Homodinuclear glycolate derivatives of bismuth(V) and arsenic(III): synthesis and spectroscopic studies

Ligand bridged homodinuclear derivatives of bismuth(V) of the type, (1a–1d) [where R =–C(CH₃)₂CH₂CH(CH₃)–(1a),–CH(CH₂CH₃)CH₂–(1b),–CH(CH₃)CH(CH₃)–(1c),–CH(CH₃)CH₂–(1d)] have been synthesized by reactions of equimolar oxobis(triphenylbismuth)dichloride, {[Ph₃Bi]₂O}Cl₂ with glycols, HOROH in the presence of NaOMe. Reactions of sodiumtetraisopropoxoarsonate, NaAs(OPrⁱ)₄ with in 1 : 1 molar ratio yielded homodinuclear alkoxo derivatives of arsenic(III) containing glycols, (2a–2d). All compounds were characterized by elemental analysis, molecular weight determinations, IR and NMR (¹H and ¹³C) spectral studies.     

Synthesis and Characterization of Some New Triorganophosphorus, -Arsenic and -Antimony(V) Amido Derivatives

A number of triorganophosphorus, -arsenic, and -antimony(V) amido derivatives of the general formula R 2 R'ML 2 [where R = C 6 F 5 , C 6 H 5 ; R' = C 6 F 5 , C 6 H 4 CH 3 - p ; M = P, As or Sb and L = imidazole, benzimidazole, 2-methyl benzimidazole, indazole, and 1,2,3,4-tetrahydrocarbazole] have been synthesized by the metathetical reaction of triorganophosphorus, -arsenic, and -antimony(V) halides and the corresponding imidazoles in the presence of triethyl amine. These compounds have been characterized by elemental analysis, IR and NMR ( 1 H and 19 F) spectroscopy, conductance, and molecular weight data. The Van't Hoff factor "i" and molar conductance data of the compounds revealed them to be monomeric and nonionic in nature. On the basis of spectroscopic studies, a tentative trigonal bipyramidal structure has been assigned for these amido derivatives.     

Synthesis,characterization, antifungal,antibacterial, and antitumor activities of some tris(pentafluorophenyl)arsenic(V) derivatives

A series of tris(pentafluorophenyl) arsenic(V) derivatives of the type (C₆F₅)₃AsL₂, (C₆F₅)₃As(Cl)(L) [L =  OCOC₆H₄(o‐OH),  OCOC‐(OH)(C₆H₅)₂, and 2‐(6‐OCH₃C₁₀H₆)CH(CH₃) COO ], and cycloarsenates, (R = C₆H₅, p‐CF₃C₆H₄, and p‐OCH₃C₆H₄) have been isolated and characterized by elemental analysis and spectroscopic data (infrared; ¹H, ¹⁹F, and ¹³C NMR). These compounds were screened for their in vitro antifungal, antibacterial, and antitumor activities and were found to show moderate to significant activity. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:181–187, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20593     

Inorganic speciation of As(III, V), Se(IV, VI) and Sb(III, V) in natural water with GF-AAS using solid phase extraction technology

The paper presents a procedure for the multi-element inorganic speciation of As(III, V), Se(IV, VI) and Sb(III, V) in natural water with GF-AAS using solid phase extraction technology. Total As(III, V), Se(IV, VI) and Sb(III, V) were determined according to the following procedure: titanium dioxide (TiO₂) was used to adsorb inorganic species of As, Se and Sb in sample solution; after filtration, the solid phase was prepared to be slurry for determination. For As(III), Se(IV) and Sb(III), their inorganic species were coprecipitated with Pb-PDC, dissolved in dilute nitric acid, and then determined. The concentrations of As(V), Se(VI) and Sb(V) can be calculated by the difference of the concentrations obtained by the above determinations. For the determination of As(III), Se(IV) and Sb(III), palladium was chosen as a modifier and pyrolysis temperature was 800 °C. Optimum conditions for the coprecipitation were listed for 100 ml of sample solution: pH 3.0, 15 min of stirring time, 40.0 μg l⁻¹ Pb(NO₃)₂ and 150.0 μg l⁻¹ APDC. The proposed method was applied to the determination of trace amounts of As(III, V), Se(IV, VI) and Sb(III, V) in river water and seawater.     

Synthesis and some reactions of tris (pentafluorophenyl) antimony compounds

(C₆F₅)₃Sb has been found to react with interhalogens and halo-pseudohalogens, IX(X = Cl, Br, N₃ and NCO), pseudohalogen (SCN), and elemental sulphur to give oxidative addition products (I–VI). (C₆F₅)₃SbS(VI) may also be prepared by the reaction of (C₆F₅)₃SbCl₂ with H₂S. Metathetical reactions of (C₆F₅)₃SbCl₂ with appropriate metallic salts yield covalent pentacoordinate disubstituted products (V, VII–XII) of the general formula, (C₆F₅)₃SbY₂ (Y = NCS, NCO, ?ONCMe₂, ?ONCMePh $\text{?NCO(CH}{}_2\text{)}{}_2\text{C}$O and p-NO₂C₆H₄OCO). Treatment of (C₆F₅)₃SbCl₂ with aqueous NaN₃ gives the binuclear oxo-bridge compound, [(C₆F₅)₃SbOSb(C₆F₅)₃](N₃)₂·(III) and (IV) are also accessible by displacement reaction of (I) or (II) with the corresponding metallic salt. Molecular weight, conductance measurements, and IR spectra on the new organoantimony(V) derivatives have been obtained.Reductive cleavage reactions of (C₆F₅)₃SbS with hexaaryldileads, Ar₆Pb₂(Ar = Phenyl, p-tolyl) produce (C₆F₅)₃Sb and the corresponding bis(triaryllead) sulphide but treatment of (C₆F₅)₃SbX₂(X = NCO, Cl) with Ar₆Pb₂ gave Ar₄Pb and Ar₂PbX₂ together with (C₆F₅)₃Sb.(C₆F₅)₃SbCl₂ and bis(triorganotin)sulphides undergo exchange of anionic groups.     

Synthesis and structural characterization of carbon-centered tris(pentafluorophenyl)silyl derivatives

A general method for the synthesis of carbon-centered tris(pentafluorophenyl)silyl derivatives (RSi(C₆F₅)₃) by reaction of trichlorosilanes (RSiCl₃) with pentafluorophenylmagnesium bromide was described. The crystal structures of obtained compounds were studied by X-ray diffraction analysis (7 structures). The peculiarities of crystal packing were analyzed by means of DFT calculations.     

Simultaneous determination of trace arsenic(III), antimony(III), total arsenic and antimony in Chinese medicinal herbs by hydride generation-double channel atomic fluorescence spectrometry

A new method was developed for simultaneous determination of trace arsenic and antimony in Chinese herbal medicines by hydride generation-double channel atomic fluorescence spectrometry with a Soxhlet extraction system and an n-octanol-water extraction system, respectively. The effects of analytical conditions on the fluorescence intensity were investigated and optimized. A water-dissolving and methanol-water-dissolving capability were compared. The contents of different species in five Chinese herbal medicines and their decoctions were analyzed. The concentration ratios of n-octanol-soluble As or Sb to water-soluble As or Sb were related to the kinds of medicine and the acidity of the decoction. Soxhlet extraction was found to be an effective method for plants pretreatment for determination of arsenic and antimony species in Chinese herbs; the interferences of coexisting ions were evaluated. The proposed method has the advantages of simple operation, high sensitivity and high speed, with 3σ detection limits of 0.094 μg g⁻¹ for As(III), 0.056 μg g⁻¹ for total As, 0.063 μg g⁻¹ for Sb(III) and 0.019 μg g⁻¹ for total Sb in a 1.0 g of the sample.     

Fluoride-fluorosulfates of arsenic (V) and arsenic (III)

The synthesis of AsF₃(SO₃F)₂ by the reaction AsF₃ + S₂O₆F₂→AsF₃(SO₃F)₂ is described. Various alternate routes leading to similar arsenic (V) fluoride-fluorosulfates are discussed. All materials are clear, viscous, strongly associated liquids of the general formula AsF_n(SO₃F)_5?n, with n ranging from about 2 to 4. The presence of fluorosulfate bridges is ascertained by IR and Raman spectra.The spectroscopic investigation is also extended to arsenic (III) fluoride- fluorosulfates.     

Syntheses and Properties of Tetrakis(pentafluorophenyl)tellurium,Te(C6F5)4, and Related Compounds — Single Crystal Structures of Tris(pentafluorophenyl)tellurium Bromide,Te(C6F5)3Br,Tris(pentafluorophenyl)tellurium Trifluoromethanesulfonate, [Te(C6F5)3][OSO2CF3], and Bis(pentafluorophenyl)tellurium Oxide,Te(C6F5)2O

Te(C₆F₅)₄ was prepared from the reactions of TeCl₄ or Te(C₆F₅)₂Cl₂ with Grignard reagents or AgC₆F₅ in moderate to good yields. Substitution reactions with Me₃SiX (X = Cl, Br, OSO₂CF₃), with equimolar amounts of Br₂, with AgNO₃ and with H[BF₄] or BF₃·OEt₂ yielded the Te(C₆F₅)₃X derivatives (X = Cl, Br, OSO₂CF₃, NO₃, BF₄). Oxidation reactions of Cd, Hg, and Pd⁰ complexes led to Te(C₆F₅)₂ and the corresponding bis(pentafluorophenyl) derivatives M(C₆F₅)₂ (M = Cd, Hg, Pd) and with InBr to In(C₆F₅)₂Br. From very slow hydrolysis of Te(C₆F₅)₄ the oxide Te(C₆F₅)₂O was prepared. The thermal decomposition, the NMR and mass spectra of the partially new compounds are discussed. The crystal structures of Te(C₆F₅)₃Br (monoclinic, P2₁/a, Z = 4), [Te(C₆F₅)₃][OSO₂CF₃] (monoclinic, P2₁/n, Z = 16) and [Te(C₆F₅)₂O]₂ (triclinic, P1¯, Z = 2) were determined.     

New morpholine- and piperazine-functionalized triphenylantimony(V) catecholates: The spectroscopic and electrochemical studies

Novel functionalized triphenylantimony(V) catecholates - Ph₃Sb[4-O(CH₂CH₂)₂N-3,6-DBCat] (1), Ph₃Sb[4-PhN(CH₂CH₂)₂N-3,6-DBCat] (2), Ph₃Sb[4-Ph₂CHN(CH₂CH₂)₂N-3,6-DBCat] (3), Ph₃Sb[4,5-Piperaz-3,6-DBCat] (4) and binuclear bis-catecholate Ph₃Sb[3,6-DBCat-4-N(CH₂CH₂)₂N-4-3,6-DBCat]SbPh₃ (5) were synthesized by the oxidative addition reaction of corresponding o-quinones with triphenylantimony. The [4-O(CH₂CH₂)₂N-3,6-DBCat]²⁻, [4-PhN(CH₂CH₂)₂N-3,6-DBCat]²⁻, [4-Ph₂CHN(CH₂CH₂)₂N-3,6-DBCat]²⁻ and [4,5-Piperaz-3,6-DBCat]²⁻ are 4-(morpholin-1-yl)-, 4-(4-phenyl-piperazin-1-yl)-, 4-(4-dephenylmethyl-piperazin-1-yl)-, and 4,5-(piperazin-1,4-diyl)-3,6-di-tert-butyl-catecholate dianionic ligands, correspondingly. Complexes 1-5 were characterized in details by IR-, ¹H and ¹³C NMR spectroscopy and cyclic voltammometry. Molecular structure of 4·CH₃OH was determined by X-ray crystallography to be a distorted tetragonal-pyramidal. The NMR spectroscopic and electrochemical investigations of complexes in the presence of air reveal the reactions of complexes with dioxygen leading to the formation of spiroendoperoxides of 1,2,4,3-trioxastibolane type in a NMR yield of 25-37%.     

Ring-opening reactions of nonactivated aziridines catalyzed by tris(pentafluorophenyl)borane

The ring-opening reactions of nonactivated aziridines with amine nucleophiles are efficiently catalyzed by tris(pentafluorophenyl)borane leading to derivatives of trans-1,2-diamines in high yields. A mechanistic investigation of the reaction suggests that in situ formed [(C(6)F(5))(3)B(OH(2))].H(2)O catalyzes the opening through a Br?nsted acid manifold.     

Coulometric stripping potentiometry for arsenic(III)

Calibration-free determination of As^III in the presence of As^V using coulometric stripping potentiometry is described. As^III, in the concentration range 0.01-2 mg/L, is quantitatively reduced to elemental arsenic and simultaneously dissolved in gold codeposited onto a glassy carbon substrate by electrolysis for 4 minutes at −0.50 V (vs. Ag/AgCl (0.01 MCl⁻)) in 12 μL samples containing 3 M hydrochloric acid and 10 mg/L gold(III). Selectivity between arsenic(III) and (V) is achieved by proper control of the deposition potential and by minimizing the gold(III) concentration and the time between addition of gold(III) and commencement of analysis.     

Spectrophotometry Determination of Arsenic(III) and Antimony(III) by Means of Isonicotinoylhydrazones of 4-Dimethylaminobezaldehyde (4-Dbih) and 2-Hydroxynaphthaldehyde (2-Hnih)

Abstract

4-DBIH and 2-HNIH react with As(III) and Sb(III) respectively, in CH₃COOH medium to form colored complexes stable in presence of EDTA. As(III) and Sb(III) do not react with 2-HNIH and 4-DBIH respectively, and the Sb(III)-2-HNIH complex is extractable into isoamyl alcohol. These behaviours were used for the spectrophotometry determination of As (III) and Sb(III) in presence of several cations.     

The Structure of Tetrakis(pentafluorophenyl)tellurium(IV), Te(C6F5)4

Tetrakis(pentafluorophenyl)tellurium(IV), Te(C₆F₅)₄, was prepared from the reaction of TeCl₄ and Mg(C₆F₅)Br. Crystallization of the crude product from n‐pentane at ?25 °C gave suitable single crystals. The title compound crystallizes in the monoclinic space group P2₁/c (Z = 8) with two independent molecules per unit cell.     

The preparation of perfluoroalkenyl allenes (trienes) and pentafluorophenyl allenes

Trifluorovinyl- and (Z)-pentafluoropropenylcopper reagents readily react with propargylic halides or tosylates. With primary propargylic substrates, the major product is the alkyne. With secondary propargylic substrates, mixtures of alkyne/allene are obtained; the allene product is the major product. With tertiary propargylic substrates, the allene is regiospecifically and stereospecifically formed in good isolated yields. With pentafluorophenyl copper and primary propargylic substrates, the major product is pentafluorobenzene. With secondary and tertiary propargylic substrates, the allene is regiospecifically formed in good isolated yields.     

Synthesis and structures of tris(pentafluorophenyl)silylamines

Tris(pentafluorophenyl)silylamines were synthesized by silylation of amines and imines with (C₆F₅)₃SiCl or (C₆F₅)₃SiOTf in the presence of triethylamine. The crystal structures of the (C₆F₅)₃SiN(H)CH₂Ph and (C₆F₅)₃SiN(CH=CMe₂)CH₂Ph compounds were studied by X-ray diffraction. The crystal packings were analyzed by quantum chemical calculations in terms of the density functional theory (PBE exchange-correlation functional). Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1345–1352, July, 2007.     

Adsorption of antimony(III) and antimony(V) on bentonite: Kinetics, thermodynamics and anion competition

This research attempted to study the adsorption of Sb(III) and Sb(V) on bentonite using batch experiments. The effects of reaction time, temperature, initial Sb concentration, and competitive anions at different concentrations on the adsorption of Sb(III) and Sb(V) were investigated. Kinetic studies suggested that the adsorption equilibriums for both Sb(III) and Sb(V) were reached within 24 h. The desorption of Sb adsorbate on the bentonite was observed following Sb(III) adsorption, probably due to the oxidation of Sb(III) on the bentonite surface and subsequent desorption of Sb(V). In addition, oxidation of Sb(III) can occur in the solution medium also, which decreases the concentration of Sb(III) in the solution thereby driving the equilibrium in the direction of desorption from the surface. The adsorption data at three temperatures were successfully modeled using Langmuir (r² > 0.82) and Freundlich (r² > 0.99) isotherms. The thermodynamic parameters (ΔG⁰, ΔH⁰, and ΔS⁰) were calculated from the temperature dependence, suggesting that the adsorption process of Sb(III) is spontaneously exothermic, while the adsorption process of Sb(V) is spontaneously endothermic. Competitive anions such as , , and hardly affected the Sb(III) adsorption on bentonite, while and could compete with for adsorption sites. The competition between and on adsorption sites was presumably due to the formation of surface complexes and the surface accumulation or precipitation of on bentonite surface.