Tetraphenylarsonium Tetraphenylborate Research Articles

The heat capacity and density of solutions of barium and tetrabutylammonium iodides in N-methylpyrrolidone at 298.15 K

The heat capacity and density of solutions of barium and tetrabutylammonium iodides in N-methylpyrrolidone (MP) were studied at 298.15 K by calorimetry and densimetry. The standard partial molar heat capacities and volumes ( $$ \overline {C_{p^2 }^ \circ } $$ and $$ \overline {V_2^ \circ } $$ ) of the electrolytes in MP were calculated. The standard heat capacities $$ \overline {C_{pi}^ \circ } $$ and volumes $$ \overline {V_i^ \circ } $$ of the Ba2+ and (C4H9)4N+ ions in solution in MP at 298.15 K were determined. With the tetrabutylammonium ion, these values were in agreement with those calculated on the basis of the tetraphenylarsonium-tetraphenyl borate and tetraphenylphosphonium-tetraphenyl borate assumptions. The results are discussed in relation to the special features of solvation in solutions of the salts studied.

ΔS°t – as a Structural Probe – a Critical Analysis of the Method and Determination of Structure of Aquo-Alcoholic Mixtures

Abstract Attempts were made for a critical examination of the use of ΔS°t as a structural probe to study the ion induced perturbations on aquo-alcoholic solvent mixtures. The division of the thermodynamic properties of TATB (tetraphenyl arsonium tetraphenyl borate) in solution into equal parts is not free from defects. Naturally, the calculation of single ion values based on TATB is also problematic. Dissection of the single ion values like TΔS°t(ion) as suggested by Kundu is full of errors. Analysis shows TΔS°t(ion) to be an insensitive parameter to determine the structural characteristics of aquo-alcoholic mixtures. Structure of aquo-alcoholic mixtures should be determined from the excess thermodynamic properties of mixing, excess dielectric properties of mixing, excess polarizabilities, the correlation parameter “g” etc. Other properties like ultrasonic sound absorption, excess volume and viscosity of mixing were found to be useful. Ion induced perturbations of any solvent system will be dictated by the structure of the particular solvent system. A knowledge of the structure of the aquo-alcoholic mixtures is imperative to develop an idea regarding ion induced perturbations as mirror image relations because of compensation of ΔH° and TΔS° (and of ΔH°t and TΔS°t) will be observed in any solvent system. The thermodynamic measurements provide a summary of all interaction energies over a long time. To comprehend the rational structural details of the solvent systems, accurate thermodynamic measurements alongwith relaxation experiments providing high time and good structural resolutions are necessary.

Determination of the Gibbs energies of transfer for some monovalent ions from water to triethylphosphite

The Gibbs energies of transfer, ΔtG0 for 9 monovalent ions from water to triethylphosphite are reported. The Gibbs energies of transfer have been determined from solubility product measurements of 1:1 salts. The extrathermodynamic tetraphenylarsonium tetraphenylborate (TATB) assumption has been applied in order to calculate the contribution from the individual ions. It is shown that soft electron-pair acceptors such as the silver(I) ion are strongly solvated in triethylphosphite, while hard electron acceptors with low charge density such as the alkali metal ions are almost equally solvated in triethylphosphite and water. The inorganic anions are so weakly solvated in triethylphosphite that solubility product measurements were not possible to perform with sufficient accuracy on salts with inorganic anions due to low solubilities. The only anions studied are tetraphenylborate and picrate.

Thermodynamic Properties of Transfer for Tetraphenylarsonium Tetraphylborate from Water to n‐Alkanols

AbstractSolubilities of tetraphenylarsonium tetraphenylborate (Ph4AsB‐Ph4) in water, methanol, ethanol, 1‐propanol, 1‐butanol, 1‐pentanol, 1‐hexanol and 1‐octanol at T = 293.2, 298.2, 303.2 and 308.2 K have been determined by spectrophotometry. The standard transfer Gibbs energy (Δtr‐G0w‐s) and entropy (Δtr‐G0w‐s) of Ph4AsBPh4 from water to the n‐alkanols at temerature from 293.2 K to 308.2 K have been obtained. Furthermore, the contribution of microscopic interaction to the standard Gibbs energy of transfer for Ph4AsBPh4 was calculated and discussed. The results show that the effect of hydrophobic interaction of Ph4AsBPh4 on its transfer process is the most important factor. According to the thermodynamical principle, the transfer process of Ph4AsBPh4 from water to the n‐alkanols is the entropy dominated.

Determination of the transfer thermodynamic functions for some monovalent ions from water to N,N′-dimethylpropyleneurea

The transfer thermodynamic functions for 19 monovalent ions from water to N,N′-dimethylpropyleneurea (1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidione) are reported. The Gibbs energies of transfer, ΔtGo, have been determined from solubility product or potentiometric measurements, and the heats of transfer, ΔtHo, have been determined calorimetrically. The entropies of transfer, ΔtSo, have been calculated from these ΔtGo and ΔtHo values. The extrathermodynamic tetraphenylarsonium tetraphenylborate (TATB) assumption has been applied in order to calculate the contribution from the individual ions. The hard alkali metal ions are strongly solvated by N,N′-dimethylpropyleneurea as is the soft silver(I) ion. The inorganic anions are all more strongly solvated in water than in N,N′-dimethylpropyleneurea, and the ΔtSo values are markedly negative. In spite of the stronger solvation of the anions in water, the heats of transfer for some of these are exothermic. The exothermic heats of transfer arise from the difference in bulk order between water, which is well-ordered through hydrogen bonding, and N,N′-dimethylpropyleneurea, which has a significantly lower bulk order than water. The solvation of monovalent ions shows a similar pattern in N,N′-dimethylpropyleneurea to that previously found in dimethylsulfoxide.

Hydrophobic Ions in TIP5P Water and at a Water−Chloroform Interface: The Effect of Sign Inversion Investigated by MD and FEP Simulations

According to the TATB (tetraphenylarsonium tetraphenylborate) assumption, large isosterical ions of opposite charge have identical free energies of solvation in any solvent. In this context, we present a molecular dynamics study of the solvation of tetrahedral (AsPh4+ vs BPh4-) and large spherical (S+ vs S-) ions in water using the recently developed TIP5P model. The results markedly differ from those obtained in TIP3P water and are in better agreement with the TATB hypothesis. According to free energy perturbation calculations, S- is better hydrated than S+, but the difference, ΔG+-, in hydration energies is much weaker in TIP5P (3.2 kcal/mol) than in TIP3P water (27.3 kcal/mol) which leads to an artifactually positive electrostatic potential at the center of the neutral S0 species. BPh4- is better hydrated than AsPh4+ and, contrary to the TATB assumption, ΔG+- markedly depends on the details of charge distributions. The set8 charges equally diluted on all atoms lead to ΔG+- of 4.3 kcal/mol only, much le...

Are the Hydrophobic AsPh4+ and BPh4- Ions Equally Solvated? A Theoretical Investigation in Aqueous and Nonaqueous Solutions Using Different Charge Distributions

We present a molecular dynamics study of the solvation properties of the tetrahedral AsPh4+ and BPh4- ions in water and chloroform solutions. According to the “extrathermodynamic” TATB (tetraphenylarsonium tetraphenylborate) hypothesis, these nearly isosterical ions have identical free energies of solvation in any solvent, as the latter are generally assumed to display little dependence on the details of the charge repartition, provided that the total ± charge is delocalized and that the ion's periphery is relatively inert. We compare eight different sets of charges obtained consistently for both ions and find that the anion is always better hydrated than the cation, as evidenced by ion−solvent interaction energies and changes in free energies of ion charging. This is explained by specific OH−π bridging interactions in the anion and the positive electrostatic potential at the center of the fictitious AsPh40 and BPh40 all-neutral species. With all models, the cation is also predicted to be more easily transferred from water to dry chloroform. The conclusions obtained with standard solvent models (TIP3P water and OPLS chloroform) are validated by tests with the polarizable Wallqvist and Berne water model and the Chang et al. chloroform model, and with computer simulations on a “wet chloroform” solution. The recently developed TIP5P water model yields, however, much closer hydration energies of AsPh4+ and BPh4-. The importance of “long-range” electrostatic interactions on the charge discrimination by solvent is demonstrated by the comparison of standard vs corrected methods to calculate the Coulombic interactions. These results are important in the context of the “TATB hypothesis” and for our understanding of solvation of large hydrophobic ions in pure liquids or in heterogeneous liquid environments.

Application of the tetraphenylarsonium tetraphenylborate (TATB) assumption to the hydration entropies of ions

The hydration entropy of ions is calculated from their entropy in the ideal gaseous state and the standard entropy of their aqueous solutions. The application of the tetraphenylarsonium tetraphenylborate (TATB) and the cognate tetraphenylphosphonium tetraphenylborate (TPTB) assumptions in obtaining the latter is explored, using newly determined heat capacity data for crystalline tetraphenyl phosphonium and arsonium perchlorates, their redetermined solubility data, both over a temperature interval, and data from the literature. The results are compared with those based on the widely accepted estimate of the standard entropy of the aqueous hydrogen ion based on thermocell data.

Ion-Solvation Behavior of Some Copper(II) Salts in Isodielectric Solvent Mixtures of Methanol and N-Methyl-2-pyrrolidinone at 30 °C

The selective solvation behavior of copper(II) iodate, formate, and benzoate in the isodielectric solvent mixtures of methanol and N-methyl-2-pyrrolidinone has been studied using the standard Gibbs transfer energies and solvent transport number measurements. The standard Gibbs transfer energies of various ions were determined on the basis of the tetraphenylarsonium tetraphenylborate (TATB) assumption. The results were interpreted in terms of heteroselective solvation of all the salts with copper(II) ion being selectively solvated by N-methyl-2-pyrrolidinone and anions by methanol.

Solubility and Thermodynamic Transfer Functions of Cesium Dianilinetetraisothiocyanatochromate(III)

The solubilities of cesium dianilinetetraisothiocyanatochromate(III) in water as well as in aqueous methanol, isopropyl alcohol, tert-butyl alcohol and acetonitrile were measured as a function of temperature and solvent composition. The Gibbs energies, enthalpies and entropies of transfer of the salt from water to the given solvents have been evaluated from experimental data. The contribution of [Cr(C6H5NH2)2(NCS)4]- ion to the Gibbs energy of transfer of the investigated salt has been calculated using the tetraphenylarsonium tetraphenylborate (TATB) reference electrolyte assumption.

Preferential solvation of some silver(I) salts in iso‐dielectric mixtures of methanol and N‐Methyl‐2‐pyrrolidinone at 30°

AbstractThe solvation behavior of various silver(I) salts, viz. silver (I) iodate, bromate and sulfate in iso‐dielectric solvent mixtures of methanol and N‐methyl‐2‐pyrrolidinone (NMP) has been investigated using Gibbs transfer energies and solvent transport number measurements. The Gibbs transfer energies of the salts were split into their individual ionic contributions using both negligible liquid junction potential method (nLJP) and the reference electrolyte method using tetraphenylarsonium tetraphenylborate (TATB). The results show a significant hetero‐selective solvation of all salts beyond XNMP = 0.5 with silver ion being selectively solvated by NMP and the anions by methanol.

A critical review of methods for obtaining ionic volumes in solution

The various major methods for obtaining individual or "absolute" ionic standard partial molar volumes V°(on) from whole electrolyte data in both aqueous and nonaqueous solutions are critically reviewed. A number of undetected errors in previous analyses are pointed out, and it is demonstrated that the reported agreement amongst the various methods in aqueous solution is largely fortuitous. All methods are shown to be unsatisfactory to varying degrees, with the reference electrolyte approach, using an electrolyte such as tetraphenylarsonium tetraphenylborate, appearing to be the least objectionable of those currently available. It is recommended that, subject to future theoretical and experimental developments, the assumption that, at 25°C: V°(Ph4As+) - V°(BPh4) = 8 cm3-mol-1, or its equivalent: V°(Ph4P+) - V°(BPh-4) = 2 cm3-mol-1 be used in all solvents.

Gibbs Transfer Energies of Some Uni-Univalent Salts in Water—N-Methyl-2-Pyrrolidinone Solvent Mixtures at 30°C

Abstract The standard Gibbs transfer energies of some uni-univalent electrolytes like potassium picrate, tetraphenylarsonium picrate, potassium and silver tetraphenyl borate were determined in water + N-Methyl-2-Pyrrolidinone mixtures from solubility measurements at 30 °C. They were split into respective ionic values on the basis of the reference electrolyte method using tetraphenylarsonium tetraphenylborate. The variation of transfer energies of the ions with composition of solvent are examined and discussed in terms of the possible ion-solvent interactions.

Preferential solvation of silver(I)-cryptand-2,2,2 perchlorate complex in water + acetonitrile and methanol + acetonitrile mixtures

The preferential solvation of silver(I)-cryptand-2,2,2 perchlorate complex in methanol (MeOH) + acetonitrile (AN) and water + AN mixtures (25°C) was studied by determination of Gibbs transfer energies and solvent transport numbers over the complete range of solvent compositions. The Gibbs transfer energies of the complex salt were split into ionic components by applying the negligible liquid junction potential (nLJP) assumption and reference electrolyte methods using tetraphenylarsonium tetraphenylborate (TATB) in MeOH + AN and water + AN mixtures respectively. The transfer energy of the complexed cation is negative and decreases continuously with the addition of AN (up to X AN = 0.9 in MeOH + AN mixtures and up to X AN = 0.5 in water + AN mixtures), while that of perchlorate ion increases under the same conditions in both mixed solvents. The solvent transport number Δ AN of AN is positive and passes through a maximum of 5.0 at X AN = 0.55 in MeOH + AN mixtures and 8.7 at X AN = 0.45 in water + AN mixtures. The results suggest a heteroselective solvation of the salt, with the complex cation being selectively solvated by AN and the perchlorate ion by MeOH or water in the two mixed solvents.

Determination of the transfer thermodynamic functions for the zinc(II), cadmium(II), mercury(II) and mercury(I) ions from water to methanol, dimethyl sulfoxide, acetonitrile, pyridine and N,N-dimethylthioformamide and of standard electrode potentials of the M2+/M(s) couples in these solvents

The transfer thermodynamic functions for the zinc, cadmium, mercury(II) and mercury(I) ions from water to methanol, dimethyl sulfoxide, acetonitrile, pyridine and N,N-dimethylthioformamide are reported. The ΔtG⊖ values are calculated from potentiometrically determined standard electrode potentials in the different solvents with a silver reference electrode, and the ΔtH⊖ values are obtained from calorimetrically determined enthalpies of solution of the anhydrous metal trifluoromethylsulfonates. The entropies of transfer, ΔtS⊖, are calculated from the experimentally obtained ΔtG⊖ and ΔtH⊖ values; all of the measurements were performed at 25 °C. The extrathermodynamic tetraphenylarsonium tetraphenylborate (TATB) assumption has been applied in order to calculate the contributions from the single ions. The studied ions are more strongly solvated in N,N-dimethylthioformamide, pyridine and dimethyl sulfoxide than in water, while they are more weakly solvated in methanol and acetonitrile. The entropies of transfer are negative for all the systems under study except for the cadmium ion to N,N-dimethylthioformamide.

Thermodynamic study on the transfer of the tin(II), lead(II) and alkaline-earth-metal ions from water to methanol, dimethyl sulfoxide, acetonitrile, pyridine and N,N-dimethylthioformamide

The thermodynamic functions for the transfer reactions of the tin(II), lead(II) and alkaline-earth-metal ions from water to methanol, acetonitrile, dimethyl sulfoxide and pyridine, and of the tin(II) and lead(II) ions to N,N-dimethylthioformamide, are reported. The Gibbs energies of transfer, ΔtG⊖, have been calculated from the standard electrode potentials of the Sn2+/Sn(s) and Pb2+/Pb(s) couples, which have been determined potentiometrically with the Ag(s)/Ag+ electrode as reference in the title solvents, and the Gibbs energies of transfer of the silver ion. The Gibbs energies of transfer of the alkaline-earth-metal ions were calculated from electrode or halfwave potentials of the M2+/M(am) couples in the title solvents and the difference in standard electrode potential between the M2+/M(am) and M2+/M(s) couples reported in the literature. The enthalpies of transfer, ΔtH⊖, have been obtained from calorimetrically determined enthalpies of solution of the anhydrous metal trifluoromethylsulfonates. The entropies of transfer, ΔtS⊖, have been calculated from the experimentally determined ΔtG⊖ and ΔtH⊖ values. All measurements have been carried out at 25 °C. The extrathermodynamic tetraphenylarsonium tetraphenylborate (TATB) assumption has been applied in order to calculate the contributions from the single ions. The tin(II) and lead(II) ions are solvated more strongly in dimethyl sulfoxide and N,N-dimethylthioformamide than in water, while they are solvated more weakly in methanol and acetonitrile. The small tin(II) ion is solvated more weakly and the larger lead(II) ion is solvated more strongly in pyridine than in water. The alkaline-earth-metal ions are solvated more strongly in dimethyl sulfoxide than in water, while methanol and the nitrogen donor solvents acetonitrile and pyridine solvate these ions more weakly than water. The enthalpies of transfer for these ions to the solvents studied are exothermic except for the tin(II), calcium and strontium ions to acetonitrile. The entropies of transfer to all solvents are markedly negative except for N,N-dimethylthioformamide where the TΔtS⊖ values are close to zero. The difference in solvation of an ion between two solvents is mainly dependent on the bonding character of the ion–solvate bonds and on the way in which the ion affects the solvent bulk.

Determination of the transfer thermodynamic functions for some monovalent ions from water to N,N-dimethylthioformamide, and for some anions from water to methanol, dimethyl sulfoxide, acetonitrile and pyridine, and standard electrode potentials of some M+/M(s) couples in N,N-dimethylthioformamide

The transfer thermodynamic functions for 22 monovalent and two divalent ions from water to N,N-dimethylthioformamide, and for the nitrate, hydrogen sulfate, sulfate, permanganate and dichromate anions from water to methanol, acetonitrile, dimethyl sulfoxide and pyridine, have been reported. The Gibbs energies of transfer, ΔtG⊖, have been determined from solubility product or potentiometric measurements, and the enthalpies of transfer, ΔtH⊖, have been determined calorimetrically. The entropies of transfer, ΔtS⊖, have been calculated from the experimentally obtained ΔtG⊖ and ΔtH⊖ values. The extrathermodynamic tetraphenylarsonium tetraphenylborate (TATB) assumption has been applied in order to calculate the contribution from the individual ions. Previously determined transfer thermodynamic functions for monovalent ions from water to methanol, acetonitrile, dimethyl sulfoxide, pyridine, tetrahydrothiophene and liquid ammonia are summarized and discussed in this paper. The transfer thermodynamic behaviour of the monovalent ions shows that the cations studied can be divided into two groups, metal ions and cations with hydrocarbon groups facing the solvent, and the anions can accordingly be divided into the subgroups inorganic anions and anions with hydrocarbon group(s) facing the solvent. The ΔtG⊖ and ΔtH⊖ terms counterbalance each other in such a way that the ΔtS⊖ terms become almost constant for each of these subgroups of ions in a certain solvent. The hard alkali-metal ions are as strongly solvated by dimethyl sulfoxide as by any other solvent, while the weakest solvation is found in N,N-dimethylthioformamide among the solvents in this study. The soft silver ion is, on the other hand, most strongly solvated in N,N-dimethylthioformamide. The strongest solvation of the thallium(I) ion, which is a borderline acceptor, is found in dimethyl sulfoxide and N,N-dimethylthioformamide. The transfer thermodynamics of the ammonium and tetraalkylammonium ions display an irregular pattern with the NH4+ ion behaving as the hard monovalent metal ions and the (C4H9)4N+ ion behaves as the tetraphenylarsonium ion. The inorganic anions are all more strongly solvated in water than in any other solvent, and the ΔtS⊖ values are pronouncedly negative, while the anions with hydrocarbon groups are more strongly solvated in the non-aqueous solvents and with positive ΔtS⊖ values.

Solvent effects on the solubilities of reference electrolytes

Solubilities of bis(biphenyl)chromium(I) tetraphenylborate were measured in 25, solubilities of tetraphenylarsonium tetraphenylborate in nine and solubilities of bis(biphenyl)chromium(0) in seven nonaqueous solvents. Linear dependences of the pKs-values for these compounds as well as the pKs values for tetraphenylstibonium tetraphenylborate, tetraphenylmethane and tetraphenylgermane were observed. The relations between the pKs-values of the above mentioned compounds and solvent parameters as well as solvent structure are discussed.

Single-ion enthalpies and entropies of transfer from water to aqueous urea solutions at 298.15 K

In this paper we report enthalpies of solution at infinite dilution [Formula: see text] at 298.15 K for tetraphenylarsonium chloride (Ph4AsCl), sodium tetraphenylborate (NaBPh4), sodium chloride (NaCl), sodium bromide (NaBr), and sodium iodide (NaI) in water and aqueous solutions containing 5, 10, 20, and 30% urea by weight. Enthalpies of transfer from water to aqueous urea solutions are reported. Single-ion enthalpies of transfer [Formula: see text] have been calculated using the tetraphenylarsonium tetraphenylborate, (TATB) reference electrolyte assumption. These single-ion enthalpy data have been combined with single-ion Gibbs functions of transfer [Formula: see text] reported in the literature to obtain single-ion entropies of transfer [Formula: see text] for the urea + water mixed solvent system. The results of this single-ion analysis are discussed in terms of the impact of electrolytes on the structure of aqueous urea solutions.

Ion solvation in lithium battery electrolyte solutions. 1. Apparent molar volumes

Apparent molar volumes, Vφ{symbol}(MX), of seven electrolytes (NaClO4, NaCF3SO3, NaBPh4, LiClO4, LiAsF6, Ph4AsCF3SO3 and KCF3SO3) have been determined by vibrating-tube densimetry in nonaqueous solvent mixtures of propylene carbonate (PC) with acetonitrile (AN), dimethoxyethane (DME) and tetrahydrofuran (THF). Vφ{symbol}(MX) was measured at an electrolyte concentration of 0.05M over the entire solvent composition range wherever possible. Ionic apparent molar volumes of transfer, ΔtV φ(ion), were obtained via the tetraphenylarsonium tetraphenylborate (TATB) assumption. ΔtV φ(ion) from PC to the mixed solvents are generally strongly negative for both cations and anions consistent with the greater compressibilities and lower dielectric constants of the cosolvents. In PC/AN mixtures cations and anions have similar values of ΔtV φ(ion) but in PC/DME and PC/THF mixtures they differ considerably. Cationic volumes show the expected dependence on ion-size but the differences among the anion volumes are much greater than expected at high cosolvent compositions. These effects are discussed in terms of preferential solvation and other solvent interactions. The implications of these findings for lithium batteries are briefly discussed.