Nitrobenzene Phase Research Articles

On the complexation of some univalent cations with 1,3-alternate-25,27-bis(1-octyloxy)calix[4]arene-crown-6 in nitrobenzene saturated with water

From extraction experiments and c-activity measurements, the exchange extraction constants corresponding to the general equilibrium M (aq) ? 1 Cs (nb) , 1 M (nb) ? Cs (aq) taking place in the two-phase water–nitrobenzene system (M = Ag, K, Rb, Tl; 1 = 1,3-alternate-25,27-bis(1-octyloxy)calix[4]arene-crown6; aq is aqueous phase, nb is nitrobenzene phase) were determined. Moreover, the stability constants of the 1 M complexes in water-saturated nitrobenzene were calculated; they were found to increase in the series of K \ Rb \ Ag \ Tl.

Complexation of the lithium cation with beauvericin: Experimental and DFT study

From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Li+(aq)+1·Na+(nb)⇆1·Li+(nb)+Na+(aq) taking place in the two-phase water–nitrobenzene system (1=beauvericin; aq=aqueous phase, nb=nitrobenzene phase) was evaluated as logKex (Li+, 1·Na+)=0.5±0.1. Further, the stability constant of the 1·Li+ complex in nitrobenzene saturated with water was calculated for a temperature of 25°C as log βnb (1·Li+)=5.6±0.2. By using DFT calculations, the most probable structures of the non-hydrated 1·Li+ and hydrated 1·Li+·3H2O complex species were predicted.

Cooperative interaction of protonated hexamethylenetetramine with a hexaarylbenzene-based receptor: Experimental and theoretical study

► Stability constant of the HAB-based receptor complex with protonated hexamethylenetetramine was determined in nitrobenzene saturated with water. ► DFT was used. ► Structure of this complex was derived. From extraction experiments and γ -activity measurements, the extraction constant corresponding to the equilibrium HL + ( aq ) + 1 · Cs + ( nb ) ⇄ 1 · HL + ( nb ) + Cs + ( aq ) taking place in the two-phase water–nitrobenzene system (HL + = protonated hexamethylenetetramine, 1 = hexaarylbenzene-based receptor; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K ex (HL + , 1 ⋅Cs + ) = 0.5 ± 0.1. Further, the stability constant of the 1 ⋅HL + complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C as log β nb ( 1 ⋅HL + ) = 5.8 ± 0.2. Finally, by using quantum mechanical DFT calculations, the most probable structures A and B of the 1 ⋅HL + complex species, which are obviously in a dynamic equilibrium, were indicated. In both of these structures of the resulting complex 1 ⋅HL + having C 3 symmetry, the cation HL + synergistically interacts with the polar ethereal oxygen fence and with the central hydrophobic benzene bottom of the parent receptor 1 via cation–π interaction.

Controlling Cesium Cation Recognition via Cation Metathesis within an Ion Pair Receptor

Ion pair receptor 3 bearing an anion binding site and multiple cation binding sites has been synthesized and shown to function in a novel binding-release cycle that does not necessarily require displacement to effect release. The receptor forms stable complexes with the test cesium salts, CsCl and CsNO(3), in solution (10% methanol-d(4) in chloroform-d) as inferred from (1)H NMR spectroscopic analyses. The addition of KClO(4) to these cesium salt complexes leads to a novel type of cation metathesis in which the "exchanged" cations occupy different binding sites. Specifically, K(+) becomes bound at the expense of the Cs(+) cation initially present in the complex. Under liquid-liquid conditions, receptor 3 is able to extract CsNO(3) and CsCl from an aqueous D(2)O layer into nitrobenzene-d(5) as inferred from (1)H NMR spectroscopic analyses and radiotracer measurements. The Cs(+) cation of the CsNO(3) extracted into the nitrobenzene phase by receptor 3 may be released into the aqueous phase by contacting the loaded nitrobenzene phase with an aqueous KClO(4) solution. Additional exposure of the nitrobenzene layer to chloroform and water gives 3 in its uncomplexed, ion-free form. This allows receptor 3 to be recovered for subsequent use. Support for the underlying complexation chemistry came from single-crystal X-ray diffraction analyses and gas-phase energy-minimization studies.

Potential-Dependent Adsorption and Transfer of Poly(diallyldialkylammonium) Ions at the Nitrobenzene|Water Interface

Electrochemically driven adsorption and partition of a series of poly(diallyldialkylammonium) ions (PDADAA(+): alkyl = methyl, ethyl, propyl, and butyl) at the nitrobenzene (NB)|water (W) interface have been studied using voltammetry and electrocapillary measurements. When the phase-boundary potential, Δφ, that is, the inner potential of the W phase referred to that of the NB phase, is negative, poly(diallyldimethylammonium) (PDADMA(+)) shows little surface activity. The scanning of Δφ in the positive direction induces, first, the adsorption of PDADMA(+) at the interface and, then, the desorption of adsorbed PDADMA(+) ions into the NB phase, followed by the diffusion-limited transfer of PDADMA(+) from W to NB. The elongation of the dialkyl chains gives the stronger surface activity of PDADAA(+) even when Δφ < 0. The PDADAA(+) polyions studied are only slightly more hydrophilic than the corresponding monomers. However, the polycationic character of PDADAA(+) renders the adsorption, desorption, and ion transfer strongly dependent on Δφ and gives rise to unusual, M-shaped electrocapillary curves. The interplay of adsorption-desorption and ion transfer of PDADAA(+) ions induces the electrochemical instability of the interface and the emulsion formation on the NB side of the interface.

A Combined Experimental and Theoretical Study on the Complexation of Ag+ with a Hexaarylbenzene-Based Receptor

From extraction experiments and γ-activity measurements, the exchange extraction constant corresponding to the equilibrium Ag+(aq) + 1⋅Cs+(nb) ⇆ 1⋅Ag+(nb) + Cs+(aq) taking part in the two-phase water–nitrobenzene system (where 1 = hexaarylbenzene-based receptor; aq = aqueous phase, nb = nitrobenzene phase) was evaluated to be log 10Kex(Ag+, 1⋅Cs+) = −1.0±0.1. Further, the stability constant of the hexaarylbenzene-based receptor⋅Ag+ complex (abbreviation 1⋅Ag+) in nitrobenzene saturated with water, was calculated at a temperature of 25 °C: log 10βnb(1⋅Ag+) = 5.5±0.2. By using quantum mechanical DFT calculations, the most probable structure of the 1⋅Ag+ complex species was solved. In this complex having C3 symmetry, the cation Ag+ synergistically interacts with the polar ethereal oxygen fence and with the central hydrophobic benzene ring via cation–π interaction.

Extraction of some univalent cations into nitrobenzene by using a synergistic mixture of sodium dicarbollylcobaltate and barium ionophore I

From extraction experiments and c-activity measurements, the exchange extraction constants corresponding to the general equilibrium M (aq) ? 1 Na (nb) , 1 M (nb) ? Na (aq) taking place in the two-phase water–nitrobenzene system (M = Li, H3O , NH4 , Ag , K, Rb, Tl, Cs; 1 = barium ionophore I; aq = aqueous phase, nb = nitrobenzene phase) were determined. Furthermore, the stability constants of the 1 M complexes in water-saturated nitrobenzene were calculated; they were found to increase in the series of Cs \ Rb \ NH4 , K \ H3O ? \ Na \ Ag, Tl \ Li.

Voltammetric determination of concentrations of ferrocene-included nitrobenzene droplets in water

When a nitrobenzene (NB) phase came in quiescent contact with a water phase, water droplets were formed spontaneously near the oil|water interfaces (K. Aoki, M. Li, J. Chen, T. Nishiumi, Electrochem. Commn. 11 (2009) 239). We reported here quantitative data of the NB-droplets by use of UV-absorbance, dynamic light scattering (DLS) and voltammetry with a help of ferrocene. The supernatant separated spontaneously from the oil–water mixture contained 15.5 mmol dm −3 evaluated by UV spectra, whereas the centrifuged supernatant did 9.3 mM. The difference suggested the presence of NB-droplets, the diameter of which ranged 0.15–0.5 μm obtained by DLS. Ferrocene was dissolved deliberately in the aqueous solution and the NB solution up to saturation. The voltammograms in the ultrasonicated supernatant exhibited diffusion-controlled redox peaks of ferrocene, which should be supplied from both dissolved ferrocene and ferrocene-dissolved NB droplets. The former was 1/3.6 times of the latter by the comparison with the current of ferrocene-saturated aqueous solution. Applying the expression for the diffusion-controlled peak current of a big particle, we estimated the number concentration of NB droplet to be 1.1 × 10 14 dm −3. This value is equivalent to the average distance, L = 2.1 μm, between neighboring two droplets, corresponding to the diffusional traveling time, L 2/ D = 1.3 s, which would be long enough for collision of droplets to stabilize the emulsions.

Contribution to the Complexation of some Univalent Metal Cations with p-Tert-Butylcalix[4]arene-Tetrakis(N,N-Diethylacetamide) in Nitrobenzene Saturated with Water

Abstract From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+(aq)+NaL+(nb)⇔ML+(nb)+Na+(aq) taking place in the two-phase water-nitrobenzene system (M+=Li+, Ag+, Rb+, Tl+, Cs+; L=p-tert-butylcalix[4]arene-tetrakis(N,N-diethylacetamide); aq=aqueous phase, nb=nitrobenzene phase) were determined. Moreover, the stability constants of the ML+ complexes in water-saturated nitrobenzene were calculated; they were found to increase in the cation order Cs+ &lt; Rb+ &lt; Tl+ &lt; Ag+ &lt; Li+.

Synergistic extraction of some univalent cations into nitrobenzene by using sodium dicarbollylcobaltate and hexaethyl p-tert-butylcalix[6]arene hexaacetate

From extraction experiments and c-activity measurements, the exchange extraction constants corresponding to the general equilibrium M (aq) ? NaL (nb) , ML (nb) ? Na (aq) taking place in the twophase water–nitrobenzene system (M = H3O , NH4 þ, Ag, Tl; L = hexaethyl p-tert-butylcalix[6]arene hexaacetate; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Furthermore, the stability constants of the ML complexes in nitrobenzene saturated with water were calculated; they were found to increase in the following order: Agþ \ NH4 \ H3O \ Naþ \ Tlþ:

The growth of single crystal silver wires at the nitrobenzene|water interface

Single crystal silver wires can be grown at the nitrobenzene|water interface when silver ions dissolved in the aqueous phase are reduced by decamethyl ferrocene dissolved in the nitrobenzene phase. The successful growth of these wires depends on a number of experimental conditions, most prominently on the concentration ratio of reactants, nucleation rates, shape of formed nuclei, and wettability of nuclei. The size-time dependence can be modeled on the basis of microelectrode behavior of the silver nuclei and wire. AFM, SEM, light microscopy and single crystal X-ray diffraction has been applied to study the morphology of the silver nuclei and wires.

Protonation of Benzo-18-crown-6: Extraction and DFT Study

Abstract From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium H3O+(aq) + 1·Na+(nb)⇌1·H3O+(nb) + Na+(aq) taking place in the two-phase water-nitrobenzene system (1 = benzo-18-crown-6, aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K ex(H3O+, 1·Na+)=-0.8±0.1. Further, the stability constant of the 1·H3O+ complex in water-saturated nitrobenzene was calculated for a temperature of 25°C as log β nb(1·H3O+)=6.3±0.1. Finally, by using quantum mechanical DFT calculations, the most probable structure of the 1·H3O+ cationic complex species was derived. In this complex, the hydroxonium ion H3O+ is bound by three strong linear hydrogen bonds to one (Ar–O–CH2) ethereal oxygen and two (CH2–O–CH2) ethereal oxygen atoms of the parent crown ligand 1. The interaction energy was found to be -401.4kJ/mol, confirming the formation of the considered complex 1·H3O+.

Potentiometric determination of coextraction constants of potassium salts in ion-selective electrodes utilizing a nitrobenzene liquid membrane phase

A theoretical treatment of potentiometric data is applied to calculate coextraction constants ( K IA) for three potassium salts from water into a liquid nitrobenzene phase. The experiment involves treating nitrobenzene as a membrane and contacting it with two aqueous solutions of different ion activities. In the presence of either a cation or anion exchanger, the ratio of activities of ions in the two aqueous phases gives rise to a potential difference across the membrane that depends upon the nature and charge of the counter ion of the ion-exchanger in excess. Here, the cation exchanger was chosen to be potassium tetrakis(4-chlorophenyl)borate (KTpClPB) and the anion exchanger was tetradodecylammonium chloride (TDDACl). TDDACl was incrementally added to the nitrobenzene phase containing a fixed concentration of KTpClPB, and the corresponding emf was recorded as a function of concentration of TDDACl. The membrane changes from one with cation exchanger properties (excess KTpClPB) to one with anion exchanger properties (excess TDDACl). The potential difference and shape of the titration curve can be predicted by theory based on the phase boundary potential model. Log( K IA) values calculated for KCl, KNO 3 and KClO 4 in nitrobenzene were found as: −10.53 (± 0.09), −8.16 (± 0.05) and −5.63 (± 0.03) respectively, in accordance with the Hofmeister series of lipophilicity, and similar to those observed in PVC membranes containing other plasticizers. The method presented here offers the advantage over other methods to calculate K IA, in that it is relatively experimentally simple without compromising the accuracy of the calculated coextraction constants. The ability to titrate directly into the liquid membrane phase affords a higher precision compared to the preparation of a series of PVC/plasticizer membranes with different compositions.

Solvent extraction of some divalent metal cations into nitrobenzene by using a synergistic mixture of strontium dicarbollylcobaltate and hexaethyl calix[6]arene hexaacetate

From extraction experiments and c-activity measurements, the exchange extraction constants corresponding to the general equilibrium M2þðaqÞ þ SrL2þðnbÞ , ML2þðnbÞ þ Sr2þðaqÞ taking place in the two-phase water–nitrobenzene system (M = Ca, Ba, Pb, Cd; L = hexaethyl calix[6]arene hexaacetate; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Moreover, the stability constants of the ML complexes in nitrobenzene saturated with water were calculated; they were found to increase in the following order: Cd \ Ca \ Sr \ Pb \ Ba.

Solvent extraction of H3O+, NH4 +, Ag+, K+, Rb+ and Tl+ into nitrobenzene by using cesium dicarbollylcobaltate in the presence of a hexaarylbenzene-based receptor

From extraction experiments and γ-activity measurements, the extraction constants corresponding to the general equilibrium M+(aq) + 1·Cs+(nb) \( \rightleftarrows \)1·M+(nb) + Cs+(aq) taking part in the two-phase water–nitrobenzene system (1 = hexaarylbenzene-based receptor; M+ = H3O+, NH4+, Ag+, K+, Rb+, Tl+; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Furthermore, the stability constants of the ML+ complex species in nitrobenzene saturated with water were calculated; they were found to increase in the series of Rb+ < K+ < Ag+, Tl+ < H3O+, NH4+.

Solvent extraction of europium trifluoromethanesulfonate into nitrobenzene in the presence of p-tert-butylcalix[6]arene and p-tert-butylcalix[8]arene

From extraction experiments and γ-activity measurements, the extraction constants corresponding to the general equilibrium Eu3+(aq) + 3A−(aq) + L(nb) ⇔ EuL3+(nb) + 3A−(nb) taking part in the two-phase water–nitrobenzene system (A− = CF3SO3−; L = p-tert-butylcalix[6]arene, p-tert-butylcalix[8]arene; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Further, the stability constants of the EuL3+ complexes in nitrobenzene saturated with water were calculated for a temperature of 25 °C as log βnb(EuL3+) = 6.4 ± 0.1 (L = p-tert-butylcalix[6]arene) and log βnb(EuL3+) = 11.3 ± 0.1 (L = p-tert-butylcalix[8]arene).

Individual extraction constants of some organic cations in the two-phase water–nitrobenzene system

From extraction experiments and c-activity measurements, the exchange extraction constants corre- sponding to the general equilibrium C ? (aq) ? Cs ? (nb) , C ? (nb) ? Cs ? (aq) taking part in the two-phase water- nitrobenzene system (C ? = organic cation; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Further- more, the individual extraction constants of 15 organic cations in the mentioned two-phase system were calculated.

Experimental and DFT study on the complexation of [formula omitted] with a hexaarylbenzene-based receptor

From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium NH 4 + ( aq ) + 1 · Cs + ( nb ) ⇆ 1 · NH 4 + ( nb ) + Cs + ( aq ) taking part in the two-phase water–nitrobenzene system ( 1 = hexaarylbenzene-based receptor; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K ex ( NH 4 + , 1 · Cs + ) = - 0.4 ± 0.1 . Further, the stability constant of the 1 · NH 4 + complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C as log β nb ( 1 · NH 4 + ) = 6.3 ± 0.2 . By using quantum mechanical DFT calculations, the most probable structures A and B of the 1 · NH 4 + complex species, which are obviously in a dynamic equilibrium, were indicated. In both of these structures of the resulting complex 1 · NH 4 + having C 3 symmetry, the cation NH 4 + synergistically interacts with the polar ethereal oxygen fence and with the central hydrophobic benzene bottom via cation– π interaction.

Extraction and DFT study on the complexation of the cesium cation with a hexaarylbenzene-based receptor

Abstract From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Cs+(aq) + A−(aq) + 1(nb) ⇆ 1·Cs+(nb) + A− (nb) taking part in the two-phase water–nitrobenzene system (A− = picrate, 1 = hexaarylbenzene-based receptor; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K ex (1·Cs+, A−) = 2.8 ± 0.1. Further, the stability constant of the hexaarylbenzene-based receptor·Cs+ complex (abbrev. 1·Cs+) in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log β nb (1·Cs+) = 4.7 ± 0.1. By using quantum mechanical DFT calculations, the most probable structure of the 1·Cs+ complex species was solved. In this complex having C 3 symmetry, the cation Cs+ synergistically interacts with the polar ethereal oxygen fence and with the central hydrophobic benzene bottom via cation–π interaction. Finally, the calculated binding energy of the resulting complex 1·Cs+ is −220.0 kJ/mol, confirming relatively high stability of the con...

Individual extraction constants of some divalent metal cations in the two-phase water–nitrobenzene system

From extraction experiments and c-activity measurements, the exchange extraction constants corresponding to the general equilibrium M(aq) ? Sr(nb) ¢ M(nb) ? Sr(aq) taking part in the two-phase water– nitrobenzene system (M = Mg, Ca, Ba, Cu, Zn, Cd, Pb, UO2þ 2 , Mn , Fe, Co, Ni; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Furthermore, the individual extraction constants of the M cations in the mentioned two-phase system were calculated; they were found to increase in the following cation order: UO2þ 2 \ Zn , Ni \ Cu, Cd \ Co \ Mg \ Ca \ Mn, Fe \ Sr \ Pb \ Ba.