Thermodynamics of substituted rhodanine II: Binary complexes of Th(IV), UO2(II), Ce(III), and La(III) with 3-benzamidorhodanine and its derivatives

Summary Th(IV), UO₂(II), Ce(III) and La(III) chelates with 3-benzamidorhodanine and its derivatives have been investigated potentiometrically in 0.1M KCl and 20% (v/v) ethanol-water medium. The stability of the formed complexes increases in the order Th(IV)>UO₂(II)>Ce(III)>La(III). For the same metal ion, the stability of the chelates is found to increase with decreasing temperature, ionic strength, dielectric constant of the medium and by increasing the electron repelling property of the substituent. The thermodynamic parameters (G, H and S) for complexation are evaluated and discussed. The formation of the complexes has been found to be spontaneous, exothermic and entropically favourable.

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Thermodynamik von substituiertem Rhodanin II: Binäre Komplexe von Th(IV), UO₂(II), Ce(III) und La(III) mit 3-Benzamidorhodanin und seinen Derivaten

Zusammenfassung Th(IV)-, UO₂(II)-, Ce(III)- und La(III)-Chelate mit 3-Benzamidorhodanin und seinen Derivaten wurden in 0.1M KCl und 20% (/) Ethanol-Wasser potentiometrisch untersucht. Die Stabilität der gebildeten Komplexe steigt in der Reihenfolge Th(IV)>UO₂(II)>Ce(III)>La(III). Für ein- und dasselbe Metallion steigt die Stabilität der Chelate mit sinkender Temperatur, Ionenstärke und Dielektrizitätskonstante des Mediums und mit steigender Elektronenabstoßungsfähigkeit des Substituenten. Die thermodynamischen Parameter (G, H und S) für die Komplexbildungsreaktion werden bestimmt und diskutiert. Die Bildung der Komplexe erweist sich als spontan, exotherm und entropisch begünstigt.

     

Liquid-liquid extraction and separation studies of uranium(vi)

Summary Separation of uranium(VI) from iron(III), molybdenum(VI), vanadium (V), bismuth(III), zirconium(IV) and thorium(IV) is achieved by liquid-liquid extraction with 4-methyl-3-pentene-2-one (mesityl oxide; MeO) from sodium salicylate media (0.1M, pH 6.0). The extracted species is UO₂(HO·C₆H₄COO)₂·2MeO. A procedure for separating 50g of uranium from mg amounts of the other metals is described.

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Flüssig-flüssig-Extraktion und Trennung von Uran(VI)

Zusammenfassung Die Trennung des U(VI) von Fe(III), Mo(VI), V(V), Bi(III), Zr(IV) und Th(IV) läßt sich durch Flüssig-flüssig-Extraktion mit 4-Methyl-3-penten-2-on] (Mesityloxid, MeO) aus 0,1M Natriumsalicylat bei pH 6,0 durchführen. Die extrahierte Verbindung ist UO₂(HO·C₆H₄COO)2·2MeO. Ein Verfahren zur Abtrennung von 50g Uran von Milligrammengen der anderen Metalle wurde beschrieben.

     

Spectrophotometric determination of copper(II) using oximidobenzotetronic acid

Summary Oximidobenzotetronic acid (OBTA) is proposed as a sensitive spectrophotometric reagent for the estimation of 0.5–3.0 ppm of copper(II) at 427 nm in 50% dioxan at p_H 5.3–7.5. For the estimation of 2 ppm Cu(II), 1.3 ppm Ni(II), 1.3 ppm Co(II), 3.2 ppm Fe(II), 10.3 ppm Fe(III), 9.7 ppm Ce(IV), 300 ppm acetate, 160 ppm oxalate, 95 ppm tartrate, 50 ppm citrate, as well as Zn(II), Cd(II), Hg(II)) Pb(II), Mn(II), As(III) as well as (V), Th(IV), Be(II), Ce(III), La(III), V(V) and Mo(VI), even when present in large quantities, do not interfere. The interference due to 25 ppm Bi(III), 20 ppm Sb(III), 20 ppm Sn(II), 25 ppm Sn(IV) and 30 ppm W(VI) can be removed by the addition of 95 ppm tartrate ions.

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Zusammenfassung Oximidobenzotetronsäure wurde als empfindliches Reagens zur spektrophotometrischen Bestimmung von 0,5 bis 3,0 ppm Kupfer(II) bei 427 nm in 50%iger Dioxanlösung bei p_H 5,3 bis 7,5 vorgeschlagen. Die Anwesenheit von 1,3 ppm Ni(II), 1,3 ppm Co(II), 3,2 ppm Fe(II), 10,3 ppm Fe(III), 9,7 ppm Ce(IV), 300 ppm Acetat, 160 ppm Oxalat, 95 ppm Tartrat, 50 ppm Citrat sowie die Anwesenheit auch großer Mengen Zn(II), Cd(II), Hg(II), Pb(II), Mn(II), As(III) bzw. (V), Th(IV), Be(II), Ce(III), La(III), V(V) und Mo(VI) stören die Bestimmung von 2 ppm Cu(II) nicht. Der störende Einfluß von 25 ppm Bi(III), 20 ppm Sb(III), 20 ppm Sn(II), 25 ppm Sn(IV) und 30 ppm W(VI) kann durch Zusatz von 95 ppm Tartrat beseitigt werden.

     

Mono- and Bi-nuclear metal complexes of arylidene-anthranilic acidSchiff bases

Arylidene-anthranilic acidSchiff base complexes with Th(IV), UO₂(II), La(III), Ce(III), and Zr(IV) have been isolated and studied by several techniques, e.g. elemental analysis, electronic and IR spectra and conductance measurements. It is concluded that the salicylideneanthranilic acidL ₃ is coordinated to the metal ion as bivalent tridentate ONO ligand (L ^–2) while the other ligands behave as monovalent bidentate ON ligands. Furthermore, the molecular structure effect of these compounds on their tendency towards complex formation was investigated and discussed. The possibility that the Cu(II) complex ofL ₃ can act as bidentate ligand, coordinating through itscis-oxygen atoms to form binuclear metal complexes was studied.

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Ein- und zweikernige Metall-Komplexe von Aryliden-Anthranilsäure-Schiff-Basen

Zusammenfassung Es wurden Aryliden-Anthranilsäure-Schiff-Basen mit Th(IV), UO₂(II), La(III), Ce(III) und Zr(IV) isoliert und mittels Elementaranalysen, Elektronen-und IR-Spektroskopie und Leitfähigkeitsmessungen untersucht. Es wird aus den Untersuchungen geschlossen, daß Salicylidenanthranilsäure (L ₃) als bivalenter dreizähniger ONO-Ligand (L ^–2) an das Metallion koordiniert, währenddessen die anderen Liganden als monovalente zweizähnige Liganden agieren. Außerdem wurden Struktureffekte dieser Verbindungen in bezug auf ihre Komplexbildungstendenz untersucht. Die Möglichkeit, daß der Cu(II)-Komplex vonL ₃ über die Koordination mit dencis-Sauerstoff-Atomen und unter Bildung eines zweikernigen Metallkomplexes als zweizähniger Ligand agieren kann, wurde untersucht.

     

Extraction and separation of bismuth(III) from steel and bismuth-base alloys

Summary Separation of bismuth(III) from iron(III), molybdenum(VI), vanadium(V), chromium(VI), titanium(IV), antimony(III), lead(II), beryllium(II), uranium(VI), hafnium(IV), indium(III) and zirconium (IV) is achieved by solvent extraction with high molecular weight amines from sodium succinate solution adjusted to suitable pH. Bismuth(III) is stripped from the organic phase and determined spectrophotometrically. The method is shown to be applicable to bismuth alloys.

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Extraktion und Trennung von Wismut(III) aus Stahl und wismuthältigen Legierungen

Zusammenfassung Wismut(III) läßt sich von Fe(III), Mo(VI), V(V), Cr(VI), Ti(IV), Sb(III), Pb(II), Be(II), U(VI), Hf(IV), In(III) und Zr(IV) durch Extraktion mit hochmolekularen Aminen aus Natriumsuccinat bei geeignetem pH trennen. Bi(III) wird dann von der organischen Phase getrennt und spektralphotometrisch bestimmt. Das Verfahren eignet sich für Wismutlegierungen.

     

Separation and micro-identification of metallic ions by ring oven technique. I

Summary Attempts to separate Hg(I), Pb(II), Ag(I), Hg(II), Bi(III), Cu(II), Cd(II), As(III), Sb(III) and Sn(II) in ternary, quaternary and quinary mixtures by the Weisz ring oven technique have been made, using oxalate as complexing agent and aqueous ethanol as solvent. It is found, in general, that addition of oxalate as complexing agent enables separations to be carried out which do not occur in the uncomplexed solutions. The effect of adding varying concentrations of the complexing agent to the solutions has been studied. The sequences of separation in ternary, quaternary and quinary mixtures with varying concentrations of the complexing agent have been described.

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Zusammenfassung Es wurde versucht, Hg(I), Pb(II), Ag(I), Hg(II), Bi(III), Cu(II), As(III), Sb(III) und Sn(II) in Drei-, Vier- und Fünfstoffgemischen unter Verwendung von Oxalat als Komplexbildner und wäßrigem Äthanol als Lösungsmittel nach der Ringofentechnik vonWeisz zu trennen. Im allgemeinen ermöglicht die Komplexierung mit Oxalat Trennungen, die sonst nicht durchführbar sind. Die Einwirkung verschiedener Konzentrationen des Komplexbildners auf die Probelösungen wurde geprüft. Die Reihenfolge der Trennung aus den angeführten Mischungen bei verschiedener Oxalatkonzentration wird angegeben.

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Résumé On a essayé de réaliser la séparation de Hg-I, Pb-II, Ag-I, Hg-II, Bi-III, Cu-II, Cd-II, As-III, Sb-III et Sn-II dans des mélanges ternaires, quaternaires et quinquénaires, au moyen de la technique du four annulaire deWeisz, en utilisant des oxalates comme agents complexants et l'éthanol aqueux comme solvant. On a trouvé que, généralement, l'addition d'oxalates comme agents complexants oblige à effectuer des séparations qui ne se rencontrent pas dans les solutions non complexées. On a étudié l'effet de l'addition de concentrations variables de l'agent complexant aux solutions. On a décrit les étapes de la séparation dans les mélanges ternaires, quaternaires et quinquénaires pour des concentrations variables de l'agent complexant.

     

Oximidobenzotetronic acid as a reagent for the separation and gravimetric determination of palladium and cobalt

Oximidobenzotetronic acid is recommended for the separation and gravimetric determination of palladium and cobalt An ethanolic solution of the reagent quantitatively precipitates palladium(II) from solutions which are 0.75 N in acid up to pH 5.1, the complex is weighed as Pd(C₉H₅NO₄)₂. Cobalt(II) can be determined in the filtrate after the precipitation of palladium. With 0.5 N acid solutions, no interference was found from Pt(IV), Ir(IV), Rh(III), Ru(III), Os(IV), Au(III), Ag(I), Cu(II), Fe(III), Ni(II), Hg(II). Pb(II), Bi(III), Cd(II), As(V), Se(VI), Te(IV), Mo(VI), Sb(III), Al(III), Cr(III), Zn(II), Ti(IV), Zr(IV). acetate, oxalate, citrate, tartrate, phosphate and fluoride.     

The spectrophotometric determination of vanadium after extraction as vanadium(III) ferronate by tribenzylamine

Vanadium(III) obtained by dithionite reduction of vanadium(V) can be extracted as its ferron complex with tribenzylamine in chloroform from 0.05 M sulphuric acid. Vanadium (0–5 μg ml^-1) is determined spectrophotometrically at 430 nm with a sensitivity of 0.0028 μg V cm^-2. Al(III), Co(II), Ni(II), Fe(II, III), Hg(II), Si(IV), Be(II), Mg(II), Ca(II), Sr(II), Ba(II), Cr(VI, III), W(VI), Zn(II), U(VI), Mn(II). Pb(II), Cu(II), Cd(II) and Th(IV) do not interfere; only Mo(VI), Ti(IV), Zr(IV). Bi(V) and Sn(II) interfere. A single determination takes only 7 min. The extracted complex is V^III (R-3H.TBA)₃ where R = C₉H₄O₄NSI. The method is satisfactory for the determination of vanadium in steels, alum and other samples without preliminary separations.     

The ion chromatographic separation of high valence metal cations using a neutral polystyrene resin dynamically modified with dipicolinic acid

A neutral polystyrene resin column, dynamically loaded with dipicolinic acid at a concentration of 0.1 mM in 1 M potassium nitrate eluent, was investigated for the separation characteristics of a number of high valence metal cations over the pH range 0-3. The metal species studied were Th(IV), U(VI), Zr(IV), Hf(IV), Ti(IV), Sn(IV), V(IV) and V(V), Fe(III) and Bi(III), of which Ti(IV), Sn(IV), V(IV) and Fe(III) did not show any retention. For the remaining metal ions, significant retention was obtained with good peak shapes, except for Th(IV), which moved only slightly from the solvent front with some tailing. The retention order at pH 0.3 was Th(IV) < V(V) < Bi(III) < U(VI) < Hf(IV) < Zr(IV). A notable feature of this separation system was the high selectivity shown for uranium, zirconium and hafnium, the last two being nearly resolved in 15 min on the relatively short 10 cm column.     

Complexes derived from some biologically active ligands

Complexes derived from ampicillin (L1) and amoxicillin (L2) with (Mg(II), Ca(II), Zn(II), Cu(II), Ni(II), Co(II), Ce(III), Nd(III), UO₂(VI), Th(IV)) were prepared and characterized by elemental analysis, electrical conductivity measurements, magnetic susceptibility, IR, UV/Vis, and thermogravimetry. The formed complexes can be formulated as (ML(H₂O)₃(NO₃) _n ) except for Ce(III) which gave (CeL(H₂O)₃(Cl)₂). The ¹H NMR spectra of the Zn(II) complexes are compared to spectra of the ligands. The shift (δ) gave information about the chelating center of the ligands. The ligands and the synthesized complexes, derived from some alkali earth and transition metal ions, were tested as antibacterial reagents. The formed complexes had enhanced activity.     

Syntheses,spectroscopic, and magnetic properties of polystyrene-anchored coordination compounds of tridentate ONO donor Schiff base

The crosslinked chloromethylated polystyrene (PSCH₂–Cl) reacts with the Schiff base, derived from condensation of PSCH₂–Cl with 3-formylsalicylic acid and salicylhydrazide to form a polystyrene-anchored Schiff base, PSCH₂–LH₃ (1). Compound 1 reacts with a number of metal ions to form polystyrene-anchored coordination compounds, PSCH₂–LHM?·?DMF (where M?=?Cu, Zn, Cd, UO₂, and MoO₂), PSCH₂–LHM′?·?3DMF (where M′?=?Mn, Co, and Ni), PSCH₂–LHFeCl?·?2DMF, and PSCH₂–LHZr(OH)₂?·?2DMF. The polystyrene-anchored coordination compounds have been characterized by elemental analyses, spectra (infrared, reflectance, and electron spin resonance) and magnetic susceptibility measurements. The polystyrene-anchored compounds are magnetically dilute. Shifts in band positions of the groups involved in coordination have been utilized to find tridentate ONO donor behavior of 1. The polystyrene-anchored Zn(II), Cd(II), Zr(IV), MoO₂(VI), and UO₂(VI) compounds are diamagnetic, while Mn(II), Co(II), Ni(II), Cu(II), and Fe(III) compounds are paramagnetic. The polystyrene-anchored Cu(II) compound is square planar; Zn(II) and Cd(II) compounds are tetrahedral; Co(II), Ni(II), Mn(II), Fe(III), MoO₂(VI), and UO₂(VI) compounds are octahedral; and Zr(IV) compound is pentagonal bipyramidal.     

A fast and precise heterometric determination of thallium(I) with sodium tetraphenylborate

The heterometric titration of thallium(I) with sodium tetraphenylborate, at various pH values and in the presence of salts and different complexing agents, was studied; 1.5–0.75 mg of thallium(I) could be determined within 3–4 min, and the error was negligible. Of the complexing agents studied, sodium pyro- and tripolyphosphate had a specific influence, raising the sensitivity about 4-fold, and no interference was caused by the presence of 30–130-fold molar excesses of the following metals: Ca, Mg, Zn, Mn, Co, Ni, Fe(III), Al, UO₂(II), Cd, Cu(II), Pb, Bi(III), Ag, V(V), Mo(VI) W(VI) and Th. Pd, Au(III) and Pt(IV) did not interfere.     

Carbohydrazone polychelates: Synthesis,physicochemical characterization,solid state conductance and biological studies

The polychelates of Ti(III), VO(IV), Cr(III), Mn(III), Fe(III), Zr(IV), MoO₂(VI) and UO₂(VI) with the chelating hydrazone derived from 2,4-dihydroxy-5-acetylacetophenone and carbohydrazide have been synthesized. The polychelates have been characterized on the basis of elemental analyses, IR, magnetic moment, electronic spectral data and thermal analysis. Various kinetic parameters have been determined from the thermal data and decomposition follows first order kinetics. The solid—state electrical conductivity has been measured over 40–130°C-temperature range and all the compounds showed semiconducting behavior as their conductivity increases with increase in temperature. The ligand and its polychelates have also been screened for their antimicrobial activities using various microorganisms and all of them were found to be active against the organisms.     

Selective and quantitative separation of zinc and lead from other elements by cation-exchange chromatography in hydrohalic acid-acetone solutions

Zinc and lead can be separated from Cd, Bi(III), In and V(V) by eluting these elements with 0.2M hydrochloric acid in 60% acetone from a column of AG50W-X8 cation-exchange resin, zinc and lead being retained. Mercury(II), Tl(III), As(III), Au(III), Sn(IV), Mo(VI), W(VI) and the platinum metals have not been investigated quantitatively, but from their distribution coefficients, should also be eluted. Vanadium(V), Mo(VI) and W(VI) require the presence of hydrogen peroxide. Zinc and lead can be eluted with 0.5M hydrochloric acid in 60% acetone or 0.5M hydrobromic acid in 65% acetone and determined by AAS; the alkali and alkaline-earth metal ions, Mn(II), Co, Ni, Cu(II), Fe(III), Al, Ga, Cr(III), Ti(IV), Zr, Hf, Th, Sc, Y, La and the lanthanides are retained on the column, except for a small fraction of copper eluted with zinc and lead. Separations are sharp and quantitative. The method has successfully been applied to determination of zinc and lead in three silicate rocks and a sediment.     

Diphenic acid as a selective reagent for the amperometric determination of thorium(IV)

Th(IV) has been titrated amperometrically at an applied e.m.f of −1.0 V (dropping mercury electrode vs. SCE) with diphenic acid (neutralized with sodium hydroxide). Th(IV) in the range 8.0–60.0 mg/100ml can be determined with an error of ±0.5%. A number of foreign ions including Ce(IV), Zr(IV), La(III), U(IV), U(VI) do not interfere even if present in excess but traces of Ti(IV) do. The method is rapid and selective and has been used for the determination of Th(IV) in monazite sand.     

Synthesis and physicochemical studies of some semicarbazone complexes

The Schiff base derived from 2,4-dihydroxy-5-acetylacetophenone and semicarbazide and its complexes with Ti(III), VO(IV), Cr(III), Mn(III), Fe(III), Zr(IV), MoO₂(VI), and UO₂(VI) ions have been synthesized. The complexes have been characterized on the basis of elemental analyses, IR, magnetic moment, electronic spectral data, and thermal analysis. Various kinetic parameters have been determined from the thermogravimetric analysis data, and decomposition follows the first-order kinetics. The solid state electrical conductivity has been measured over 313–403 K temperature range, and all the compounds showed semiconducting behavior as their conductivity increases with an increase in temperature. The ligand and its complexes have also been screened for their antimicrobial activities, and all of them were found to be active against various microorganisms. The text was submitted by the authors in English.     

Selective separation of indium from zinc, lead, gallium and many other elements by cation-exchange chromatography in hydrohalic acid-acetone medium

Indium can be separated from Zn, Pb(II), Ga, Ca, Be, Mg, Ti(IV), Mn(II), Fe(III), Al, U(VI), Na, Ni(II) and Co(II) by selective elution with 0.50M hydrochloric acid in 30% aqueous acetone from a column of AG50W-X8 cation-exchange resin, all the other elements being retained by the column. Lithium is included in the elements retained by the column when 0.35M hydrochloric acid in 45% aqueous acetone is used for eluting indium, but the elution of indium is slightly retarded. Ba, Sr, Zr, Hf, Th, Sc, Y, La and the lanthanides, Rb and Cs should also be retained according to their distribution coefficients. Cd, Bi(III), Au(III), Pt(IV), Pd(II), Rh(III), Mo(VI) and W(VI) can be eluted with 0.20M hydrobromic acid in 50% aqueous acetone before the elution of indium, and Ir(III), Ir(IV), As(III), As(V), Se(IV), Tl(III), Hg(II), Ge(IV), Sb(III) and Sb(V), though not investigated in detail, should accompany these elements. Relevant distribution coefficients and elution curves and results for analyses of synthetic mixtures of indium with other elements are presented.     

Rapid and selective method for the spectrophotometric determination of tin using potassium ethylxanthate

Tin (II) forms a yellow complex with potassium ethylxanthate which can be extracted into chloroform. Tin is determined spectrophotometrically by measuring the absorbance at 360 nm. Beer's law is obeyed up to 120 g of Sn in the aqueous phase with a Sandell sensitivity of 0.013 g Sn/cm². Metal ions such as Ti(IV), Cr(VI), Mn(II), Cu(II), Zn(II), Al(III), U(VI), W(VI), Th(IV) and Zr(IV) do not interfere, but Mo(VI), Co(II) and Bi(III) do. Interference due to Fe(II, III), Ni(II) and V(V) is checked by suitable masking agents. Analysis of some synthetic and industrial samples has been carried out by the proposed method.     

Potentiometric and Thermogravimetric Studies on Some Metal–Oxine–Sulphadrugs ternary Complexes

Formation constants (logK _MAL ^MA) of the mixed complexes of the type M–A–L (where M=Mn(II), Co(II), Ni(II), Cu(II), Ce(III), Th(IV), and UO₂(II); A=oxine and L=sulphamerazine or sulphadiazine) have been determined pH-metrically in 60% (v/v) ethanol–water mixture at 25°C and constant ionic strength (μ=0.1 M NaCl). The mode of chelation was ascertained by conductivity measurements. The stability sequence with respect to metal ions have been found to be Cu(II)>Ni(II)>Co(II)>Mn(II) and Th(IV)>UO₂(II)>Ce(III). CuAL ternary solid complexes have been prepared and characterized on the basis of elemental analysis and IR-spectroscopy. The thermal degradations of the prepared complexes are discussed in an attempt to assign the intermediate compounds formed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Synthesis,characterization, and biological studies of some Schiff base complexes

The synthesis of a new Schiff base derived from 2-hydroxy-5-chloroacetophenone and 4-amino-5-mercapto-3-methyl-1,2,4-triazole and its coordination compounds with Ti(III), VO(IV), Cr(III), Mn(III), Fe(III), Zr(IV), MoO₂(VI), and UO₂(VI) are described. The ligand and the complexes have been characterized on the basis of analytical, electrical conductance, molecular weight, IR and electronic spectra, magnetic susceptibility measurements, and thermogravimetric analysis. The ligand acts as a dibasic tridentate molecule. Antibacterial activities of the ligand and its metal complexes have been determined by screening the compounds against E. coli, S. typhi, P. aeruginosa, and S. aureus. The solid state de electrical conductivity of the ligand and its complexes have been measured over 313–403 K, and the complexes were found to be of semiconducting nature. The article was submitted by the authors in English.