atoms of the crowns. The complexes of the Schiff base with K+, Rb+ or Cs+ cations are of 1 ∶ 1 and 1 ∶ 2 type with the oxygen atoms of the crowns, as well as O1H and O1′H groups coordinating the cations. The structures of the complexes are calculated by PM5 semiempirical method and disscussed.
38 citations
TL;DR: The synthetic system presented here suggests that the Mg-O bond may be considered a constituent design element in the rational preparation of complexes to bind and recognize biotin, and illustrates the importance of second-shell interactions in the biocoordination chemistry of Mg2+.
Abstract: The interaction between biotin and the macrocyclic magnesium complex Mg(15-crown-5)(Otf)2 (15-crown-5 is 1,4,7,10,13-pentaoxacyclopentadecane, Otf- is trifluoromethanesulfonate anion) in solution was studied as a model for metal−biotin interactions that may be important in its speciation and function. Shifts in the solution IR spectrum establish that the interaction is dominated by ligation between the carbonyl oxygen of the ureido ring of biotin and the Mg2+ cation. However, comparative binding studies using NMR spectroscopy and conductivity reveal a substantial enthalpic contribution to binding that arises from interactions between the ureido −NH moiety and the macrocyclic ring. This is interpreted in terms of a weak-to-moderate hydrogen bond formed between the −NH group and an oxygen from the crown, which is simultaneously coordinated to Mg2+. This hypothesis is reinforced by quantitative examination of the binding of N-methylated derivatives of 2-imidazolidone, which shows that N,N’-dimethylation decr...
22 citations
TL;DR: In this paper, single crystal X-ray diffraction analyses were carried out for all three compounds 1a, 1b, 1c, and show that monomeric units were present in the solid state with the organic aromatic anion coordinated to the sodium cation via the five-membered ring.
21 citations
TL;DR: 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 and raised the cation selectivity for Na(+) over K(+), but the donating substituents reduced the cations selectivity.
Abstract: 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.
21 citations
TL;DR: In this article, Li et al. showed that the crown ethers exhibit a bridging coordination mode via one crown oxygen from each crown to form a (KO)2 four-membered ring; the amide adopts a terminal chelating mode.
16 citations
TL;DR: In this paper, the properties of dipyrido-15-crown-5 ligands have been characterized and the crystal structure of [Zn(SC6H4CH3-p)2(dppzc)] has been determined.
13 citations
TL;DR: In this paper, the enthalpies of 15-crown-5 ether with Na+ were measured at 25°C and the standard Gibbs energies of complex formation as a function of the normalized Lewis acidity parameters and enthalpy of solvation were analyzed.
Abstract: Enthalpies of solution of 15-crown-5 ether in the acetonitrile–water–sodium iodide system have been measured at 25°C. The equilibrium constants of complex formation of 15C5 with sodium iodide have been determined by molar conductance at various mole ratios 15C5 to sodium iodide in mixtures of water with acetonitrile at 25°C. The thermodynamic functions for complexation of the crown ether with Na+ were calculated. From the result, the standard Gibbs energies of complex formation as a function of the normalized Lewis acidity parameters ENT and enthalpy of solvation of 15C5 in the mixtures of water with acetonitrile have been analyzed. The enthalpies of transfer of the 15C5 complex with sodium iodide from pure acetonitrile to the mixtures studied were calculated and discussed.
Journal Article•
TL;DR: Several reactions occur during the initiation of 2-(9-carbazolyl)ethyl glycidyl ether polymerization by K−, K+ (15-crown-5)2.
TL;DR: In this paper, the effects of the benzo group on the extraction-selectively and -ability of benzo-15-crown-5 (B15C5) for alkali metal ions, the constants of the overall extraction (Kex), thedistribution for various diluents having low dielectric constants (KD,MLA), and the aqueousion-pair formation (KMLA) were quantitatively elucidated.
Abstract: To quantitatively elucidate the effects of the benzo group on the extraction-selectively and -ability of benzo-15-crown-5 (B15C5)for alkali metal ions, the constants of the overall extraction (Kex), thedistribution for various diluents having low dielectric constants (KD,MLA), and the aqueousion-pair formation (KMLA) of B15C5-alkali metal (Li, Na, K) picrate 1:1:1 complexes (MLA) weredetermined at 25 °C The partition constants of B15C5were also measured at 25 °C The log KMLA values for Li+, Na+, and K+ are -032 ± 022, 266 ± 019, and 071 ± 047, respectively In going from 15-crown-5 (15C5) to B15C5, the benzo group considerably decreasesthe KMLA value for the same alkali metal ion The distributionbehavior of B15C5 and its 1:1:1 complexes with the alkali metal picrates closely obeys regularsolution theory, omitting chloroform Molar volumes and solubility parameters of B15C5and the 1:1:1 complexes were determined For every diluent, the Kex valuefor B15C5 increases in the order Li+ < K+ < Na+ KD,MLA makes anunfavorable contribution to the Na+ extraction-selectivity of B15C5 because of the smallest molar volume of the Na(B15C5)A complex The Na+ extraction-selectivity of B15C5 is determined completely by much the highest KNa(B15C5)A valueThe extraction-ability and -selectivity of B15C5 for the alkali metal picrates are compared with those of 15C5on the basis of the underlying equilibrium constants
TL;DR: A fluoroionophore, 1-(anthryl)-2-(benzo-15-crown-5)ethene, was synthesized and showed remarkably high cation-induced fluorescence enhancement for magnesium ion.
Abstract: A fluoroionophore, 1-(anthryl)-2-(benzo-15-crown-5)ethene, was synthesized. This crown ether derivative showed remarkably high cation-induced fluorescence enhancement for magnesium ion.
TL;DR: In this article, the kind of substituent in alkyl glycidyl ethers affects the course of their reaction with K−, K+(15-crown-5)2.
TL;DR: The first terphenyl-based sodium phosphanide, namely DmpP(H)Na (1) (Dmp=2,6-dimesitylphenyl) as well as the X-ray crystal structure determination of a crown ether adduct of the sodium salt were reported as mentioned in this paper.
TL;DR: In this article, the stability of crown ether complexes with alkali metal ion in the crown cavity was measured in water at 25°C and transfer activity coefficients of B15C5 and 15C5 complexes were determined.
Abstract: Stability constants (KML) of 1 : 1 benzo-15-crown-5 (B15C5) complexes with alkali metal ions were conductometrically measured in water at 25°C. Transfer activity coefficients of B15C5 and 15-crown-5 (15C5) from water to polar nonaqueous solvents were determined at 25°C. By using these data and the literature values, transfer activity coefficients of the B15C5 and 15C5 complexes with alkali metal ions from water to the polar nonaqueous solvents were calculated to study the solute-solvent interaction of the crown ether complexes. The stability of the B15C5 complex is lower in water than in any other nonaqueous solvent. The KML value for B15C5 is always smaller than the corresponding K ML value for 15C5. The interaction of the B15C5 or the 15C5 complex with the solvents depends on the alkali metal ion in the crown cavity. All the B15C5 and 15C5 complexes undergo hydrophobic hydration, which is particularly stronger for the B15C5 complexes with Na+ and K+. The unexpectedly lowest stability of the B15C5- or th...
TL;DR: In this paper, the crystal structure and luminescent properties of bis(benzo-15-crown-5)europium(II) diperchlorate were reported.
Abstract: The present paper reports the crystal structure and luminescent properties of bis(benzo-15-crown-5)europium(II) diperchlorate. The structure is composed of complex bis(benzo-15-crown-5)europium(II) cations and perchlorate anions. The complex cation is centrosymmetric, and the metal ion is surrounded by 10 oxygen atoms of two ligand molecules. The compound shows very bright luminescence at 23450 cm−1. The emission parameters (wavelength and the average lifetime of the excited state) are compared to those previously reported for the analogous complex in methanol solutions. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)
Journal Article•
TL;DR: Ruthenium(II) tetra-15crown-5phthalocyaninate (R 4 Pc 2 - )Ru 2 + (CO)(CH30H) was synthesized and spectroscopically characterized for the first time as mentioned in this paper.
Abstract: Ruthenium(II) tetra-15-crown-5-phthalocyaninate (R 4 Pc 2 - )Ru 2 + (CO)(CH30H) (R 4 Pc 2 - = [4,5,4',5',4",5",4"',5"'-tetrakis(1,4,7,10,13-pentaoxatridecamethylene)phthalocyaninate ion]) was synthesized and spectroscopicallycharacterized for the first time. In this complex, the ruthenium atom axially coordinates CO and CH 3 OH molecules as extra ligands. The composition and structure of this compound have been established by means of electronic absorption spectroscopy, 1 H NMR, MALDI-TOF mass spectrometry, and IR spectroscopy.
TL;DR: In this paper, the presence of B15C5 leads to a great synergistic effect for the extraction of strontium and an antagonistic effect of yttrium, and the separation factor a(Sr/Y) in the system with B15c5 presents the same order of magnitude as that for 15C5.
Abstract: Extraction of strontium and yttrium by the nitrobenzene solution of H+-form of heptachloro-bis-1,2-dicarbollylcobaltate (H+B–) in the presence of benzo-15-crown-5 (B15C5, L) has been investigated. The presence of B15C5 leads to a great synergistic effect for the extraction of strontium and an antagonistic effect for the extraction of yttrium. The extraction constants of Sr2+ complexes of B15C5 were determined. The separation factor a(Sr/Y) in the system with B15C5 presents the same order of magnitude as that for 15C5.
TL;DR: A crown-containing N-thiophosphorylthioamide has been synthesised by a reaction between diisopropyl thiophophosphate chloride and (4-amidothiocarbonyl-1,2-benzo)-15-crown-5, and its chelate complex with nickel(II) has been obtained as mentioned in this paper.
Abstract: Three kinds of positional isomers of the C-pivot type of double-armed 15-crown-5 ethers (cis and trans isomers for each positional isomer) bearing two 8-quinolyloxy moieties as part of the electron-donating sidearms were prepared, and their complexation properties were evaluated by measuring the stability constant in THF, the extractability, and passive transport velocity. Cis isomers were found to be much better host compounds toward alkali metal cations than trans isomers possibly because of the potential cooperative coordination of two electron-donating sidearms. All trans isomers showed almost the same stability constants toward Na+ and K+. On the other hand, in the case of cis isomers, the difference in the position of the two sidearms on the crown ring was found to remarkably affect the complexation properties toward alkali metal cations.
TL;DR: In this article, a 6FDA (4,4′-hexafluoro isopropylidene diphthalic anhydride) based copolyimide has been synthesized containing the diamines DABA (3,5-diamino benzoic acid) and a 15-crown-5diamine to separate propylene/propane mixtures.
TL;DR: In this article, it was shown that the functionality of protonated polymers is equal to about 1.2 as a result of propagation occurring on dipotassium glycoxides.
TL;DR: In this paper, it was shown that potassium and sodium simultaneously present in aqueous solutions can be determined by photometry with the use of tetra-15-crown-5-phthalocyaninatocobalt.
Abstract: It is shown that potassium and sodium simultaneously present in aqueous solutions can be determined by photometry with the use of tetra-15-crown-5-phthalocyaninatocobalt.
TL;DR: In this paper, the transfer of sodium and potassium ions facilitated by dibenzo-15-crown-5 (DB15C5) has been studied at the micro-water/1,2-dichloroethane (water/DCE) interface supported at the tip of a micropipette.
Abstract: The transfer of sodium and potassium ions facilitated by dibenzo-15-crown-5 (DB15C5) has been studied at the micro-water/1,2-dichloroethane (water/DCE) interface supported at the tip of a micropipette. Cyclic voltammetric measurements were performed in two limiting conditions: the bulk concentration of Na+ or K+ in the aqueous phase is much higher than that of DB15C5 in the organic phase (DB15C5 diffusion controlled process) and the reverse condition (metal ion diffusion controlled process). The mechanisms of the facilitated Na+ transfer by DB15C5 are both transfer by interfacial complexation (TIC) with 1:1 stoichiometry under these two conditions, and the corresponding association constants were determined at log β1 = 8.97 ±0.05 or log β1 = 8.63 ±0.03. However, the transfers of K+ facilitated by DB15C5 show different behavior. In the former case it is a TIC process and its stoichiometry is 1:2, whereas in the latter case two peaks during the forward scan were observed, the first of which was confirmed as the formation of K+(DB15C5)2 at the interface by a TIC mechanism, while the second one may be another TIC process with 1:1 stoichiometry in the more positive potential. The relevant association constants calculated for the complexed ion, K+(DB15C5)2, in the organic phase in two cases, logβ2, are 13.64 ±0.03 and 11.34 ±0.24, respectively.
TL;DR: A mixed ligand lanthanum complex H-bonded with a crown ether benzo-15-crown-5 (B15C5) was synthesized and characterized by elemental analysis, infrared spectrum, and X-ray crystal structure analysis as discussed by the authors.
Abstract: A mixed ligand lanthanum complex H-bonded with a crown ether benzo-15-crown-5 (B15C5), [La(NO3)3(H2O)2phen]B15C5 (phen = phenanthroline), was synthesized and characterized by elemental analysis, infrared spectrum, and X-ray crystal structure analysis. The crystals of the title compound are monoclinic, P21, with a = 18.879(6) A, b = 20.110(5) A, c = 19.358(4) A, V = 6623.4 A3, β = 115.68(3)°, Z = 8, Dcalc = 1.623 g/cm3. In this complex, two nitrogen atoms from phen and eight oxygen atoms, six from NO3− and two from H2O, coordinate to La(III), forming a 10-coordination structural unit. The two H2O molecules are located in opposite directions of the unit, each H2O is H-bonded with two O atoms of the B15C5, and each B15C5 molecule is H-bonded with two H2O molecules on opposite sides, thus an infinite supramolecular chain forms. The title compound has a layered structure, and in each unit cell there exists one 3D channel.