Antimony(III) and bismuth(III) halide complexes of 2-methyl-benzoxazole

In the antimony(III) and bismuth(III) complexes of 2-methyl-benzoxazole: SbX₃·L (X = Cl, Br), SbI₃·2.5L, MX₃·L·H₂O (M = Sb, X = I; M = Bi, X = Cl, Br), SbCl₄·HL, SbBr₅·2HL, BiCl₅·2HL. Bi₂X₉·3HL (X = Br, I) the ligand is O-bonded to the metal.     

Influence ofpH and concentration of complexing agents on fluorescence of europium (III) ethylenediaminetetraacetic acid and europium (III) nitrilotriacetic acid complexes in aqueous solutions

The fluorescence of aqueous solutions of Eu(III) complexes withEDTA andNTA has been investigated. Intensities of the fluorescence bands have been measured as a function of complexone concentrations in the solutions and thepH. The results are interpreted in terms of the different forms of Eu(III) complexes and their relative stabilities.

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Einfluß vonpH und Konzentration der Komplexbildner auf die Fluoreszenz der Komplexe des Europium (III) mit Ethylendiamintetraessigsäure und Nitrilotriessigsäure in wäßrigen Lösungen

Zusammenfassung Die Fluoreszenz von wäßrigen Lösungen der Komplexe des Europium(III) mit Ethylendiamintetraessigsäure und Nitrilotriessigsäure wurde untersucht. Die Intensitäten der Fluoreszenzbanden in Abhängigkeit vonpH und Konzentration der Komplexbildner wurden auf der Basis vorkommender Komplexgeometrien und deren Stabilitäten interpretiert.

     

209Bi NQR study of bismuth(III) complexes

Potassium pentafluorobismuthate(III), nitrate-chloride Bi^III complexes MBiCl₃NO₃ (M=K, (NH₂)₂CNH₂), sulfate-chloride Bi^III complexes MBiCl₂SO₄ (M=K, Rb, NH₄, (NH₂(₂CNH₂), and Bi^III complexonates with the anions of ethylenediaminetetraacetic acid M[Bi(edta)]₂·nH₂O (M=Mg, Ca, Ni, Cd) and nitrilotriacetic acid Bi(nta)·2H₂O, and Bi(nta)·3thio·H₂O (thio is thiourea) were studied by²⁰⁹Bi NQR spectroscopy. A second-order phase transition was observed in K₂BiF₅ at 100 K. The compounds Bi(nta)·2H₂O, (NH₂)₂CNH₂BiCl₃NO₃, and MBiCl₂SO₄ (M=K, NH₄) are piezoelectrics. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2237–2240, November, 1998.     

Determination of free acid in antimony(III) and bismuth(III) solutions

A method for the determination of free acid in antimony(III) and bismuth(III) solutions is given. A solution of the disodium salt of EDTA, 2-3 % in excess of the stoichiometric amount, is added to the metal salt solution and titrated with sodium hydroxide solution potentiometrically or visually using a mixed indicator. The error in the method is less than 0.5 %.     

Influence ofpH and concentration of complexing agents on fluorescence of samarium(III), gadolinium(III), and terbium(III)—Ethylenediaminetetraacetic acid or nitrilotriacetic acid complexes in aqueous solutions

The fluorescence intensity of aqueous solutions of Sm(III), Gd(III) and Tb(III) complexes withEDTA orNTA was investigated as a function of complexone concentration over a widepH range. For Sm(III) and Tb(III) complexes the ratio of intensities of hypersensitive and allowed bands was calculated in order to obtain information about intensity borrowing of the fluorescence bands as a result of vibronic coupling.     

Spectrophotometric study of the complexes of hydroxyethylethylenediaminetriacetic acid with bismuth(III), copper(II) and lead(II)

The bismuth(III), copper(II) and lead(II) hydroxyethylethylenediaminetriacetic acid systems were investigated in detail. Evidence for the formation of species BiX, Bi(OH)X⁻, CuHX, CuX⁻, PbHX and PbX⁻ is presented and their stability constants given.     

The effect of temperature on the formation of bismuth(III) monocysteine and monothiosemicarbazide complexes

The stability constants of monocomplexes of cysteine (H₂Cys) and thiosemicarbazide (Tsc) with bismuth(III) at 288, 313 and 333 K in 0.5 M HClO₄ and an ionic strength of 2(NaClO₄) were determined by spectrophotometry. On the basis of a substantial difference in the stability constants of bismuth monocomplexes with H₂Cys and Tsc, the high acidity of the investigated solutions, and known coordination modes of these ligands in crystalline compounds, the formation of Bi(HCys-O,S)²⁺ and Bi(Tsc-N, S)³⁺ is suggested.     

Tris-Nethyl, m-tolyl)dithiocarbamato complexes of arsenic(III), antimony(III) and bismuth(III)

Tris-N(ethyl, m-tolyl) dithiocarbamato complexes of arsenic(III), antimony(III) and bismuth(III) abbreviated as As(S₂CNRR′)₃ Sb(S₂CNRR′)₃ and Bi(S₂CNRR′)₃, respectively, where R  C₂H₅ and R′  m-C₆H₄CH₃, have been synthesized. These complexes have been characterized on the basis of elemental analyses, molecular weight determinations, conductance measurements and infrared spectral studies. Thermal studies of these complexes have been carried out in nitrogen and air to determine their modes of decomposition. Kinetic parameters, such as apparent activation energy and order of reaction, have been determined by the graphical method of Coats and Redfern [1].     

Interaction of bismuth(III) oxide with formic acid solutions

The interaction of bismuth(III) oxide with formic acid solutions at 22 and 55°C was studied using X-ray powder diffraction, thermogravimetry, electron microscopy, IR spectroscopy, and chemical analysis. Solubility curves were found to comprise two branches due to formates of compositions Bi(COOH)₃ and BiOCOOH forming in the system. Thermal decomposition of bismuth formates is shown to be a promising route for the synthesis of metallic bismuth, as well as of tetragonal (β) and monoclinic (α) bismuth oxides.     

Reaction between copper(I)-thiourea and bismuth(III)-thiourea complexes in presence of iodide. New spot-tests for copper(II) and bismuth(III)

New and very simple spot tests are described for the detection of Bi(III), Cu(II) and I(-) ions with limits of detection of 3, 8, and 75 mug/0.05 ml respectively. Tests are also described for such combinations as Bi(III) + I(-); Bi(III) + Cu(II); and Bi(III) + Cu(II) + I(-). All the tests are based on the formation of an orange or red-orange precipitate of bismuth(III)-copper(I)-iodide-thiourea complex, for which the formula [Bi(tu)(3)I(3).Cu(tu)(3)I] (where tu = thiourea) is proposed. This complex is produced in various ways by the interaction of Bi(III), Cu(II), and I(-) ions with thiourea. Most cations and anions do not interfere, but Tl(I), Cs(I), SO(2-)(3), S(2)O(2-)(3), EDTA, and oxidizing ions such as NO(-)(2), IO(-)(3), IO(-)(4), BrO(-)(3), and MnO(-)(4) do. The complex hexakis(thioureato)sulphatomonoaquodicopper(I) [Cu(2)(tu)(6)SO(4).H(2)O] is proposed as a new spot-test reagent for Bi(III) and I(-) ions, although the sensitivity for the latter is poor.     

Indium(III), antimony(III) and bismuth(III) dihalide complexes with tridentate, anionic thio- and selenosemicarbazonato ligands

Some indium(III), antimony(III) and bismuth(III) dihalide complexes containing deprotonated, tridentate thio- and selenosemicarbazone ligands were prepared and were fully characterized by spectroscopic methods. In addition, the crystal structures of some of the compounds were obtained. TGA and DSC analyses were carried out on selected samples to assess their suitability as single-molecule precursors for metal selenide nanomaterials.     

Optical metal-to-ligand charge-transfer of 2,2′-bipyridyl complexes of antimony(III) and bismuth(III)

The complexes [M(2,2′-bipyridyl)X₃], with M = Sb, Bi and X = Cl, Br, I, are characterized by long-wavelength metal-to-ligand charge-transfer (MLCT) bands which determine the colours of these compounds in the solid state. The energy of the MLCT bands depends on the reducing strength of the metal and the extent of sp mixing of the lone electron pair at the metal.     

Precipitation of bismuth(III) salicylates from mineral acid solutions

Powder X-ray diffraction, IR spectroscopy, Raman spectroscopy, thermogravimetry, and chemical analysis were used to study the precipitation of bismuth(III) salicylates from perchloric, nitric, and hydrochloric acid solutions as dependent on the salicylate ion concentration, temperature, and pH. Depending on the synthesis parameters, precipitation from perchloric and nitric acid solutions yields monosalicylate BiOC₇H₅O₃ or disalicylate Bi₂O(C₇H₅O₃)₄.     

Stability of ternary copper—nitrilotriacetic acid complexes

A copper-selective electrode was used to investigate ternary copper—nitrilotriacetic acid complexes by means of combined pH and pM measurements. The theory presented for the evaluation of the stability of mixed-ligand complexes is based on the conditional constants. The emphasis is on the formation of 1:1:1 complexes of the type copper(II)—NTA—(hydroxide, amino acid, ammonia, triphosphate).     

Thermodynamics of heteroligand mercury(II) complexes with nitrilotriacetic acid and ethylenediamine in aqueous solution

Formation of heteroligand complexes HgNtaEn⁻ and Hg(Nta)₂En⁴⁻, where Nta³⁻ is nitrilotriacetate ion and En is ethylenediamine, was studied by means of direct calorimetry, potentiometry, and NMR spectroscopy at 298.15 K and ionic strength I = 0.5 (KNO₃).     

Formation of bismuth(III) N-methylthiourea complexes in aqueous solutions

The formation constants of bismuth(III) methylthiourea complexes in aqueous solution were determined at 298 K and an acidity of 2 M HClO₄ using the “ligand-oxidized ligand species” potentiometric method and the methylthiourea (mtu)-symmetric dimethylformamidine disulfide (mFDS) redox pair. The formation function was obtained, and the conditional (β _n ^*) and true (β _n ) formation constants of Bi(mtu) _n ³⁺ (1 ≤ n ≤ 8) were calculated. The value of β₁ and the formation of complexes with coordination numbers higher than six was confirmed by spectrophotometry.     

A study on the fluoride complexes of plutonium(III), samarium(III) and bismuth(III) using fluoride ion-selective potentiometry

Stability constants of the fluoride complexes of Pu(III), Sm(III) and Bi(III) in 1.0M NaClO₄/HClO₄ medium at 23±1°C have been determined by potentiometry using a fluoride ion-selective electrode. Plutonium was reduced to the trivalent state using quinhydrone with an excess to serve as holding reductant. The log values of concentration stability constants log ₁, log ₂, and log ₃ are 3.58, 6.40 and 12.61 for Pu(III), 3.23, 5.81 and 10.54 for Sm(III) and 3.69, 6.13 and 11.04 for Bi(III), respectively. The log ₂ values in all these cases have very large deviation and may be taken only as rough estimates.