Separation of cerium and europium by extraction with tributyl phosphate and di(2-ethylhexyl)phosphoric acid in n-alkane from nitrate solutions

The following extraction systems have been studied: (Ce³⁺+Eu³⁺) (NO₃)-(EDTA, DCTA, DTPA)/TBP in n-alkane and (Ce³⁺+Eu³⁺)(NO₃)/DEHPA in n-alkane at concentration ratios as follows: [Ce³⁺]=trace –1 mol·dm^–3, [Eu³⁺]=trace –0.1 mol·dm^–3. [TBP]=(0.183–1.83) mol·dm^–3, [DEHPA]=(5·10^–3–0.1) mol·dm^–3, [(H, Na)NO₃]=(0.1–6) mol·dm^–3, [Eu³⁺]: [EDTA, DCTA, DTPA]=11–110. The initial concentration of Eu³⁺ in aqueous phase in the extraction system containing a mixture of Ce³⁺ and Eu³⁺ was trace, 1% and 10% compared with the Ce³⁺ concentration. The distribution of the elements between the phases was observed radiometrically using¹⁴¹Ce,¹⁵²Eu and¹⁵⁴Eu. The results are documented by the distribution ratios D_Ce, D_Eu and separation factor =D_Eu/D_Ce as functions of variable parameters of the systems.     

Ion-exchange selectivity and chromatographic separation of trivalent metals on titanium antimonate

Summary The ion exchange selectivity of trivalent metal ions has been determined on titanium antimonate cation exchanger prepared by coprecipitation of antimony to titanium at different mole ratios. The selectivity sequence Al³⁺<Cr³⁺<Ga³⁺<In³⁺<Fe³⁺ was found for trivalent metal ions at an initial concentration of 10^–4 mol dm^–3 in nitric acid media. A high separation factor ^Ga/Al = Kd^Ga/Kd^Al, 4.8×10³, was observed for the Ga³⁺–Al³⁺ pair on titanium antimonate with an antimony to titanium ratio of 0.34. The effective separation of Ga³⁺ and In³⁺ from Al³⁺ was achieved using a 3 cm×0.5 cm i.d. column containing titanium antimonate with an antimony to titanium ratio of 0.34.     

Comparative studies on the ion exchange behaviour of UO2(II), Ce(III) and Am(III) with Chelex-100 from thiocyanate media

The distribution of UO ₂ ²⁺ , Ce³⁺ and Am³⁺ between Chelex-100 and 0.2 and 5.0M ammonium thiocyanate solutions of different hydrogen ion concentrations has been investigated. The results obtained are compared with parallel experimental results using the anion exchanger Dowex-1×4 and the cation excharger Dowex-50×8. It is found that Chelex-100 can act as anion exchanger at pH<2 and as cation and chelate exchanger at higher pH. A main feature of the distribution results of UO ₂ ²⁺ , Am³⁺ and Ce³⁺ with Chelex-100 is the very high distribution coefficient for the three cations at pH higher than 3.5 from aqueous solutions containing 0.2 or 5.0M ammonium thiocyanate.     

Extraction of tri- and tetravalent actinides with dihexyl N,N-diethylcarbamoylmethyl phosphonate (DHDECMP) and TBP from nitric acid solutions

Extraction of trivalent (Pu³⁺, Am³⁺, actinides and Eu³⁺, a representative of lanthanides) and tetravalent (Np⁴⁺ and Pu⁴⁺) actinides has been studied with dihexyl N,N-di-ethylcarbamoylmethyl phosphonate (DHDECMP) in combination with TBP in benzene from 2M nitric acid. The stoichiometries of the species extracted were found to be M(NO₃)₃·(3–n) TBP·n DHDECMP (for trivalent ions) and M(NO₃)₄·(2–n) TBP·n DHDECMP (for tetravalent ions) by the slope ratio method. The extraction constants evaluated (from the distribution data) indicate that for tetravalent ions (with solvation number two) the extraction constant increases when TBP (Kh=0.17) molecules are successively replaced by more basic DHDECMP (Kh=0.34) molecules. However, for trivalent ions (with solvation number three) when TBP molecules are totally replaced by DHDECMP molecules stereochemical factors appear and instead of increase, a substantial decrease in extraction constants is observed for Eu³⁺ and Am³⁺, a lesser decrease being observed for Pu³⁺ (larger ion).     

Warm white light from Y4MgSi3O13:Bi, Eu nanophosphor for white light-emitting diodes

Y₄MgSi₃O₁₃:Bi³⁺, Eu³⁺ nanophosphors have been prepared by a facile sol–gel method. The products have been characterized by X-ray diffraction, field-emission scanning electron microscopy and fluorescence measurements. The results show that the nanophosphors are of single phase hexagonal Y₄MgSi₃O₁₃ with size-distribution of 50–90 nm in diameter. White-light emission has been obtained from Bi³⁺ and Eu³⁺ co-doped Y₄MgSi₃O₁₃ nanophosphors upon excitation of 350 nm ultraviolet light. It is noted that Bi³⁺ ions can occupy two different Y³⁺ sites and generate different emissions from the ³p₁ → ¹s₀ transition. Warm white light has been obtained from Y₄MgSi₃O₁₃:Bi³⁺, Eu³⁺ nanophosphors according to Commission International de I’Eclairage (CIE) chromaticity coordinates and color temperature (T_c) with appropriately adjusted contents of Bi³⁺ and Eu³⁺. The results indicate that Y₄MgSi₃O₁₃:0.08Bi³⁺, 0.04Eu³⁺ (x = 0.31, y = 0.31, T_c = 6907 K) are potential nanophosphors for white light-emitting diodes (LEDs) applications.     

Nitrogen isotope exchange between nitric oxide and nitric acid

The rate of nitrogen isotope exchange between NO and HNO₃ has been measured as a function of nitric acid concentration of 1.5–4M·1^–1. The exchange rate law is shown to beR=k[HNO₃]²[N₂O₃] and the measured activation energy isE=67.78kJ ·M^–1 (16.2 kcal·M^–1). It is concluded that N₂O₃ participates in¹⁵N/¹⁴N exchange between NO and HNO₃ at nitric acid concentrations higher than 1.5M·1^–1.     

Synthesis and photoluminescence properties of the high-brightness Eu-doped M2Gd4(MoO4)7 (M=Li, Na) red phosphors

A series of red-emitting phosphors Eu³⁺-doped M₂Gd₄(MoO₄)₇ (M=Li, Na) have been successfully synthesized at 850 °C by solid state reaction. The excitation spectra of the two phosphors reveal two strong excitation bands at 396 nm and 466 nm, respectively, which match well with the two popular emissions from near-UV and blue light-emitting diode chips. The intensity of the emission from ⁵D₀ to ⁷F₂ of M₂(Gd_1−xEu_x)₄(MoO₄)₇ phosphors with the optimal compositions of x=0.85 for Li or x=0.70 for Na is about five times higher than that of Y₂O₃:Eu³⁺. The quantum efficiencies of the entitled phosphors excited under 396 nm and 466 nm are also investigated and compared with commercial phosphors Sr₂Si₅N₈:Eu²⁺ and Y₃A₅O₁₂:Ce³⁺. The experimental results indicate that the Eu³⁺-doped M₂Gd₄(MoO₄)₇ (M=Li, Na) phosphors are promising red-emitting phosphors pumped by near-UV and blue light.     

Selective cation exchange isolation of radioactive mercury from cobalt,scandium and europium

Distribution of Hg²⁺, Co²⁺, Sc³⁺ and Eu³⁺ between the cation exchanger Dowex-50X8, [H⁺] (100–200 mesh), and 1M HNO₃ solution containing different benzylamine (BA) concentrations has been studied. The distribution coefficient, D, for Co²⁺, Sc³⁺ and Eu³⁺ is very small and does not vary seriously with the BA concentration. It is also found that Hg²⁺ is highly taken by the resin from the media studied. In this respect, D increases with increasing BA concentration to reach a maximum at 0.5% BA in 1M HNO₃. This behaviour is explained by the exchange of molecular species between the cation exchanger and the aqueous phase. Based on the results, a radiochemical separation procedure for the selective isolation of Hg²⁺ from Co²⁺, Sc³⁺ and Eu³⁺ has been developed. The radiochemical purity is not less than 99.8% and the chemical yield more than 95% for the separated²⁰³Hg.     

Synthesis and characterization of tin(IV) antimonate and study of its ion-exchange equilibria

Tin(IV) antimonate with different Sb/Sn molar ratios has been prepared. The characterization of the product materials was carried out using X-ray diffraction pattern, themal analysis and infrared spectra. The saturation capacities of sodium and cesium were found to increase with Sb/Sn molar ratios. TheK _d values on thermal treatment of tin(IV) antimonate, as a cation exchanger, have been measured for some heavy metal ions in the temperature range of 50–400 °C. The maximum adsorption of 10^–4M of the metal ions studied was obtained at 400 °C. The selectivity sequence was Eu³⁺>Co²⁺>Sr²⁺>Cs⁺ for the sample heated up to 400 °C. No adsorption was observed on the sample heated at 700 °C because of the formation of SnO₂ and Sb₆O₁₃.     

Vacuum Ultraviolet Excited Photoluminescence Properties of Y2O2S：Eu^3＋,Bi^3＋ Phosphor

As an Hg-free lamp using phosphor, the Bi^3＋ and EH^3＋ co-doped Y2O2S phosphors were prepared and their luminescence properties under vacuum ultraviolet（VUV） excitation were investigated. The VUV photoluminescent intensity of Y2O2S：Eu^3＋ was weak, however, considerably stronger red emission at 626 nm with good color purity was observed in Y2O2S：Eu^3＋,Bi^3＋ systems. Investigation on the photoluminescence reveals that the strong VUV luminescence of Y2O2S：Eu^3＋,Bi^3＋ at 147 nm is mainly because the Bi^3＋ acts as a medium and effectively performs the energy transfer process： Y^3＋-O^2-→Bi^3＋→Eu^3＋, while the intense emission band at 172 nm is attributed to the absorption of the characteristic ^1So-^1P1 transition of Bi^3＋ and the direct energy transfer from Bi^3＋ to Eu^3＋. The Y2O2S：Eu^3＋,Bi^3＋ shows excellent VUV optical properties compared with the commercial （Y,Gd）BO3：Eu^3＋. Thus, the Y2O2S：Eu^3＋,Bi^3＋ can be a potential red VUV-excited candidate applied in Hg-free lamps for backlight of liquid crystal display.     

Radioluminescence of Europium(III) in POCl3–SnCl4–235UO2+ 2–Eu3+, and D2O–235UO2+ 2–Eu3+ Solutions

Results of studying the spectral and luminescent properties of Eu³⁺ ions upon homogeneous excitation of POCl₃–SnCl₄–^-UO²⁺ ₂–Eu³⁺ and D₂O–²³⁵UO²⁺ ₂–Eu³⁺ solutions by -particles are presented. It was found that the radioluminescence intensity of Eu³⁺ ions in both solvents increases proportionally to the energy input by -particles. The yield of radioluminescence photons from europium ions in the POCl₃–SnCl₄–UO²⁺ ₂–Eu³⁺ solutions is more than nine times as high as that in D₂O–UO²⁺ ₂–Eu³⁺. The radiation-chemical yields of excited ⁵ D ₀ states of Eu³⁺ ions are 0.74 ± 0.07 and 0.18 ± 0.02 ions/100 eV in POCl₃–SnCl₄–UO²⁺ ₂–Eu³⁺ and D₂O–UO²⁺ ₂–Eu³⁺ solutions, respectively.     

Bismuthiol II as an analytical reagent

Summary The estimation of bismuth by the reagent Bismuthiol II is studied critically. The effect of acidity, reagent concentration and interfering ions are given in detail. The maximum acidity that may be tolerated for the complete precipitation of bismuth is 0.3 N in nitric acid, 0.5 N in hydrochloric acid and 1N in sulphuric acid. Higher acidity than 0.1 N decomposes the reagent present in excess. In 0.1 N nitric acid bismuth has been separated from a number of ions like Al³⁺, Cr³⁺, Th⁴⁺, rare earths, Zr⁴⁺, Ti⁴⁺, UO₂ ²⁺, Be²⁺, Mn²⁺, Co²⁺, Ni²⁺, Mg, alkalis and alkaline earths, SO₄ ^2–, Cl^–, C₂O₄ ^2–- and from Fe²⁺ and Ce³⁺ in 0.1 N hydrochloric acid. In presence of a citrate or a tartrate it can be separated from As³⁺, Ce⁴⁺, MoO₄ ^2–- and WO₄ ^2–-at p_H 1.5 to 2.5. When Hg²⁺, Pb²⁺, Pd²⁺, Cd²⁺, Cu²⁺, Ag⁺ and Tl⁺ are present they are first precipitated by the reagent at p_H 6 to 8 in presence of a citrate or a tratrate and the bismuth is estimated gravimetrically in the acidified filtrate. Ions as F^– and PO₄ ^3– that form insoluble compounds with bismuth, Sb³⁺ and Sn²⁺ that form less soluble compounds with the reagent and Fe³⁺, VO₃ ^–, CrO₄ ^2–, AsO₄ ^3– that act as oxidising agents, interfere.     

Study of Complex Formation between Kryptofix 21 with La<Superscript>3+</Superscript>, Y<Superscript>3+</Superscript> and Ce<Superscript>3+</Superscript> Cations in Some Binary Mixed Non-Aqueous Solvents Using the Conductometric Method

The complexation reactions between La³⁺, Y³⁺ and Ce³⁺ cations with the macrocyclic ligand, kryptofix 21, were studied in methanol-acetonitrile (MeOH-AN) and methanol-methylacetate (MeOHMeOAc) binary mixed solvent solutions at different temperatures using the conductometric method. The conductance data show that in most solvent systems, the kryptofix 21 forms a 1: 1 [M: L] complex with La³⁺, Y³⁺ and Ce³⁺ metal cations, but in the case of Y³⁺ cation in pure methylacetate, in addition of formation of a 1: 1 [ML] complex, 1: 2 [ML₂] and 1: 3 [ML₃] complexes are formed in solution. In the case of Ce³⁺cation, a 1: 1 [ML] and also a 1: 2 [ML₂] complexes are formed in this solvent system at all studied temperatures. The electrical conductance data in acetonitrile, show that a 1: 1 [ML] and also a 1: 2 [ML₂] complexes are formed between the ligand and La³⁺ and Ce³⁺ metal cations at different temperatures. The stability constants of the 1: 1 [ML] complexes were determined using the conductometric data and a computer program, GENPLOT. A non-monotonic relationship was observed between log_{K f} of the 1: 1 complexes with the composition of the binary solvent solutions which was discussed in term of solvent-solvent interactions and also preferential solvation of the metal cations and the ligand in solutions. The selectivity order of the ligand for the metal cations in MeOH–AN and MeOH–MeOAc binary solvent solutions, at 25°C was found to be: Y³⁺ > La³⁺ > Ce³⁺ and La³⁺ > Y³⁺ > Ce³⁺, respectively. The values of the standard thermodynamic quantities (ΔH _c ^° and ΔS _c ^° ) for formation of the 1: 1 complexes were obtained from temperature dependence of the stability constans of the complexes and the results show that the thermodynamics of the complexation reactions between kryptofix 21 and La³⁺, Y³⁺ and Ce³⁺ cations, is affected by the nature and composition of the mixed solvents systems.     

Luminescence Quenching between Ce and Eu in LAB3O6

The Ce³⁺ and Eu³⁺ ions in LaB₃O₆ quench each other's luminescence. However, Ce³⁺ quenches Eu³⁺ more effectively than Eu³⁺ quenches Ce³⁺. The critical distances for this quenching are about 15 and 6 Å respectively.     

The synergistic effect of cobalt-dicarbollide anions on the extraction of M lanthanide cations by Calix[4]arenes: a molecular dynamics study at the water–‘oil’ interface

We report molecular dynamics studies on the effect of CCD^– (chlorinated cobalt-dicarbollide) anions on the Eu³⁺ lanthanide cation extraction by a calix[4]arene-CMPO ligand L, focusing on the water–‘oil’ interface, where ‘oil’ is modelled by chloroform. The free L ligand and its EuL³⁺ complex are found to adsorb and to concentrate at the interface, but are too hydrophilic to be extracted. Addition of CCD^– anions in diluted conditions (either covalent linked to L or as separated CCD^– H₃O⁺ ions) also leads to adsorption of these species at the interface. However, at high concentrations, CCD^– anions saturate the interface and promote the extraction of EuL³⁺ to the oil phase. Another important feature concerns the uncomplexed Eu(CCD)₃ salt: accumulation of CCD^– anions at the interface creates a negative potential which attracts the hydrated Eu³⁺ ions, therefore facilitating their complexation by interfacial ligands. These features allow us to better understand the synergistic effect of lipophilic anions in the assisted liquid-liquid extraction of trivalent M³⁺ lanthanide or actinide cations. To cite this article: B. Coupez, G. Wipf, C. R. Chimie 7 (2004).

Résumé

Synergie due aux anions dicarbollides lors de l’extraction d’ions lanthanides M³⁺ par des calix[4]arènes : simulations de dynamique moléculaire à l’interface eau–« huile ». Nous étudions par simulations de dynamique moléculaire l’effet de synergie dû aux anions CCD^– (cobalt-dicarbollides) lors de l’extraction de Eu³⁺ par un calix [4]arène L, en se focalisant sur l’interface eau–« huile », l’huile étant modélisée par du chloroforme. On montre que le ligand L et son complexe EuL³⁺ s’adsorbent à l’interface, mais sont trop hydrophiles pour être extraits. L’addition d’anions CCD^– (qu’ils soient sous la forme d’ions CCD^– H₃O⁺ séparés ou greffés de façon covalente au calixarène) conduit aussi à l’adsorption de ces espèces à l’interface. Cependant, aux plus fortes concentrations, les anions CCD^– saturent l’interface et induisent l’extraction du complexe EuL³⁺ vers l’huile. Un autre résultat remarquable concerne les sels Eu(CCD)₃ : l’accumulation des anions CCD^– à l’interface y crée un potentiel négatif, ce qui attire les cations Eu³⁺ et facilite ainsi leur complexation par des ligands à l’interface. Ces résultats permettent de mieux comprendre l’effet de synergie dû aux anions CCD^– lors de l’extraction d’ions lanthanides ou actinides M³⁺ et, d’une manière générale, ce qui se passe à l’interface entre l’eau et des liquides non miscibles. Pour citer cet article : B. Coupez, G. Wipf, C. R. Chimie 7 (2004).     

Bismuthiol II as an analytical reagent

Summary The reagent Bismuthiol II completely precipitates palladium at a maximum acidity of 0.3 N in nitric acid, 0.5 N in hydrochloric acid or 1 N in sulphuric acid and also at a maximum p_H of about 8.0. The palladium complex Pd (C₈H₅N₂S₃)₂ is stable even up to a temperature of about 250° C. From a mineral acid solution palladium can be estimated in presence of ions of Fe²⁺, Al, Cr, Th, Ce³⁺, Zr, Ti⁴⁺, UO₂ ²⁺, Be, Mn, Co, Ni, Mg, P0₄ ^3–, AsO₄ ^3–, rare earths, alkalis, alkaline earths, Ce⁴⁺, WO₄ ^2– and MoO₄ ^2– that are not ordinarily precipitated by the reagent. At a p_H of 4.75 to 8.2, EDTA, Na-salt, keeps in solution, besides the above ions, the ions of Tl+, Cu²⁺, Pb, Bi³⁺, As³⁺, Sb³⁺, Zn, Cd, Fe³⁺, CrO₄ ^2–, AsO₃ ^3– and VO₃ ^–. Tartrate, however, at a p_H 6.2–8, keeps all the ions including Sn⁴⁺ in solution except of course Tl⁺, Cu²⁺, Pb and Cd. Separation from Ce⁴⁺, WO₄ ^2–, MoO₄ ^2– and AsO₄ ^3– at a low p_H require the presence of tartrate. Ag⁺, Hg²⁺ and also Pb may be complexed with potassium iodide at a p_H 6–8. Tl⁺ and Ag⁺ may also be separated in presence of cyanide in an acetate buffer when palladium remains in solution and from which it may be re-precipitated by acidification.Part II see Z. analyt. Chem. 154, 413 (1957).     

Y2O3:Eu (5 mol%) with Ag nanoparticles prepared by citrate precursor

Y₂O₃:Eu³⁺ (5 mol% Eu³⁺) and Y₂O₃:Eu³⁺ (5 mol% Eu³⁺) containing 1 mol% of Ag nanoparticles were prepared by heat treatment of a viscous resin obtained via citrate precursor. TEM and EDS analyses showed that Y₂O₃:Eu³⁺ (5 mol% Eu³⁺) is formed by nanoparticles with an average size of 12 nm, which increases to 30 nm when Ag is present because the effect of metal induced crystallization occurs. Ag nanoparticles with a size of 9 nm dispersed in Y₂O₃:Eu³⁺ (5 mol% Eu³⁺) were obtained and the surface plasmon effect on Ag nanoparticles was observed. The emission around 612 nm assigned to the Eu³⁺ (⁵D₀→⁷F₂) transition enhanced when the Ag nanoparticles were present in the Y₂O₃:Eu³⁺ luminescent material.     

Chemie der Seltenerdmetalle, 19. Mitt.: Dissoziation des Ce(III)-succinats im sauren Gebiet

Zusammenfassung Die Dissoziation von Ce₂ Suc ₃·3 H₂O^** in Perchlorsäure-Lösungen wurde verfolgt und die Dissoziationskonstanten der Succinationen: (CeSuc)⁺ und (CeSuc ₂)^– unter Benützung einer Löslichkeitsmethode in 1m-NH₄ClO₄-Lösung bei 25°C bestimmt. Die Löslichkeitsprodukte von Ce₂ Suc ₃: [Ce³⁺]²[Suc ^2–]³, [CeSuc ⁺]²[Suc ^2–], [CeSuc ⁺][CeSuc ₂ ^–] wurden bestimmt.

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The dissociation of Ce₂ Suc ₃·3H₂O in perchloric acid solutions was investigated. The dissociation constants of the succinate ions (CeSuc)⁺ and (CeSuc ₂)^– were determined inM-NH₄ClO₄ at 25° using a solubility method and the solubility products of Ce₂ Suc ₃, i. e. [Ce³⁺]²[Suc ^2–]³, [CeSuc ⁺]²[Suc ^2–], [CeSuc ⁺][CeSuc ₂ ^–] measured.

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18. Mitt.:R. Pastorek, Lanthantartrate im neutralen und alkal. Bereich. Mh. Chem.99, 676 (1968).     

Zur spektralphotometrischen Bestimmung von Uran(VI) in Gegenwart einiger Fremdelemente mit Hilfe von Halogenderivaten der Essigs?ure

Zusammenfassung Die Pufferlösungen CH₂ClCOOH + CH₂ClCOONa (I), CH₂BrCOOH + CH₂BrCOONa (II) und CH₂JCOOH + CH₂JCOONa (III) wurden als Reagentien für die Uranbestimmung vorgeschlagen.Das Beersche Gesetz wird für den Konzentrationsbereich von 0,11903 bis 2,85684 mg/ml Uran mit 0,1 m Reagenslösungen befolgt. Y³⁺, Ce³⁺ und Th⁴⁺ sind ohne Einfluß.Für den Konzentrationsbereich von 0,11903–3,80912 mg/ml Uran werden 1 m Reagenslösungen angewendet. Bei Verwendung von (I) oder (II) stören Y³⁺, Ce³⁺ und Th⁴⁺ nicht. Wird (III) benutzt, muß man zur Vermeidung der Störung durch Thorium, Uran mit Essigester extrahieren.

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Summary The buffer solutions CH₂ClCOOH + CH₂ClCOONa (I), CH₂BrCOOH + CH₂BrCOONa (II) and CH₂ICOOH + CH₂ICOONa (III) are shown to provide new reagents for the spectrophotometric determination of uranium.The method can be used for the direct determination of 0.11903 to 2.85684 mg of uranium with. 0.1 M reagents, when Y³⁺ or Ce³⁺ or Th⁴⁺ are present. With 1 M concentrations, 0.11903 to 3.80912 mg of uranium can be directly determined in presence of Y³⁺ and Ce³⁺; with (I) or (II), thorium has no effect on the absorbance, too; with. (III) uranium must be previously extracted into ethyl acetate.

     

<Emphasis Type="Italic">N,N</Emphasis>’-Bis(acylvinylated) diaza-18-crown-6 ether as a lanthanide-selective macrocyclic complex-forming agent

Nucleophilic substitution in β-chlorovinyl phenyl ketone with diaza-18-crown-6 ether resulting in displacement of the chlorine atom afforded N,N’-bis(3-oxo-3-phenylpropen-1-yl)-1,10-diaza-18-crown-6 ether. The ability of the latter to form complexes with a number of metal cations was studied. However, the complex formation occurs only with the rare-earth cations Ln³⁺ and Th⁴⁺. This fact was demonstrated by UV and ¹H NMR spectroscopy of solutions, confirmed by isolations of glassy phases of composition L₃M₂(NO₃)₆ · nH₂O (M = La, Y, n ≈ 4–7), and supported by IR spectra of these phases in KBr pellets. The formation of complexes with La³⁺ and Y³⁺ leads to an increase in fluorescence intensity of the ligand. The stability constants of the 1 : 1 complexes in methanol were evaluated by spectrophotometry. These constants increase with decreasing ionic radius of the cation.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 156–160, January, 2005.