Complex Energetic Perchlorates of Cobalt(III) Amminates,with Cyclopentamethylenetetrazole as Ligand

Energetic metal complexes, pentammine(cyclopentamethylenetetrazole)cobalt(III) perchlorate and tetraammine-bis(cyclopentamethylenetetrazole)cobalt(III) perchlorate, were obtained by reaction of aquapentaamminecobalt(III) and diaquatetraamminecobalt(III) ions with cyclopentamethylenetetrazole. Microwave heating was used, together with the conventional convective heating, for thermal activation of the process. The thermal decomposition of the compounds synthesized was studied. The explosive characteristics and toxicity of the metal complexes were determined.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 2, 2005, pp. 195–199.Original Russian Text Copyright © 2005 by Zhilin, Ilyushin, Tselinskii, Nikitina, Kozlov, Shugalei.     

Kinetics of the radiation chemical reactions of tervalent and quadrivalent actinides and lanthanides in carbonate solutions

The reactions of the ions of tervalent and quadrivalent actinides and lanthanides with hydrated electrons e_aq ^– and CO₃ ^– radicals in concentrated carbonate solutions have been studied by microsecond pulse radiolysis, using spectrophotometric recording of short-lived particles. It is shown that the rate of the reactions of e_aq ^– with carbonato complexes of Ce(IV), Pu(IV), and Np(IV) is controlled by diffusion. The carbonato complex of Eu(III) reacts with e_aq ^–appreciably more slowly. A linear relationship is obtained between the logarithm of the rate constant for the reactions of CO₃ ^– with the carbonato complexes of Am(III), Ce(III), and Pu(III) and the redox potential of the complexes. The rate of the reaction of CO₃ ^– with Np(III) in carbonate solutions is controlled by diffusion.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 28–32, January, 1990.     

Characterization of the adsorption state of carbonate ions at the Au(111) electrode surface using in situ IRAS

The spectro-electrochemical behavior of carbonate and bicarbonate ions at the Au(111) electrode surface was studied using the infrared reflection absorption spectroscopy (IRAS). An absorption band caused by the adsorbed carbonate ions was observed in the wavenumber region of 1425–1511 cm⁻¹ both in Na₂CO₃ and NaHCO₃ solutions. It was concluded that the adsorbed carbonate ions co-ordinate with the electrode surface in the unidentate state with their symmetry axis normal to the substrate. This orientation is retained in the whole potential region where carbonate ions adsorb on the electrode surface in contrast to the behavior of the carbonate ions adsorbed on the Pt(111) electrode surface.     

Solvent Extraction Separation of Germanium(IV) with N-<Emphasis Type="Italic">n</Emphasis>-Octylaniline As an Extractant

The extraction behavior of germanium(IV) from aqueous hydrochloric acid solution with N-n-octylaniline in xylene was investigated. Hydrochloric acid concentration higher than 9 M remained effective for quantitative extraction of germanium(IV). Phenylfluorone ion as a counter anion was used. More than 2% N-n-octylaniline provided quantitative extraction at 1 min equilibrium time and germanium(IV) was back extracted by 7 M ammonia. The method was free from the interference of a large number of metal ions and anions, except for Te(IV) and Sn(IV); this was avoided using the masking effect. Germanium(IV) was separated from associated elements in its binary mixture with Si(IV), Te(IV), Sb(III), Bi(III), Au(III), Cu(II), Zn(II), and its ternary mixture with Se(IV), Te(IV); Sb(III), Bi(III); and Au(III), Cu(II). The proposed method was applied to a synthetic sample containing associated metal ions. The results indicated that trace amounts of germanium(IV) could be separated effectively from higher amounts of other elements.__________From Zhurnal Analiticheskoi Khimii, Vol. 60, No. 5, 2005, pp. 463–467.Original English Text Copyright © 2005 by Sargar, Anuse.This article was submitted by the authors in English.     

The structures of the active intermediates in Catalyst-Enhanced Molten Salt Oxidation and a new method for the complete destruction of chemical warfare arsenicals

Catalyst-Enhanced Molten Salt Oxidation (CEMSO) is our improvement of the earlier process, Molten Salt Oxidation (MSO), originally employed for the destruction of hazardous materials by high temperature oxidation in a carbonate melt. MSO was abandoned because it was slow and only partially oxidized cotton, paper, and plastics. It was very efficient for many other chemicals and had oxidized the nerve gas sarin with >99.9999% efficiency. We came to realize that the concentration of the oxidizing species, superoxide and peroxide ions, produced from the oxygen entering the carbonate melt, could be increased and maintained by the addition of nitrate ions as catalyst. The structure and interatomic distances for the various possible adducts between nitrate and nitrite with oxygen and peroxide have been calculated for the first time by Density Functional Theory (DFT). Their calculated enthalpies, as a function of temperature, revealed which adducts can be formed in the carbonate melt. The Japanese still have large stocks of the chemical warfare arsenicals Clark I and Clark II awaiting a destruction procedure that ensures removal of all volatile As(III) compounds. We have established that As(V) salts are stable at high temperature and here discuss how CEMSO can efficiently achieve this for the Clark arsenicals.     

Automated Method for the Selective Determination of Gold by On-Line Solvent Extraction and Reversed Micellar-Mediated Luminol Chemiluminescence Detection

A new method based on the direct coupling of on-line solvent extraction with chemiluminescence (CL) of luminol in reverse micelles is proposed for the determination of gold(III) in a reverse-flow injection system. In the on-line process, gold(III) is extracted from aqueous hydrochloric acid solution with tri-n-octylphosphine oxide in chloroform, followed by separation through a microporous Teflon membrane. A reversed micellar system of cetyltrimethylammonium chloride-water (buffered with sodium carbonate)-6:5 (v/v) chloroform-cyclohexane was used as a medium for the CL reaction. Linear calibration for gold was established over the concentration range 10-5000 ng ml⁻¹ and the detection limit was 1 ng ml⁻¹. Much higher tolerable levels of potential interfering metal ions were achieved for the present on-line procedure. The present method was applied to the analysis of industrial samples of silver-based alloy.     

A new model for the rationalization of the thermal behavior of carbonated apatites

A new model for the location and distribution of carbonate ions in carbonated apatite was used to assign the IR spectra of A- and AB-carbonated apatites. The percentage of total carbonate as measured by the mass loss in the TGA of these compounds is in good agreement with the percentage obtained by combustion analysis. The decomposition of pure A-type carbonate appears at temperatures of 985–1123 °C, whereas the decomposition of AB-type carbonated apatites occurs in the range of 600–800 °C. This difference is attributed to changes in the environment of channel carbonate brought about by B-type substitution of carbonate for phosphate. In the presence of sodium ions, the channel is changed by substitution of sodium for calcium in order to accommodate the difference between the charge of the carbonate and phosphate ions. A thermodynamic cycle is introduced to rationalize the differences in decomposition temperatures of A- and B-type carbonate. Preferential loss of B-type carbonate upon heating to 600 °C also suggests the migration of B-type carbonate to A-sites.

     

Electrochemical Sensors Based on Stationary Electrodes and Immobilized DNA or Its Fragments and the Assessment of Their Analytical Potentials

Amperometric biosensors were developed on the basis of stationary mercury-film and glassy-carbon electrodes and DNA or its fragments, oligodeoxynucleotides (ODNs), immobilized in a nitrocellulose matrix. Taking into account the high affinity of Cu(II) and Fe(III) ions to denatured DNA ((19.1 ± 0.1) ×10⁵ and (1.4 ± 0.3) × 10⁵ L/mol, respectively), a procedure was proposed for the voltammetric determination of these ions in natural materials and blood serum at a level of n × 10⁻¹¹ M. This procedure involves analyte pre-concentration on a DNA-containing biosensor. An ODN-containing biosensor (DNA probe) was used in the study of DNA hybridization for the highly specific determination of its nucleotide sequence.__________Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 6, 2005, pp. 639–645.Original Russian Text Copyright © 2005 by Babkina, Palecek, Jelen, Fojta.Presented at the VI All-Russia Conference (with international participation) on Electrochemical Methods of Analysis (EMA-2004, Ufa, May 23–27, 2004).     

Characterization of europium(III) carbonate complexes in simulated groundwater by solvent extraction

The complex formation of Eu(III) by bicarbonate/carbonate ions has been studied at 0.1 M ionic strength and 25°C using synergistic solvent extraction system of 1-nitroso-2-naphthol and 1,10-phenanthroline in chloroform. Concentrations of bicarbonate (5·10^–3 to 1·10^–1 M) and carbonate (5·10^–4 to 1·10^–2 M) ions in the aqueous phase have been varied in the pH range of 8.0 to 9.1 to simulate ground and natural water compositions. Under these conditions, the following species have been identified: Eu(HCO₃)²⁺, Eu(HCO₃)₂ ⁺, Eu(CO₃)⁺ and Eu(CO₃)₂ ^–. Their conditional formation constants (log ) have been calculated as 4.77, 6.74, 6.92 and 10.42, respectively. These values suggest that the carbonate complexes of Eu(III) are highly stable.     

Application of 8-amino-N-(2-hydroxybenzylidene)naphthyl amine as a neutral ionophore in the construction of a lanthanum ion-selective sensor

In this work, a novel La(III) membrane sensor based on 8-amino-N-(2-hydroxybenzylidene)naphthylamine (AIP) is presented. This electrode reveals good selectivity for La³⁺ over a wide variety of lanthanides metal ions. Theoretical calculations and conductance study of AIP to lanthanum and some other metal ions were carried out and confirmed selectivity toward La(III) ions. The electrode comprises 7% AIP, 30% PVC, 61% NPOE and 2% KTpClPB. The sensor displays a linear dynamic range between 1.0 × 10⁻⁷ and 1.0 × 10⁻¹ M, with a nice Nernstian slope of 20.3 ± 0.3 mV per decade and a detection limit of 8.0 × 10⁻⁸ M. The potentiometric response is independent of pH in the range of 4.0-9.0. The proposed sensor posses the advantage of short response time, and especially, very good selectivity towards a large number of cations, such as Sm(III), Ce(III, Pr(III), Yb(III) and Hg(II), low detection limit and wide linear dynamic range in comparison with former ones. The electrode can be used for at least seven weeks without any considerable divergence in the potentials. It was used as an indicator electrode in the potentiometric titration of La(III) ions with EDTA. The sensor was applied to the determination of La(III) ions concentration in binary mixtures. It was also applied for the determination of fluoride ions in mouth wash preparations.     

Thermal Stability of Some Polynuclear Coordination Compounds in the Systems Ln(III)—Co(II)—Oxalate

This paper reports an investigation of the thermal stabilities of the class of coordination compounds containing lanthanide ions Ln(III) (Ln=La, Sm, Eu, Dy, Er), Co(II) ions and oxalate anions C₂O ₄ ^2– . The thermal decomposition steps were identified, and in some cases the values of the non-isothermal kinetic parameters were determined.This revised version was published online in November 2005 with corrections to the Cover Date.     

Calculation of the Magnetic Properties of Low-Symmetry Polynuclear Complexes. Exchange Interactions in the Hexanuclear Chromium(III) Pivalate

A theory that allows numerical calculations and interpretation of magnetic properties of low-symmetry polynuclear complexes containing a large number of orbitally non-degenerate transition metal ions is developed by the irreducible tensor operator method. The potential of the theory was illustrated using the chromium(III) complex, Cr₆O₂(OH)₂[O₂CC(CH₃)₃]₁₁ as an example.__________Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 7, 2005, pp. 518–522.Original Russian Text Copyright © 2005 by Rakitin, Smith.     

Effect of Zero-Field Splitting on the Magnetic Susceptibility of Binuclear Complexes of Iron(III)

The effect of zero-field splitting on the magnetic susceptibility of inuclear complexes formed by high-spin iron(III) ions was studied. An analytic expression describing the magnetic susceptibility of such systems is presented. It was shown that in dimers with weak magnetic exchange the experimental data only fit adequately if the effect of zero-field splitting (ZFS) is taken into account. The effect of ZFS on the accuracy of the values obtained for the exchange parameters with various D/J ratios is discussed. __________ Translated from Teoreticheskaya i Eksperimental'naya Khimiya, Vol. 41, No. 4, pp. 219–224, July–August, 2005.     

Membrane electrodes selective for hydrogen phosphate ions

The possibility of using plasticized polyvinyl chloride film membranes with dispersed electroactive substances (MgNH₄PO₄, BiPO₄, and CrPO₄) for developing electrodes selective for hydrogen phosphate ions has been investigated. It is shown that a chromium(III) phosphate-based electrode is characterized by the linearity range KT^-1-KT^-6 M of the hydrogen phosphate function with a slope of 26.5 mV/pc and a satisfactory selectivity in the presence of chloride, nitrate, sulfate, and hydrogen carbonate ions. Presented at the V All-Russian Conference with the Participation of CIS Countries on Electrochemical Methods of Analysis (EMA-99), Moscow, December 6–8, 1999.     

A cerium(III) selective polyvinyl chloride membrane sensor based on a Schiff base complex of N,N'-bis[2-(salicylideneamino)ethyl]ethane-1,2-diamine

A polyvinyl chloride (PVC) based membrane sensor for cerium ions was prepared by employing N,N′-bis[2-(salicylideneamino)ethyl]ethane-1,2-diamine as an ionophore, oleic acid (OA) as anion excluder and o-nitrophenyloctyl ether (o-NPOE) as plasticizer. The plasticized membrane sensor exhibits a Nernstian response for Ce(III) ions over a wide concentration range (1.41 × 10⁻⁷ to 1.0 × 10⁻² M) with a limit of detection as low as 8.91 × 10⁻⁸ M. It has a fast response time (<10 s) and can be used for 4 months. The sensor revealed a very good selectivity with respect to common alkali, alkaline earth and heavy metal ions. The response of the proposed sensor is independent of pH between 3.0 and 8.0. It was used as an indicator electrode in potentiometric titration of fluoride, carbonate and oxalate anions and determination of cerium in simulated mixtures.     

Propylene carbonate as a solvent for salting-out extraction and subsequent differential pulse polarography

Summary Selective and sensitive procedures are described for the direct differential pulse polarographic determination of antimony(III), indium(III) and cadmium(II) in propylene carbonate. This method was based on the salting-out extraction of their halide complexes into the solvent from acidic aqueous media. The extracted Sb(III), In(III) and Cd(II) complexes exhibit sharp differential pulse polarographic peaks at –0.21 V, –0.63 V and –0.72 V vs. SCE in salted-out propylene carbonate phases respectively. The lower limits of determination are 5.0g for Sb(III), 0.6g for In(III), and 0.2g for Cd(II) in 10 ml of the organic phase. A number of foreign ions are eliminated through both processes of solvent extraction and polarography using propylene carbonate.

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Propylencarbonat als Lösungsmittel für die Fällungs-Extraktion und die nachfolgende Differential-Puls-Polarographie

Zusammenfassung Selektive und empfindliche Verfahren für die direkte Bestimmung von Sb(III), In(III) und Cd(II) in Propylencarbonat mit Hilfe der Differential-Puls-Polarographie wurden beschrieben. Die vorliegende Methode beruht auf der Fällungs-Extraktion der Halogenid-Komplexe aus wäßrig-saurem Medium in das Lösungsmittel. Die extrahierten Komplexe des Sb(III), In(III) und Cd(II) ergeben scharfe Peaks bei –0,21 V, –0,63 V und –0,72 V gegen die Kalomelelektrode in den betreffenden Propylencarbonat-Phasen. Die unteren Grenzen der Bestimmungen liegen bei 5,0g Sb, 0,6g In bzw. 0,2g Cd in 10 ml organischer Phase. Eine Anzahl Fremdionen wird durch die beiden Prozesse der Extraktion und der Polarographie in Propylencarbonat ausgeschaltet.

     

Chemically-modified activated carbon with ethylenediamine for selective solid-phase extraction and preconcentration of metal ions

A new method that utilizes ethylenediamine-modified activated carbon (AC-EDA) as a solid-phase extractant has been developed for simultaneous preconcentration of trace Cr(III), Fe(III), Hg(II) and Pb(II) prior to the measurement by inductively coupled plasma optical emission spectrometry (ICP-OES). The new sorbent was prepared by oxidative surface modification. Experimental conditions for effective adsorption of trace levels of Cr(III), Fe(III), Hg(II) and Pb(II) were optimized with respect to different experimental parameters using batch and column procedures in detail. The optimum pH value for the separation of metal ions simultaneously on the new sorbent was 4.0. Complete elution of absorbed metal ions from the sorbent surface was carried out using 3.0 mL of 2% (%w/w) thiourea and 0.5 mol L⁻¹ HCl solution. Common coexisting ions did not interfere with the separation and determination of target metal ions. The maximum static adsorption capacity of the sorbent at optimum conditions was found to be 39.4, 28.9, 60.5 and 49.9 mg g⁻¹ for Cr(III), Fe(III), Hg(II) and Pb(II), respectively. The time for 94% adsorption of target metal ions was less than 2 min. The detection limits of the method was found to be 0.28, 0.22, 0.09 and 0.17 ng mL⁻¹ for Cr(III), Fe(III), Hg(II) and Pb(II), respectively. The precision (R.S.D.) of the method was lower 4.0% (n = 8). The prepared sorbent as solid-phase extractant was successfully applied for the preconcentration of trace Cr(III), Fe(III), Hg(II) and Pb(II) in natural and certified samples with satisfactory results.     

Gas-stirred solvent extraction with propylene carbonate for separation and direct polarographic determination of thallium (III)

Gas-stirred propylene carbonate (PC) extraction can be performed by bubbling nitrogen without loss of volume. This extraction technique has proved to be highly useful for the separation and subsequent direct polarographic estimation of Tl(III) in the recovered PC phase. Tl(III) can be determined by differential-pulse polarography over the concentration range of 0.4 10 g ml^–1 without any interferences due to most metal ions such as Pb(II), Bi(III), Cu(II), Sb(III) and As(III). This proposed technique would be possible to use as a simple extraction step prior to the final estimation by instrumental method of analysis such as atomic absorption spectrometry or spectrophtometry.     

Chemiluminescence determination of iron(II) and titanium(III) by flow injection analysis based on reactions with and without luminol

Titanium(III) and iron(II) are shown to stimulate luminol chemiluminescence in the absence of added oxidant. Down to 10^?9 M titanium can be determined. Both metal ions also produce chemiluminescence when injected into 0.1 M carbonate buffer (pH 10.4), allowing >10^?6 M of each to be determined. The intensities are greater when the solutions have been deoxygenated by a stream of nitrogen, and when rhodamine B is used as a sensitizer.     

Eco-friendly green synthesis of functionalized mesoporous silica nanospheres for the determination of Al(III) ions in multiple samples of different kinds of water

The current work proposed a new green procedure that is not sophisticated to recognize and determine the Al(III) ions in multiple water samples. The suggested method was conducted based upon the direct immobilization of aurintricarboxylic acid reagent into the mesoporous silica nanospheres to shape a unique and novel solid sensor. Al(III)-ATA red-complex has been formed at pH 4.0 and spectrophotometrically measured at 525 nm. Moreover, the complexation was reversible, and the ATA sensor retained his functionality even after six-time reuse/cycles using EDTA as eluent. Univariate and multivariate (partial least squares 1, PLS-1) calibration techniques were utilized for calculating the figures of merit for the determination of the Al(III) ions. The obtained calibration curve was linear from 2.0 to 70 ppb Al(III) ions concentration. The developed method has a detection limit of 3.5 ppb. In addition, the ATA sensor showed high adsorption capacity value (118.53 mg/g) which gives it a great advantage to be applicable as nanocollector for trapping Al(III) ions. The novel ATA sensor showed high degree of selectivity, sensitivity, reproducibility, and stability. The current study explores the effectiveness of the ATA sensor for the first time to produce a green solid sensor to determine the trace amount of Al(III) in diverse water types; tap, mineral, river, well, and sea water.