Synthesis and polycondensation of some new organic tellurium compounds containing mono- and di-amino groups

Several new and known organic tellurium compounds containing amino groups (i.e. ArTeBr₃, Ar₂Te₂ and Ar₂Te, where Ar= 4-NH₂C₆H₄, 2-NH₂C₆H₄, 4-CH₃CONHC₆H₄ or 2-NH₂-5-NO₂-C₆H₃) were prepared by reacting aminoarylmercury chlorides with tellurium tetrabromide in glacial acetic acid. Bis(4-aminophenyl) telluride and bis(2-amino-5-nitrophenyl) telluride were polymerized with aromatic and aliphatic diacid chlorides (i.e. terephthaloyl chloride and sebacoyl chloride), as well as with toluene di-isocyanate, leading to new organic tellurium polyamides and polyurea. All organic tellurium compounds and their condensation polymers were characterized by elemental analyses, IR, ¹H and ¹³C NMR, and mass spectroscopy. The thermal stabilities of the resulting polymers were determined by thermogravimetric and derivative thermogravimetric techniques. © 1998 John Wiley & Sons, Ltd.     

The reaction of hydrogen chloride with bis (p-ethoxyphenyl)telluride,a possible route to pure tellurium

The reaction of hydrogen chloride with bis(p-ethoxyphenyl)telluride is investigated and shown to give essentially phenetole (C₆H₅COEt), tellurium, and bis(p-ethoxyphenyl)tellurium dichloride. Spectroscopic methods (UV–visible, ¹²⁵Te NMR) show that some bis(p-ethoxyphenyl)ditelluride is produced. This is believed to arise from a side reaction of organic telluride with an intermediate organyltellurenyl chloride which is considered to arise from initial proton attack at the Te–C bond of the telluride. The ditelluride reacts with HCl to deposit 80% of its tellurium content as the element; phenetole is the other major product. Use of a spin-trap reagent gave no evidence of radical intermediates. An attempt to develop a reaction sequence to prepare high-purity tellurium is described. Although a purity of 99.985% could be achieved, overall yields are not economic, unless very highpurity tellurium is required. The method described is, however, very effective for the removal of traces of tin, lead, arsenic and antimony and can significantly reduce the copper, iron and selenium content; for example, one treatment of an alloy (Te, 75%; Se, 25%) gave a sample of tellurium containing 40 ppm selenium.     

Thermal stabilization of inorganic and organically- bound tellurium for electrothermal atomic absorption spectrometry

The thermal stabilization of inorganic tellurium(IV) and organically-bound tellurium for electrothermal atomic absorption spectrometric determination of the element was studied with the use of the isotope tellurium-127m. Of the 19 metals and potassium iodide tested, 15 metals had a stabilizing effect on inorganic tellurium; among the 9 metals tested with organically-bound tellurium, only 3 exhibited an effect. The most effective metals for stabilizing inorganic tellurium were cadmium, copper, palladium, platinum and zinc, while the best agents for stabilization of organically-bound tellurium were silver, palladium and platinum; in the presence of palladium and platinum, tellurium in both forms could be heated in the graphite tube to 1050°C without losses. Attempts were made to determine tellurium in human whole blood and garlic, but the concentrations were found to be below the detection limits of 3 ng ml^-1 and 140 ng g^-1, respectively.     

Intestinal absorption of tellurium studied with stable tracers

An investigation on tellurium metabolism by administration of stable tellurium isotopes¹²⁴Te and¹²⁶Te has been performed. Fractional intestinal absorption was determined in rabbits by the double tracer technique. The investigated subjects were given an enriched solution of one tellurium isotope orally and a few minutes later an enriched solution of the other isotope intravenously. The¹²⁴Te and¹²⁶Te contents in plasma samples were determined by proton nuclear activation. The methodology described offers a means to study tellurium metabolism in humans without radiation risk.     

Coexistence of Tellurium Cations and Anions in Phosphonium-Based Ionic Liquids

Elemental tellurium readily dissolves in ionic liquids (ILs) based on tetraalkylphosphonium cations even at temperatures below 100 °C. In the case of ILs with acetate, decanoate, or dicyanamide anions, dark red to purple colored solutions form. A study combining NMR, UV-Vis and Raman spectroscopy revealed the formation of tellurium anions (Te_n)²⁻ with chain lengths up to at least n=5, which are in dynamic equilibrium with each other. Since external influences could be excluded and no evidence of an ionic liquid reaction was found, disproportionation of the tellurium is the only possible dissolution mechanism. Although the spectroscopic detection of tellurium cations in these solutions is difficult, the coexistence of tellurium cations, such as (Te₄)²⁺ and (Te₆)⁴⁺, and tellurium anions could be proven by cyclic voltammetry and electrodeposition experiments. DFT calculations indicate that electrostatic interactions with the ions of the ILs are sufficient to stabilize both types of tellurium ions in solution.     

Reuse of decayed tellurium dioxide target for production of iodine-131

Iodine-131 was generated by irradiation of natural tellurium dioxide in a nuclear reactor. After irradiation the tellurium dioxide was transferred to hot cell and heated in a quartz furnace at ~700 °C. The Iodine-131 was distilled and collected in carbonate/bicarbonate buffer and used for thyroid cancer patients. The tellurium dioxide used was >99 % pure. During nuclear reaction nanogram tellurium was consumed to produce ¹³¹I, although significant loss of target material may occur in heating process. In dry distillation technique no chemical was added to irradiated target material. After ¹³¹I separation tellurium dioxide was decayed for 8 years in radioactive waste management facility. The decayed TeO₂ was recovered, melted and crushed for desired mesh size. The TeO₂ was sealed in Al capsule for re-irradiation purposes. The separation of ¹³¹I was carried out via dry distillation. The purity and yield of ¹³¹I separated from both of the irradiated new and irradiated re-used tellurium dioxide targets were comparable.     

高分子载体Lewis酸催化剂——四氯化碲-聚苯乙烯复合物

<正> 高分子催化剂作为功能性高分子的重要组成部分具有许多独特的优点和功能,是目前催化剂研究的发展方向之一,日益受到重视。 Neckers等将AlCl_3与聚苯乙烯反应制成的高分子载体催化剂,对酯化、缩醛等反应有较好的催化作用,我们也曾制备了一系列聚苯乙烯与强Lewis酸的复合物催化剂,如聚苯乙烯-五氯化锑复合物(Ps-SbCl_5)、聚苯乙烯-四氯化钛复合物(Ps-TiCl_4)、聚苯乙烯-四氯化锡复合物(Ps-SnCl_4)、聚苯乙烯-三氯化铁复合物(Ps-FeCl_3)等,它们具有较高的稳定性和良好的催化效能.为了研究弱Lewis酸与高分子载体的复合能力以及它们是否还具有催化活性,为了研究各种Lewis酸用高分子载体固载化的规律     

Ion chromatography–hydride generation‐atomic fluorescence spectrometry speciation of tellurium

The speciation of tellurium was carried out using atomic fluorescence spectrometry as an element‐specific detector in hybridization with liquid chromatography and hydride generation. Good resolution could be obtained by anion‐exchange chromatography with complexing agents, using a mobile phase with 8 mM EDTA and 2 mM potassium hydrogenphthalate. Analysis time was less than 6 min. Calibration graphs were linear between 2 and 100 µg l^?1. Detection limits were 0.6 µg l^?1 and 0.7 µg l^?1 for tellurium(VI) and tellurium(IV) respectively. The method was applied to the speciation of tellurium in drinking water and wastewater samples from different metallurgical industries. Copyright © 2005 John Wiley & Sons, Ltd.     

Eigenschaften von Chalkogen-Chalkogen-Bindungen. XII. Reversible Tellurierung von Tetraisopropyldiphosphan; Stabilisierung von Tellurobis(diisopropylphosphan) als Tetracarbonylchromkomplex

Properties of Chalcogene-Chalcogene Bonds. XII. Reversible Telluration of Tetraisopropyldiphosphane, Stabilisation of Tellurobis(diisopropylphosphane) as Tetracarbonylchromium Complex Tetraisopropyldiphosphane 1 reacts with elemental tellurium by tellurium atom insertion to give tellurobis(diisopropylphosphane) 2. 2 is also available from sodium telluride with chlorodiisopropyl phosphane. ^lH, ^l3C, ^3lP and ^l25Te n.m.r. spectra confirm that in solution 2 is in an equilibrium with the educt 1 and elemental tellurium. Reaction of this equilibrium mixture with tetracarbonyl(norbornadiene)chromium(0) provides tetracarbonyl[tellurobis(diisopropylphosphane)]-chromium(0) 3. 3 was isolated in pure state as stable compound; different from 2,3 does not suffer from loss of tellurium at room temperature.     

A New Polarographic Adsorptive Catalytic Wave for the Determination of Trace Tellurium in Smog Dust and Wheat Flour

Linear-sweep polarography of tellurium in sulfuric acid solution containing methylene blue produces a wave at −0.82 V (vs SCE). In a cathodic sweep, the derivative peak current is directly proportional to the concentration of tellurium over the range 4 × 10⁻⁹to 1 × 10⁻⁷g/ml, and the detection limit is 2 × 10⁻⁹g/ml. The polarographic wave is an adsorptive catalytic hydrogen wave. This method has been applied to the determination of trace amounts of tellurium in smog dust and wheat flour, with satisfactory results.     

Synthesis and characterization of tin telluride inorganic/organic composite materials with nanoscale periodicity through solution-phase self-assembly: a new class of composite materials based on Zintl cluster self-oligomerization

In this work, we demonstrate the synthesis of semiconducting tin telluride inorganic/organic composite materials with nanoscale periodicity prepared using solution phase self-assembly. Oligomerization of anionic SnTe ₄ ^4? clusters by halogen-mediated tellurium elimination in the presence of surfactant leads to the formation of a meosotructured composite. The composites initially forms as a mixture of mesophases, usually some combination of a layered phase and a phase based on cylindrical building blocks. Post synthetic treatment leads to a solid-state structural change which converts the composites to a single mesophase architecture with a hexagonal honeycomb (p6mm) morphology on the nanometer length scale. A by product of this reaction, however, is bulk tellurium. Changes in the electronic structure of the materials during synthesis and solid-state restructuring are probed using electron spin resonance (ESR) spectroscopy.     

The determination of tellurium in weathered outcrop,mineralized and barren rock

Sensitive and specific methods have been developed for the determination of tellurium in a wide variety of rocks and minerals. X-ray fluorescence is used for concentrations above 1 μg g^-1 and carbon furnace atomization a.a.s. for concentrations of 0.01–1μg g^-1. The tellurium is separated by precipitation as elemental tellurium after dissolution in acid; alternative dissolution procedures have been investigated.     

Evaluation of a new multi-walled carbon nanotube paste electrode modified with Alizarin Red S for the determination of tellurium by differential pulse stripping voltammetry

A new modified carbon paste electrode based on multi-walled carbon nanotube and Alizarin Red S acts as a chelating agent for tellurium(IV) ions, is described. The electrochemical responses were found to be analytically suitable to develop a method for the determination of tellurium at low concentration levels. Under optimised operational conditions, the sensor exhibited linear behaviour in the range of 2.0–300 ng mL^?1 (correlation coefficient: 0.9982) with a detection limit of 0.45 ng mL^?1. The results indicate that the sensor is sensitive and effective for the determination of tellurium in water samples and certified reference materials.     

Radiochemical separation of110mAg,210Pb,127Te and131I from aqueous nitric acid solution by bis-2-(butoxyethyl ether)

A bis-2-(butoxyethyl ether) (DBC) solvent extraction method has been developed for the radiochemical separation of^110mAg,²¹⁰Pb,¹²⁷Te and¹³¹I in varying concentrations of aqueous HNO₃. Various factors were examined to determine the optimum conditions of extraction. The effect of various masking agents has been studied. The extraction of¹³¹I is enhanced to 99% at 2.4M HNO₃ in the presence of KSCN.¹³¹I was stripped into aqueous sodium hydroxide from the oxygenated organic extractant. The method was then applied for the recovery of¹³¹I from neutron irradiated tellurium metal. The mechanism and reactivity of DBC with metal ions is described.     

Adsorption and colloidal behaviour of traces of tellurium(IV) in aqueous solutions

Various NaCl solutions containing traces of tellurium(IV) have been prepared. The effects of tellurium(IV) concentration and pH on the adsorption of tellurium(IV) on filter paper have been studied by filtration method. The effects of NaCl concentration, tellurium(IV) concentration and pH on the formation of a colloid have been also studied by ultracentrifugation and ultrafiltration methods. It has been found that tellurium(IV), at concentrations below about 10^–10M, in neutral NaCl solutions is adsorbed on filter paper and shows colloidal behaviour.     

Catalytic determination of ultra trace amounts of tellurium by 2.5-order differential oscillopolarography

A highly sensitive and selective catalytic method with 2.5-order differential oscillopolarographic detection is described for the determination of tellurium, based on its activation effect on the slow Pd(II)-catalyzed reaction of sodium hypophosphite and methyl red in hydrochloric acid medium at 100?°C. Methyl red exhibited a sensitive 2.5-order differential polarographic wave at –0.35 V ¶(vs. SCE) in the supporting electrolyte of pH 5.0 acetate buffer solution and was chosen as the indicating component for the indirect determination of tellurium. A calibration curve of tellurium in the range of 0.02–2.0 ng mL^–1 was obtained by the fixed-time procedure. The detection limit was 0.007 ng mL^–1. Possible interferences by co-existing substances were examined. The new method has been used to analyze trace tellurium in organs of white mice with satisfactory results. RSD was 0.54% to 2.10%, recovery 98.4% to 95.7%. The mechanism is also discussed.     

Spectrophotometric determination of tellurium in concentrates and brasses by chloroform extraction of the tellurium (IV) hexabromide-diantipyrylmethane complex after separations by iron collection and xanthate extraction

A method for determining 0.0001–0.10% of tellurium in copper, nickel, molybdenum, lead and zinc concentrates is described. After sample decomposition, tellurium is separated from most of the matrix elements by co-precipitation with hydrous ferric oxide from an ammoniacal medium. After reprecipitation of tellurium and iron, the precipitate is dissolved in 12M hydrochloric acid, tellurium(VI) is reduced to the quadrivalent state by heating, and separated from iron, lead and other co-precipitated elements by chloroform extraction of its xanthate. The yellow ion-association complex formed between tellurium(IV) hexabromide and diantipyrylmethane is extracted into chloroform from a 2M sulphuric acid-0.6M potassium bromide medium. The molar absorptivity of the complex is 1.82 × 10³ l.mole⁻¹.mm⁻¹ at 336 nm, the wavelength of maximum absorption. Small amounts of iron, copper and molybdenum are co-extracted as xanthates under the proposed conditions but do not cause error in the result. Interference from antimony, which is co-extracted as the chloro-complex, is eliminated by washing the extract with water. The proposed method is also applicable to brasses.     

1,2-Ditellurolane: A new synthetic method, structure and chemical reactions

A simple method for the synthesis of 1,2-ditellurolane is proposed, based on the reaction of elemental tellurium with 1,3-dihalopropane in a system of hydrazine hydrate and alkali followed by the effect of organic solvent on the first formed poly(trimethyleneditellurides). The products of the oxidation and reduction of 1,2-ditellurolane were characterized and its spectral characteristics were analyzed. Dedicated To Academician Of The Russian Academy Of Science Mikhail Grigor’evich Voronkov on his 85^th Birthday. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, 1705–1713, November 2006.     

Fast determination of molybdenum and tellurium by neutron activation analysis

The utilization of 14.6-min ¹⁰¹Mo and 25-min ^101gTe for the determination of molybdenum and tellurium in biological materials by radiochemical neutron activation analysis is described for the first time. Radioisotopes were separated from the samples activated in a thermal neutron flux of about l0¹⁴n cm^-2 s^-1. The radiochemical procedure for molybdenum involves extraction of Mo⁺⁺ from 6 M HCl into diethylether, re-extraction into water, precipitation as oximate, and measurement of the gamma activity of ¹⁰¹Tc. The tellurium was separated by reduction to the element with SO₂ in 3 M HCl, dissolution in HNO₃, and reprecipitation as the element for the measurement of radioactivity. The sensitivity was estimated at ca. 10 ng at the level of confidence of 95%. The methods were tested by analyzing NBS- standard Bovine Liver and Orchard Leaves for molybdenum; the concentrations found were 3.2 ± 0.1 μg g^-1 and 300 ± 60 ng g^-1, respectively. The tellurium content of bovine liver was estimated at 90 ± 15 ng g^-1.     

Thermodynamic properties of Iron—Tellurium alloys

Vapor pressures of tellurium of iron—tellurium alloys were determined between 550 and 900°C and between 0 and 67 at % Te by an isopiestic method. Activities and partial molar enthalpies of tellurium were calculated and integral free energies of formation were obtained by aGibbs-Duhem integration. Two statistical models were used to calculate activities in the hexagonal δ′-NiAs phase. Excellent agreement with the experimental values was obtained by assuming random distribution of iron atoms and iron vacancies in the defected (00 1/2) layers of the lattice. The interaction energy between iron vacancies was found to be 820 cal·g-atom^?1.