Tetraphenylborate Ion Research Articles

Viscosities of Some Tetraalkylammonium and Alkali-Metal Salts in N, N-Dimethylacetamide at 25 - C

The viscosities of solutions of tetrapropylammonium bromide (Pr4NBr), tetrabutylammonium bromide (Bu4NBr), tetrapentylammonium bromide (Pen4NBr), tetrahexylammonium bromide (Hex4NBr), tetraheptylammonium bromide (Hep4NBr), tetraoctylammonium bromide (Oct4NBr), tetrabutylammonium tetraphenylborate (Bu4NBPh4), sodium tetraphenylborate (NaBPh4), and potassium tetraphenylborate (KBPh4) in N,N-dimethylacetamide are reported at 25°C. The viscosity data havebeen analyzed by the Jones-Dole equation for associated electrolytes to evaluate the viscosity B coefficients of the electrolytes. These data have also been analyzed by the transition-state theory to obtain the contribution of the solutes to the free energy of activation for viscous flow of the solution. The ionic contribution to the viscosity B coefficient and the free energy of activation for viscous flow have been estimated using of the “reference electrolyte” Bu4NBPh4. The bromide, tetraphenylborate, and tetraalkylammonium ions are found to be weakly solvated in N,N-dimethylacetamide, whereas significant solvation has been detected for sodium and potassium ions. The viscosity of the solvent is greatly modified by the presence of all the ions investigated here with the exception of the bromide ion.

Modified Potentiometric Sensors for the Separate Determination of Cationic Surfactants

The main electrochemical and performance characteristics of solid-contact sensors for cationic surfactants based on an organic cetylpyridinium–tetraphenylborate ion exchanger were determined. It was found that the surface of the sensors for cationic surfactants can be modified with poly(vinyl chloride) molecular sieves. The modified electrodes can separately determine alkylpyridinium homologues with different lengths of hydrocarbon radicals (C10–C18).

Electrochemical Synthesis of Tetraphenylborate Doped Polypyrrole and Its Applications in Designing a Novel Zinc and Potassium Ion Sensor

The electrochemical synthesis of tetraphenylborate (TPB) ion doped polypyrrole is reported. The electrochemical polymerization of ion exchanger doped polypyrrole is carried out in dry acetonitrile. The polypyrrole synthesized under present conditions is characterized by scanning electron microscopy and cyclic voltammetry. The applications of new ion exchanger doped polypyrrole in the development of solid-state ion sensors are reported. The ion sensing properties and construction of new conducting polymer based Zn++ ion and potassium ion sensors are described. The Zn++ ion sensor is developed by TPB doped polymer modified electrode itself whereas K+ ion sensor is developed by laying down of another layer of dibenzo-18-crown-6 impregnated plasticized Polyvinylchloride (PVC) matrix membrane. The response curve on Zn++ ion sensing with and without polymer layer is also studied and reported. An effort on selective sensing of Zn++ ion is also made and the data on Ni++, Co++, Pb++, and Mg++ ions are reported using polymer modified electrode. Similarly the effect of Na+ and NH ions on the response of K+ ion sensing is also reported. The contribution of tetraphenylborate in designing these ions sensors are discussed.

The electrooxidation of the tetraphenylborate ion revisited

The electrochemistry of the tetraphenylborate ion, BPh4−, has been studied by cyclic voltammetry and coulometry in water, methanol, ethanol, acetonitrile, acetone, dimethylformamide and dichloromethane under an N2 atmosphere. While a one-electron and somewhat irreversible oxidation (with an E1/2 of 0.87 V vs. SCE at a glassy carbon electrode) is observed in dichloromethane, eqn. (i), the oxidation is somewhat complicated in all other solvents by the occurrence of several consecutive reactions. Epa, the anodic peak potential in cyclic voltammetry, changes from 0.41 V vs. SCE in water to 0.94 V vs. SCE in dimethylformamide at a glassy carbon electrode. The variation in Epa with solvent (S) is explained by invoking reaction (ii). The coulometric results in solvents other than dichloromethane indicate a disproportionation of S–BPh3, eqn. (iii).

A NOVEL 8-HYDROXYQUINOLINE PVC COATED GRAPHITE SENSOR FOR POTENTIOMETRIC DETERMINATION OF SOME METAL IONS

ABSTRACT A novel potentiometric 8-hydroxyquinoline PVC coated graphite sensor incorporating 8-hydroxyquinoline (oxine)–tetraphenylborate (TPB) ion pair as an electroactive material and dioctylphthalate (DOP) as a solvent mediator is described and electrochemically evaluated. The proposed sensor exhibits fast Nernstian response for 8-hydroxyquinoline over the concentration range 10−6–10−1 mol L−1 with a cationic calibration slope of 59.0 ± 0.5 mV/concentration decade and a detection limit of 4 × 10−7 mol L−1 (0.05 ppm). Interferences from common inorganic cations are negligible. The sensor is successfully used for monitoring titration of some metal ions (e.g., Cu2+, , Cd2+, Ca2+, , Co2+, Ni2+, Zn2+, Th4+, and Pb2+) with 8-hydroxyquinoline titrant at suitable pH values. Some metal ions (e.g., Cu2+) are determined in presence of many common metal ions without interference. The average recoveries of the tested metal ions ranged from 95–98 ± 1% and a mean standard deviation is 1.8%.

Trace analysis of γ-cyclodextrin in a sample of β-cyclodextrin by capillary electrophoresis

A new capillary electrophoretic method for trace analysis of γ-cyclodextrin, γ-CD, in a sample of β-CD has been developed, building on our recent work in which the tetraphenylborate ion, Ph 4B −, was found to bind to γ-CD three orders of magnitude more strongly than to β-CD. The method involves measurement of the change of net electrophoretic mobility of Ph 4B − and its CD complexes in a background electrolyte containing a fixed concentration of β-CD. Good linearity was found between 1/Δ μ and 1/ C γ, where Δ μ is the difference in the mobility of Ph 4B − in the β-CD solution at a given and at zero concentration of γ-CD, and C γ the γ-CD concentration. The limit of detection for γ-CD in a β-CD sample was found to be 0.020% (w/w), and high precision and accuracy were obtained.

Comparison of binding of tetraphenylborate and tetraphenylphosphonium ions to cyclodextrins studied by capillary electrophoresis

Comparison of binding of tetraphenylborate and tetraphenylphosphonium ions to cyclodextrins studied by capillary electrophoresis

Ion-Selective Electrodes for the Determination of Nitrogen-Containing Medicinal Substances

Stoichiometric ratios and solubility products were determined for medicinal substance–tetraphenyl borate ion pairs. The influence of the nature of the medicinal substance cation incorporated into ionophores and the effect of the solvent–plasticizer on analytical characteristics were studied. The optimal composition of membranes was determined. Ion selective electrodes were used for the potentiometric determination of dimedrol, papaverine, novocaine, and lidocaine in medicinal forms.

Determination of Cremophor EL in plasma after sample preparation with solid phase extraction and plasma protein precipitation.

The non-ionic emulsifier Cremophor EL can be quantified using a special potentiometric titration technique with barium chloride activation and precipitation with sodium tetraphenylborate. The end point of the titration is indicated by an ionsensitive coated wire electrode which responds to an excess of tetraphenylborate ions. Sample preparation is necessary to quantify the excipient in plasma of patients receiving ciclosporin formulations with Cremophor EL (Sandimmun), since plasma proteins cause disturbances of the titration. Solid phase extraction was tested with various sorbent materials. Although some of the sorbents yielded good extraction rates of Cremophor EL from aqueous solutions, the extraction rates from plasma were significantly lower. Therefore, plasma protein precipitation with acetonitrile has been examined as an alternative to SPE and has been proved the superior method. Using the precipitation technique, a recovery rate of above 90% was achieved. Furthermore, the limit of detection from plasma was found to be 30 microg, in analogy to the determination from aqueous solutions. The combination of the plasma protein precipitation with the potentiometric titration allows quantitation and thus pharmakokinetic investigations of Cremophor EL in patients treated with Sandimmun after kidney-transplantation.

Thermodynamics of Ion Association and Solvation in 2-Methoxyethanol: Behavior of Tetraphenylarsonium, Picrate, and Tetraphenylborate Ions from Conductivity and Ultrasonic Data

Precise measurements on electrical conductances and ultrasonic velocities of solutions of potassium picrate (KPic), potassium tetraphenylborate (KBPh4), tetrabutylammonium tetraphenylborate (Bu4NBP...

New fluorescent quinolinium dyes — applications in nanometre particle sizing

Bromide, iodide and tetraphenylborate quaternary salts of four new highly fluorescent dyes have been produced by the reaction of the 6-methoxyquinoline heterocyclic nitrogen base with 3-bromo-1-propanol, methyl iodide and methyl bromide with one of the dyes having its counter-ion exchanged for the tetraphenylborate ion. Three of the dyes, unlike the base, are readily water soluble, the tetraphenylborate salt only slightly water soluble and all are fluorescent over a broad pH range. The dyes have been characterised in terms of their water solubility, their steady-state fluorescence spectra and their bi-exponential fluorescence lifetimes, which are all found to be in the range ≈ 10–30 ns. We have found that the cationic dyes readily bind to negatively charged colloidal silica particles and because of the suitably long fluorescence lifetimes we have been able to determine the particle size of Du Pont's SM30 colloidal silica using time-resolved fluorescence anisotropy. The average particle diameter, determined using three of the dyes, was 6.8 ± 0.6 nm, which compares well with Du Pont's mean value of 7 nm.

New indolium and quinolinium dyes sensitive to aqueous halide ions at physiological concentrations

AbstractTwelve new highly fluorescent dyes have been produced by the reaction of two heterocyclic nitrogen bases with 8‐bromooctanoic acid, 11‐bromoundecanoic acid and 15‐bromopentadecanoic acid. The bromide counter ions of the first six dyes have been replaced with the tetraphenylborate ion. Unlike the bases themselves, the quaternary salts are water soluble and have fluorescence characteristics independent of pH in the pH range 7–11. Both the fluorescence intensity and fluorescence lifetime of dyes 1–12 are reduced in the presence of aqueous halide ions allowing halide concentrations to be determined accurately at physiological levels. All the dyes have been characterised in terms of steady state fluorescence spectra and steady‐state Stern‐Volmer analysis.

Isolation of Protonated Arenes (Wheland Intermediates) with BArF and Carborane Anions. A Novel Crystalline Superacid

Isolation of Protonated Arenes (Wheland Intermediates) with BAr^F and Carborane Anions. A Novel Crystalline Superacid

Flow injection determination of cationic polyelectrolytes using a tetraphenylborate-selective electrode detector.

A potentiometric flow injection determination method for cationic polyelectrolytes utilizing a flow-through-type tetraphenylborate-selective electrode detector is described. The method is based on detecting any concentration decrease of the tetraphenylborate ion by the formation of an ion associate between cationic polyelectrolyte, poly(diallyldimethylammonium chloride) (Cat-floc) and tetraphenylborate ion. The response of the electrode detector, as a peak-shaped signal, was obtained for injected cationic polyelectrolyte samples. A linear relationship was found to exist between the peak height and the logarithmic concentration of Cat-floc with a slope of 17 mV/decade over a concentration range of 5 × 10 -5 to 1 × 10 -3 mol l-1. The detection limit for Cat-floc was 1 × 10 -5 mol l-1. The sampling rate was ca. 12 samples/h.

Impedance spectroscopic investigation of the temperature influence on the transfer of tetraphenylborate ions through lipid membranes — Calculation of energy barriers for the ion transfer across lipid membranes

Investigating the transfer of tetraphenylborate (TPB) ions through planar lipid membranes we found a strong influence of temperature on the impedance spectrum. The impedance spectrum of TPB modified lipid membranes is governed by two processes, namely, the ion transfer at the membrane surfaces and the ion transfer across the hydrophobic interior of the membrane. The analysis of the measured spectra showed that temperature predominately influences the inner ion transfer and the rate constant for the inner transfer, respectively. We used this temperature dependence to calculate energy barriers for the ion translocation across the membrane interior. Varying the composition of the membrane lipids we found that the inner barrier not only depends on the hydrocarbon part but also on the head group of the lipid. We explain this interesting result with interactions of the permeating TPB ions with the head groups of the membrane. The above-mentioned interactions seem to immobilize the TPB ion at the membrane surface and to enlarge the energy barrier for the ion transfer across the inner part of the lipid membrane. The largest barriers were found for the investigated lecithins whose phosphocholine head group strongly interacts with the TPB ions.

Preconcentration of trace cobalt with the ion pair of 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol and tetraphenylborate onto microcrystalline naphthalene or column method and its determination by derivative spectrophotometry

Cobalt-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP)-tetraphenylborate ion associated complex is quantitatively adsorbed on microcrystalline naphthalene in the pH range 3.5–9.5 from a fairly large volume of the aqueous samples (preconcentration factor ~30). After filtration, the solid mass consisting of the cobalt complex and naphthalene was dissolved with 5 ml of dimethylformamide (DMF) and the metal determined by first-derivative spectrophotometry. The cobalt-5-Br-PADAP complex can alternatively be quantitatively retained on ammonium tetraphenylborate-naphthalene adsorbent filled in a column (preconcentration factor 120) in the same pH range and determined similarly. The detection limit is 30 ppb (signal-to-noise ratio=2) and the calibration curve is linear over 0.3–8.0 μg of cobalt in 5 ml of the final DMF solution. Eight replicate determinations of 1.0 μg of cobalt gave a mean peak height of 0.208 (at 611.5 nm) with a relative standard deviation of 1.2%. The sensitivity of the method is 1.04 (d A/d nm) ml μg −1 found from the slope of the calibration curve. The interference of a large number of anions and cations on the determination of cobalt has been studied and the optimized conditions developed were utilized for its trace determination in various standard alloys and biological samples.

Environmentally acceptable nuclear fuel cycle development of a new reprocessing system

The aim of the present study is to establish a new reprocessing system for spent nuclear fuel, which would overcome the environmental problems in the nuclear fuel cycle. In order to achieve this, the following subjects have to be conquered: recoveries of high ratios of uranium and trans uranium elements from spent nuclear fuel, separations of strong radioactive elements, such as Sr and Cs, and assurance of the extreme safety during operation. The last subjects might be of particular importance in order to avoid any potential danger. Therefore, in the present system all processes were performed under mild aqueous conditions. Experiments were carried out for a simulated spent fuel solution, which was calculated from the ORIGEN CODE containing uranium and 17 major elements. The system consists of the following processes: 1. dissolution of spent UO 2 fuel involving off-gas treatment of I and Ru; 2. neutralization of the dissolved fuel solution with NaHCO 3Na 2CO 3 mixed solution to be slightly basic at pH about 9 followed by the separation of precipitated fission products by centrifugation; 3. separation of Cs by a precipitation method using tetraphenylborate ion; 4. recovery of U, Np and Pu as precipitates of hydrolyzed compounds from alkaline solution; 5. separation of Am and Cm from lanthanide elements. The concentration of residual uranium in the final solution was measured to be ppm order, indicating that the decontamination factor of U was as large as 10 4. Other hexa-valent actinide ions, NpO 2 2+ and PuO 2 2+, also have extremely large stability constants for the complex formation with carbonate ion, and are expected to behave similarly with UO 2 2+. In conclusion, the present reprocessing system enables us to recover U, Pu and Np from spent nuclear fuel by means of a simple precipitation method in much higher ratios compared with other reprocessing methods, to separate hazardous Cs and Sr from high-level waste, and to exclude any potential danger owing to chemical processes under mild aqueous conditions.

Study on a Nuclear Fuel Reprocessing System Based on the Precipitation Method in Mild Aqueous Solutions

A new reprocessing system for spent nuclear fuels based on a precipitation method is proposed to recover uranium and transuranium elements from spent nuclear fuels in high ratios and to achieve extreme safety without any potential dangers. Experiments were carried out for a simulated fuel solution containing uranium and 17 major elements. The main reprocessing processes are as follows: (a) dissolution of U02 fuel under mild conditions; (b) neutralization of the dissolved fuel solution with Na2C03-NaHC03 mixed solutions, followed by the separation of precipitated fission products by centrifugation; (c) separation of cesium by a precipitation method using a tetraphenylborate ion; and (d) recovery of uranium (U) as a precipitate of the hydrolyzed compound from an alkaline solution. As a result, 99.95% of the U was recovered with the least amount of fission products, i.e., 10-5 g or even less in the recovered 1 g of U with the only exceptions being zirconium and molybdenum.

Hydration of Ions in Organic Solvent and Its Significance in the Gibbs Energy of Ion Transfer between Two Immiscible Liquids

Various kinds of cations (alkali and alkaline earth metal ions, Me4N+, Et4N+, n-Bu4N+, and tetraphenylarsonium ion) and anions (halide ions, SCN-, ClO4-, NO3-, and tetraphenylborate ion) have been extracted from water to nitrobenzene (NB) using several extractants: viz. tetraphenylborate and dipicrylaminate for the cations; n-Bu4N+, n-Pen4N+, n-Hep4N+, and tris(1,10-phenanthroline)iron(II) for the anions. The determination of water content in NB by means of the Karl Fischer method has confirmed that some water molecules are coextracted by hydrophilic inorganic cations and anions. Accurate numbers (n) of the coextracted water molecules per ion have been established. On the basis of these findings, a new model has been proposed for a better understanding of the Gibbs energy of ion transfer at the organic solvent/water interface. If hydrated radii of ions evaluated from n are used, conventional (Born-type) electrostatic solvation models are invalid. A new approach recognizing short-range ion−solvent interactions (e.g. hydrogen bonds) has given a better account of for the hydrated ions.

Effect of tetraphenylphosphonium and tetraphenylborate ions on the water structure in aqueous solutions; FTIR studies of HDO spectra

FTIR spectroscopy has been used to study interactions of Ph4B- and Ph4P+ ions with water in aqueous solutions. The effect of Ph4BNa and Ph4PCl on the HDO vibration band in the fundamental region has been investigated. A new modification of the difference spectra method has been applied for the analysis of the spectral data. The results have revealed distinct differences in hydration of Ph4B- and Ph4P+ ions: Ph4B- ion strongly decreases the hydrogen-bond energy of surrounding water molecules, while Ph4P+ ion changes it slightly. The effect of Ph4B- is determined by anion–water interactions, while the effect of Ph4P+ is determined by water–water interactions around the cation. The changes in the energy of water hydrogen bonds upon the ions have been evaluated.