Borate , Tetraphenyl

BNC,(,H22, Boron, diethyl- -propyny tri-methylamineK 29 77 BNgPjCjgHjg, Borate —), tetraphenyl-, l,l,l,3,3,3-hexakis dimethylamino)tri-phosphenium, 27 256... 

Blomstrand-Jprgensen chain theory, 6 Borate, tetraphenyl-in gravimetry, 534 Bridge groups, 22 Briggs, Samuel Henry Clifford, 14 Bromates... 

Table 5-1. Enantioselectivities determined for several drugs. All experiments were performed at room temperature, except those marked with, which were performed at 4 °C. In some cases a lipophilic anion was used to facilitate the solubilization of the drug in the organic phases (PFj = hexafluorophosphate BPh = tetraphenyl borate). DHT = dihexyl tartrate DBT = dibenzoyl tartrate PLA = poly (lactic acid). ...

Discussion. Potassium may be precipitated with excess of sodium tetraphenyl-borate solution as potassium tetraphenylborate. The excess of reagent is determined by titration with mercury(II) nitrate solution. The indicator consists of a mixture of iron(III) nitrate and dilute sodium thiocyanate solution. The end-point is revealed by the decolorisation of the iron(III)-thiocyanate complex due to the formation of the colourless mercury(II) thiocyanate. The reaction between mercury( II) nitrate and sodium tetraphenylborate under the experimental conditions used is not quite stoichiometric hence it is necessary to determine the volume in mL of Hg(N03)2 solution equivalent to 1 mL of a NaB(C6H5)4 solution. Halides must be absent. 

The standard Gibbs energy of electrolyte transfer is then obtained as the difference AG° x ° = AG° ° - AG° x. To estabfish the absolute scale of the standard Gibbs energies of ion transfer or ion transfer potentials, an extrathermodynamic hypothesis must be introduced. For example, for the salt tetraphenylarsonium tetraphenyl-borate (TPAs TPB ) it is assumed that the standard Gibbs energies of transfer of its ions are equal. 

Fig. 18a. 10. Chemical structures of ion exchangers used in polymeric membranes of ion-selective electrodes with preference toward ions as indicated, (a) Tetraphenyl borates anion exchanger, (b) tridodecyl methyl ammonium chloride cation exchanger and (c) newly introduced carborane cation exchanger.

The present author has developed a novel method called ion-association method. This is also a simple and versatile method for the preparation of ion-based organic dye nanoparticles in pure aqueous solution by the ion association approach [23]. It utilizes the control of hydrophilicity/hydrophobicity of the ionic material itself via ion-pair formation for example, addition of a cationic target dye solution into aqueous solution containing a certain kind of hydrophobic anions forms an electrically neutral ion-pair because of the strong electrostatic attraction, followed by aggregation of ion-pair species originated from van der Waals attractive interactions between them to produce nuclei and the subsequent nanoparticles (Fig. 3). In this case, hydrophobic but water-soluble anions, such as tetraphenyl-borate (TPB) or its derivatives (tetrakis(4-fluorophenyl)borate (TFPB), tetrakis [3,5-... 

Materials Required Benzethonium chloride 0.15 g Chloroform 50 ml bromophenol blue solution (Dissolve with heating 0.2 g of bromophenol blue in 3 ml of 0.1 M NaOH and 10 ml of ethanol (96%). Allow to cool and dilute to 100 ml with ethanol 96%] 50 ml sodium tetraphenyl borate solution (1% w/v in chloroform) 50 ml sintered-glass crucible No 4. 

Fig. 3.4. Hydrophobic anion effect on ise- The membrane contains valinomycin with equivalent concentration of potassium tetraphenyl-borate dissolved in 2-nitro-p-cymene. - ise dependence on the activity of KCl o - f jgg dependence on the activity of KCIO4. The curves were calculated using equation (3.3.13). (After W. E. Morf, G. Kahr and W. Simon.)...

A mixture consisting of 25 mL of an aqueous (0.2 to 1.0 mM) solution of chlorpromazine hydrochloride and 5 mL of 0.1 M acetate buffer (pH 3.3) was titrated to a potentiometric endpoint with 0.0 IM sodium tetraphenyl-borate [77]. The titrant was added at a rate of 0.36 mL/min with continuous stirring, and the temperature of the medium was maintained at 22 2°C. The end point was detected by a tetraphenylborate-selective electrode. 

AIBN2O4C64H82, Aluminum, bisftetrahydro furan)-l,2-bis(2-hydroxy-3,5-bis(tcrt-butyl)-benzylideneimino)ethane-, tetraphenyl borate, 34 19... 

I think that we do not understand specificity very well. We should remember the importance of anion polarizability and we should not lose sight of peculiar cases such as the precipitation of potassium tetraphenyl borate, K+(Bcf>4). ... 

Some neighbors are aliphatic groups. When describing selectivity of ionic reactions we must remember that potassium tetraphenyl borate is insoluble. There are no large oriented dipoles near to the potassium. 

Crown-ether network polymers have also been prepared by adding to a slurry of NaH in THF, an equimolar amount of the appropriate hydroxy-containing crown-ethers followed by the addition of chloromethylated cross-linked polystyrene. Binding of Na, K, Cs picrates and of sodium tetraphenyl-borate to the immobilized crown-ether is achieved under simple conditions [74]. 

Phosphonium salts, which are generally stable in the form of iodide and tetraphenyl-borate crystalline solids, are frequently purified by recrystallization. Where this is not possible, thick-layer chromatography (0.2-1 mm Kieselguhr, silica) may afford a satisfactory method of purification12,13. In this manner, analysis using secondary ion mass spectrometry (SIMS) has a detection limit 10-50 ng per spot14. 

Chloride monohydrate. Tetraphenyl borate. c Bromide pentahydrate. 

In comparison, the l,3-dialkylimidazolium-2-carboxylate isolated by Tommasi et al. [27, 40] was revealed to be a more versatile catalyst that allowed the synthesis of benzoylacetic acid from benzophenone and C02 in good yield and under mild conditions (isolated yield 81%). The presence of tetrafluoroborate- or tetraphenyl-borate sodium salts in the reaction was essential, as this allowed the formation of the related 1,3-dialkylimidazolium tetrafluoroborate or tetraphenylborate and the concomitant quantitative trans-carboxylation to sodium benzoylacetate. Likewise, compounds such as acetone, cyclohexanone, and phenylacetonitrile could also be converted with this system to afford the corresponding carboxylate salts (methyl a-cyanophenylacetate) (Scheme 5.8). Following the same general procedure, acetone was carboxylated, being simultaneously the cosolvent and reagent. 

The construction and electrochemical response characteristics of poly (vinyl chloride) membrane sensors for donepezil HC1 are described. The sensing membranes incorporate ion association complexes of donepezil HC1 cation and sodium tetraphenyl borate (sensor 1), or phospho-molybdic acid (PMA) (sensor 2), or phosphotungstic acid (sensor 3) as electroactive materials. The sensors display a fast, stable, and near-Nemstian response over a relative wide donepezil HC1 concentration... 

Paper partition chromatographic methods have been widely applied to the analysis of tetracyclines (128, 129). Pharmaceutical aqueous suspensions for oral use are acidified with HC1 and diluted with methanol. Crystalline formulations are dissolved only in methanol. A paper chromatographic method for TC determination in pharmaceutical preparations is based on the complexation of the antibiotic with a mixture of urea and disodium edetate on paper at pH 7.4. Urea helped in the separation of degradation products and led to the formation of well defined spots (130). Samples from fermentations must be acidified with oxalic acid to liberate TC from the mycelium. TC in filtrates may be precipitated in saturated solution of sodium tetraphenyl borate, precipitate dissolved in ethyl or butyl acetate and applied for paper chromatography. Various solvent systems and hRp values for paper chromatography are given in Table 4. 

Quercetin-sodium tetraphenylborate A mixture of quercetin (0.015% in methanol) and sodium tetraphenyl-borate (1% in n-butanol saturated with water) is sprayed on the plate to yield orange/red spots. 

The piperidine derivative (111) has been reported109 from the reaction of piperidine and 112 in acetic acid with sodium tetraphenyl-borate. The piperidine derivative (113) arises from a displacement of... 

Khalil and El-Aliem constructed a coated-wire benazepril-selective electrode based on incorporation of the benazepril-tetraphenyl borate ion pair in a poly (vinyl chloride) coating membrane [13]. The influence of membrane composition, temperature, pH of the test solution, and foreign ions on the electrode performance was investigated. At 25° C, the electrode showed a Nernstian response over a benazepril concentration... 

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