نتایج جستجو برای: ion pair mixed solvent
تعداد نتایج: 583769 فیلتر نتایج به سال:
For more than 30 years there has been an active and continued effort to develop synthetic receptors for anions and cations in organic solvents.1 We2 and others3 have shown that if both of the counterions in a target salt have localized charges then the consequent ion-pairing of the salt can dramatically lower receptor/ ion binding affinities and alter binding selectivities. One way to counter t...
In this work, the results relating to the mean activity coefficient measurements for ionic liquid of 1- propyl -3 methylimidazolium bromide, [PMIm]Br in ethanol+ water mixtures have been reported using potentiometric measurements at T=( 298.2, 308.2 and 318.2)K. The electromotive force (emf) measurements were performed on the galvanic cell of the type:Br-ISE│[PrMIm] (m) ethanol (wt.%), H2O (1−w...
The motions of solvent molecules during a chemical transformation often dictate both the dynamics and the outcome of solution-phase reactions. However, a microscopic picture of solvation dynamics is often obscured by the concerted motions of numerous solvent molecules that make up a condensed-phase environment. In this study, we use mixed quantum/classical molecular dynamics simulations to furn...
The separation of myo-inositol phosphates by ion pair, reverse-phase high performance liquid chromatography has been investigated. The retention of the inositol phosphates is dependent on both the polarity of the hetaeron utilized and on the pH of the solvent. A method is presented which permits the isocratic separation of multiple forms of inositol phosphates including isomers of myo-inositol ...
the complexation reactions between methylthymol blue (mtb) and co2+, ni2+, cu2+, zn2+ and pb2+ ions have been studied in different water-methanol mixtures at ph 4.45 and 25 °c by a spectrophotometric technique. the stepwise stability constants of the resulting 1:1 and 2:1 (metal ion to ligand) complexes were determined from the absorbance-mole ratio data. it was found that the overall stability...
The microsolvation of LiBO2 in water was investigated by conducting anion photoelectron spectroscopy and ab initio studies on the LiBO2(H2O)n(-) (n = 0-5) clusters. By comparing calculations with experiments, the structures of these clusters and their corresponding neutrals were assigned, and their structural evolutions were revealed. During the anionic structural evolution with n increasing to...
Solvent sublation has been studied for the separation and determination of trace iron(II) in various kinds of water samples. A strongly magenta-colored anionic [Fe(FZ)3](4-) complex was formed at pH 5.0 upon adding 3-(2-pyridyl)-5,6-bis(4-phenylsulfonic acid)-1,2,4-triazine (ferrozine, FZ) to the sample solution. Tetrabutylammonium bromide (TBAB) was added in the solution to form the (TBA)4[Fe(...
The results of a molecular dynamics (MD) computer simulation are presented for the solvation dynamics of an ion pair instanteously produced from a neutral pair, in a model polar aprotic solvent. These time-dependent fluorescence dynamics are analyzed theoretically to examine the validity of several linear response theory approaches, as well as of various theoretical descriptions (e.g., Langevin...
A simple extractive spectrophotometric method has been developed for the estimation of miconazole nitratein both pure and pharmaceutical preparation. The method is based on the formation of ion-pair complex of thedrug with acidic dye bromothymol blue (BTB) in acidic condition, followed by its extraction in organic solvent(chloroform). The absorbance was measured against the corresponding blank....
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