Ions In Non-aqueous Solvents Research Articles

Complex Formation of Copper(II) Ions with Phthalate Ions in Non-Aqueous Solvents

Complex Formation of Copper(II) Ions with Phthalate Ions in Non-Aqueous Solvents

Specialties of the structure and conductivity of the non-aqueous electrolytes based on alkali metal bis (salicyl) borates and bis (oxalate) borates

The structure and coordination environment of non-aqueous electrolytes based on bis(salicyl)borates of lithium, sodium, potassium, tetramethylammonium (MeBSB) and bis(oxalato)borates from lithium to cesium (MeBOB) using NMR spectroscopy have been investigated. Bis(salicyl)borates (BSB) and bis(oxalate)borates (BOB) of alkali metals and organic cations are considered as promising electroconductive components of electrolytes of modern chemical sources of current (lithium, sodium ion batteries and super-capacitors). The salts were synthesized by the microwave radiation method. The 13C and 11B NMR spectra analysis determined the presence of symmetric structure in BOB anion and the presence of two optical conformations of the BSB anion with labile coordination environment of boron. The conformations of the BSB are the result of the ion contact pairs formation. In the case of tetramethylammonium cation the presence of conformations are depended on the reactive medium. The conformational lability of the coordination sphere of NaBSB dissolved in DMAA is connected with increasing of the integral intensity of carboxyl group singles relatively signals of carbon atoms in fragments of another functional affiliation when the time delay between radio frequencies varies within 2-15 seconds. The difference in the structure of these anions leads to a change in the thermal dependence of the electrical conductivity of BSB and the transport of ions in non-aqueous solvents. Maximum electrical conductivity of salt solutions in DMFA is achieved at close concentrations of 0.75 m for KBSB and 0.77-1 m for NaBSB. The solubility of BSB is better than the BOB. Based on the measurements of the conductivity and the data of electrochemical impedance spectroscopy (the angle of inclination of spectra in the Nyquist coordinates in the low frequency range, the phase angle shift at a frequency) it was proposed the existence of two ways of ions and charge transfer in the electrolytes: diffusion and relay transport. The possibility of formation of a labile salt complex with a solvent due to hydrogen bonds is established.

Specialties of the structure and conductivity of the non-aqueous electrolytes based on alkali metal bis (salicyl) borates and bis (oxalate) borates

The structure and coordination environment of non-aqueous electrolytes based on bis(salicyl)borates of lithium, sodium, potassium, tetramethylammonium (MeBSB) and bis(oxalato)borates from lithium to cesium (MeBOB) using NMR spectroscopy have been investigated. Bis(salicyl)borates (BSB) and bis(oxalate)borates (BOB) of alkali metals and organic cations are considered as promising electroconductive components of electrolytes of modern chemical sources of current (lithium, sodium ion batteries and super-capacitors). The salts were synthesized by the microwave radiation method. The 13C and 11B NMR spectra analysis determined the presence of symmetric structure in BOB anion and the presence of two optical conformations of the BSB anion with labile coordination environment of boron. The conformations of the BSB are the result of the ion contact pairs formation. In the case of tetramethylammonium cation the presence of conformations are depended on the reactive medium.
 The conformational lability of the coordination sphere of NaBSB dissolved in DMAA is connected with increasing of the integral intensity of carboxyl group singles relatively signals of carbon atoms in fragments of another functional affiliation when the time delay between radio frequencies varies within 2-15 seconds. The difference in the structure of these anions leads to a change in the thermal dependence of the electrical conductivity of BSB and the transport of ions in non-aqueous solvents. Maximum electrical conductivity of salt solutions in DMFA is achieved at close concentrations of 0.75 m for KBSB and 0.77-1 m for NaBSB. The solubility of BSB is better than the BOB. Based on the measurements of the conductivity and the data of electrochemical impedance spectroscopy (the angle of inclination of spectra in the Nyquist coordinates in the low frequency range, the phase angle shift at a frequency) it was proposed the existence of two ways of ions and charge transfer in the electrolytes: diffusion and relay transport. The possibility of formation of a labile salt complex with a solvent due to hydrogen bonds is established.

Multinuclear magnetic resonance study of N-phenyl-aza-15-crown-5 complexes with lithium, sodium and caesium ions in nonaqueous solvents

Nuclear magnetic resonances of 7Li, 23Na and 133Cs nuclei were used to study the lithium, sodium and caesium ion complexes with N-phenyl-aza-15-crown-5 (PhA15C5) in nitromethane (NM), acetonitrile (AN) and AN–NM mixture solutions. The chemical shift data indicated that these cations form 1 : 1 cation : ligand complexes with PhA15C5. The formation constants of the resulting complexes were calculated from the computer fitting of the chemical shift–mole ratio data. The results show that the complex formation constants of PhA15C5 with these cations vary in the order of Na+ > Li+ ≫ Cs+. Complexation of the lithium ion was also studied in binary AN–NM mixtures. It was found that the stability of the resulting complexes increases by an increase in the amount of NM in the solvent mixture.

Complexation of Metal Ions in Nonaqueous Solvents

Complexation of Metal Ions in Nonaqueous Solvents

Simulation of Charged Ion Migration in Capillary Zone Electrophoresis System Using Particle in Cell Method

Traditional numerical schemes use the concentration diffusion equation to simulate the solute concentration distribution in capillary zone electrophoresis (CZE) systems. However, although this equation adequately describes the diffusion of a solute liquid in such systems, it cannot describe the different motions of the differently charged solute ions. Therefore, this study employs a particle model to simulate solute ionic migration. Using the Navier–Stokes equation and the (particle in cell) PIC method, this study examines the absolute mobility of negatively and positively charged ions in non-aqueous solvents in a CZE system. The results show that the zeta potential on the channel wall affects the migration of the positive and negative ions in the electrical double layer (EDL) in different ways. Specifically, the positive ions accumulate at the channel wall, while the negative ions are pushed out of the EDL. Furthermore, it is shown that the positive ions migrate more rapidly than the negative ions in the injection process.

Recent advances in tailoring the aggregation of heavier alkaline earth metal halides, alkoxides and aryloxides from non-aqueous solvents

This overview on one of the subjects treated in our group deals with the synthesis and study of low-dimensional polymer and molecular solid state structures formed with alkaline earth metal ions in non-aqueous solvents. We have chosen several synthetic approaches in order to obtain such compounds. The first concept deals with the "cutting out" of structural fragments from a solid state structure of a binary compound, which will be explained with reference to BaI2. Depending on the size and concentration of oxygen donor ligands, used as chemical scissors on BaI2, three-, two-, one- and zero-dimensional derived adducts of BaI2 are obtained, comparable to a structural genealogy tree for BaI2. A second part deals with the supramolecular approach for the synthesis of low dimensional polymeric compounds based on alkaline earth metal iodides, obtained by the combination of metal ion coordination with hydrogen bonding between the cationic complexes and their anions. Certain circumstances allow rules to be established for the prediction of the dimensionality of a given compound, contributing to the fundamental problem of structure prediction in crystal engineering. A third section describes a synthetic approach for generating pure alkaline earth metal cage compounds as well as alkali and alkaline earth mixed metal clusters. A first step deals with different molecular solvated alkaline earth metal iodides which are investigated as a function of the ligand size in non-aqueous solvents. These are then reacted with some alkali metal compound in order to partially or totally eliminate alkali iodide and to form the targeted clusters. These unique structures of ligand stabilized metal halide, hydroxide and/or alkoxide and aryloxide aggregates are of interest as potential precursors for oxide materials and as catalysts. Approaches to two synthetic methods of the latter, sol-gel and (MO)CVD (metal-organic chemical vapour deposition), are investigated with some of our compounds. (D. C. Bradley, Chem. Rev., 1989, 89, 1317-22; K. G. Caulton and L. G. Hubert-Pfalzgraf, Chem. Rev., 1990, 90, 969-95; T. P. Hanusa, Coord. Chem. Rev., 2000, 210, 329-367; T. P. Hanusa, in Comprehensive Coordination Chemistry II, ed. J. A. McCleverty and T. J. Meyer, Elsevier, Amsterdam, 2004, vol. 3, 1-92). Finally, the physical properties of some of our compounds are described qualitatively in order to show the wide spectrum of possibilities and potential applications for chemistry in this field.

Standard Partial Molar Volumes of Electrolytes and Ions in Nonaqueous Solvents

AbstractFor Abstract see ChemInform Abstract in Full Text.

Standard partial molar volumes of electrolytes and ions in nonaqueous solvents.

To date, much has been achieved in the determination of the molar volumes of electrolytes and ions in nonaqueous solvents. This review compiles and critically assesses the data available in the open literature for the standard partial molar volumes of electrolytes, V°, and their ionic constituents, V°(ion), in nonaqueous solvents at 298.15 K. Focus is on electrolytes composed of simple (monatomic and asymmetrical polatomic) ions, and salts containing ions such as triflate and acetate.

Synthesis and crystal structure of two dimeric cadmium(II) complexes bonded with pseudohalides, 1.1 and 1.3 bonding

Abstract Two different complexes were obtained from (dmpp) and Cd(II) ions with the aid of pseudohalide ions in non-aqueous solvents. The dinuclear complex formed with thiocyanate ions show, using XRD, to posses two 1.3 bond μ bridges [CdL(SCN)2]2. The other dinuclear complex was also seen to form with cyanate ions but with the μ-bridge in a 1.1 position [CdL(OCN)2]. All Cd atoms are located in a distorted octahedral environment in 1 and 2 complexes. The Cd…Cda distances are 6.032(4) Å in 1 and 3.704(3) Å in 2, respectively. The N—C—S and O—C—N angles are approximately linear as 178.1(3) and 178.6(3)° in 1 and 177.2(5) and 176.9(7)° in 2, respectively. The Cd—(μ N,S-NCS)2—Cda bonds form a zig-zag structure in 1 and the Cd—(μ O,N-OCN)2—Cda bonds form a distorted square planar in 2.

Spectroscopic properties of uranyl chloride complexes in non-aqueous solvents

The complex formation of uranyl with chloride ions in non-aqueous solvents (acetone, tributylphosphate and methyl-i-butylketone) was studied by absorption, luminescence and MCD spectroscopy. The maximal coordination of the uranyl ion by chloride ions in these organic solvents was found to be four, which is in agreement with single crystal data. The MCD spectra unambiguously exclude the existence of [UO2Cl3]− with D3h coordination symmetry. For the intermediately formed complexes we propose a structure of the type: UO2Cl2(solv)4, with an orthorhombic symmetry. For these intermediate complexes, the 19 500–22 000 cm−1 region of the absorption spectrum exhibits an intensity enhancement with respect to that of the solvated uranyl ion. This intensity enhancement as well as the increase in total luminescence intensity is explained in terms of vibronic coupling of the first electronic state (Πg) with the asymmetric stretching (νa:a2u) and the bending (νb:eu) vibrations of the uranyl ion and the out-of-plane bending mode of the equatorial ligands (ν10:b1u). The spectra are dominated by transitions arising from the σu+δu configuration. The spectroscopic properties of the UO2Cl2(TBP)x complexes are compared with those of the UO2(NO3)2(TBP)2 complex (TBP = tributylphosphate).

Comments on the mechanism of the electrochemical reduction of sulphur in dimethylformamide

This paper presents a clarification of the electrochemical behaviour of sulphur and polysulphide ions in non-aqueous solvents following the recent publication of a paper [Electrochem. Commun. 3 (2001) 514] devoted to the mechanism of the electrochemical reduction of sulphur in dimethylformamide.

Electrophoretic mobilities of large organic ions in nonaqueous solvents: determination by capillary electrophoresis in propylene carbonate, N,N-dimethylformamide, N,N,-dimethylacetamide, acetonitrile and methanol.

The mobilities of the monocharged permanent tertraphenylphosphonium cation and tetraphenylborate anion are determined by capillary zone electrophoresis in different organic solvents as a function of the ionic strength, I, of the background electrolyte. The nonaqueous solvents are propylene carbonate (PC), N,N-dimethylformamide (DMF), N,N,-dimethylacetamide (DMA), acetonitrile (MeCN) and methanol (MeOH). The ionic strength is between 5 and 50 mmol/L. The mobility as a function of I is in good agreement with the theory of Debye, Hückel and Onsager (DHO), extended by the ion size parameter as introduced by Falkenhagen and Pitts. The values of the limiting DHO slopes of the mobility vs. I curves (the slopes express the influence of the solvent on the reduction of the mobility with increase of I) decrease in the order MeCN > MeOH > DMF > DMA > PC. Absolute mobilities (obtained by extrapolation to I = 0) of a particular ion differ by a factor of about 7 between the solvents. However, constancy within 10% is observed for their Walden products (the absolute mobility multiplied with the solvent's macroviscosity). The role of dielectric friction on the mobility of the present monocharged, large analyte ions is discussed according to the theory of Hubbard and Onsager. Based on the radii of the ions, the static permittivity of the solvent and its permittivity at infinite frequency, and the relaxation time of polarization, an equal contribution of dielectric and hydrodynamic friction is predicted in MeOH as solvent. Experimental data are in contrast to this prediction, indicating the overestimation of dielectric friction, and the dominance of hydrodynamic friction on the migration of the analyte ions in all solvents under consideration.

Solvation Structure of Solvated Cu(I) Ions in Non-Aqueous Solvents as Studied by EXAFS and ab initio Molecular Orbital Methods

The structure parameters around the Cu(I) ion in pyridine (PY), 4-methylpyridine (4MPY), 2-methylpyridine (2MPY), 2,6-dimethylpyridine (26DMPY), and acetonitrile (AN) were determined by the extended X-ray absorption fine structure (EXAFS) method. The solvation structures of the Cu(I) ion in PY, 4MPY, and AN are 4-coordinate tetrahedral with Cu-N bond lengths of 205, 205, and 200 pm, respectively. In the case of 2MPY and 26DMPY, the Cu(I) ion has a 3-coordinate triangular structure with a Cu-N bond length of 201 pm. Such a decrease in the coordination number was interpreted in terms of the bulkiness of the solvent molecules. In order to clarify the most stable solvation structure of the Cu(I) ion, we carried out ab initio molecular orbital calculations for the solvation system of [Cu(NCH)n]+ (n = 1 - 6 ) where the steric effect is negligible. The Gibbs free energy of solvation was the smallest in the case of n = 4 and the 4-coordinate tetrahedral solvation of the Cu(I) ion was theoretically evaluated as most stable. The enthalpy of solvation monotonously decreases with increasing n, while the entropy of solvation proportionally increases. Although a larger gain of enthalpy is observed for the octahedral structure rather than the tetrahedral one, the entropic loss for the former overcomes the enthalpic gain.

Molar Volumes and Heat Capacities of Electrolytes and Ions in Nonaqueous Solvents: 1. Formamide

Apparent molar volumes and heat capacities of 27 electrolytes have been measured as a function of concentration in formamide at 25°C using a series-connected flow densimeter and Picker calorimeter system. These data were extrapolated to infinite dilution using the appropriate Debye–Huckel limiting slopes to give the corresponding standard partial molar quantities. Ionic volumes and heat capacities at infinite dilution were obtained by an appropriate assumption based on the reference electrolyte Ph4PBPh4 (TPTB). The ionic volumes, but not the heat capacities, agree reasonably well with previously published statistically based predictions. The values obtained are discussed in terms of simple models of electrolyte solution behavior and a number of interesting features are noted, including, possible dependencies of ionic volumes on solvent isothermal compressibility and of ionic heat capacities on solvent electron acceptor abilities.

Conductance study of the complexation of substituted and lariat 16-crown-5 derivatives with alkali metal ions in nonaqueous solvents

Formation constants (K ML) of 1:1 complexes of 15-(2,5-dioxahexyl)-15-methyl-16-crown-5 (L16C5) and 15,15-dimethyl-16-crown-5 (DM16C5) with alkali metal ions were determined in acetonitrile (AN) and propylene carbonate (PC) by conductometry at 25°C. Except for the case of Li+-and K+-16C5 complexes in PC, the selectivity sequences of L16C5 and DM16C5 are identical with those of the parent crown ether 16-crown-5 (16C5) regardless of the solvent (AN, PC, methanol) (Na1 > Li+ > K+ > Rb+ > Cs+), which show the size-fit correlation. The selectivities of L16C5 and DM16C5 for the alkali metal ions are governed not by the sidearms but by the cavity size. The stability of the crown ether complex is dependent not on the dielectric constant but largely on the donor number of the solvent. TheK ML(M1 +)/K ML(M2 +) ratio of L16C5 or 16C5 varies very much with the solvent in the cases of M1=Na, M2=K and M1=Na, M2=Li, but that of DM16C5 is almost constant regardless of the solvent.

NMR Study of Benzo-15-Crown-5 Complexes with 7Li+ and 133Cs+ Ions in Nonaqueous solvents

Complexes of benzo-15-crown-5 macrocycle with Li+ and Cs+ ions were investigated by 7Li and 133Cs NMr in a number of nonoqueous solutions. The resulting 1:1 complex with Li+ ion was found to be much more stable than that with Cs+ ion. With the exception of pyridine solutions the stabilities of the complexes varied inversely with the Gutmann donor number of the solvents. Some indirect evidence for the formation of very weak 2:1 complexes was observed.

A Conductance Study of 1:1 Complexes of 15-Crown-5, 16-Crown-5, and Benzo-15-crown-5 with Alkali Metal Ions in Nonaqueous Solvents

Abstract Conductivities of alkali metal salts in the presence of 15-crown-5 (15C5), 16-crown-5 (16C5), and benzo-15-crown-5 (B15C5) were measured at 25 °C in acetonitrile, propylene carbonate, and methanol. Formation constants (KML+) of 1:1 complexes of 15C5 and 16C5 with alkali metal ions and conductance parameters (λ0 and å) of the Na+ complexes of 15C5, 16C5, and B15C5 were determined, λ0 and å being limiting ionic molar conductivity and distance of closest approach of ions, respectively. In general, selectivities of 15C5 and 16C5 for alkali metal ions show the size-fit correlation. In contrast to 15C5, 16C5 forms much the most stable complex with Na+ in every solvent. Generally, KML+-value sequences of a given crown ether complex for the solvents are the reverse of donor-number sequences of the solvents. Value of å increases with an increase in the cationic size (Na+→Na(15C5)+→Na(16C5)+→Na(B15C5)+). Mobility of the Na+–crown ether complex decreases with an increase in the size of the crown ether. From λ0 values and Walden products of these Na(crown ether)+ complexes and a tetrapropylammonium ion, it seems likely that Na(15C5)+ and Na(16C5)+ act as structure breakers in hydrogen-bonding solvents, whereas Na(B15C5)+ as a structure maker.

Linear correlation between entropies of complexation of cryptand 222 with metal ions in non-aqueous solvents and entropies of solvation of these ions in these solvents

A linear correlation between entropies of complexation of cryptand 222 with alkali-metal and silver cations in non-aqueous solvents and entropies of solvation of these ions in these solvents is shown. This correlation can be used for the evaluation of entropies for the transfer of alkali-metal and silver cations from water to non-aqueous solvents from data for entropies of complexation of alkali-metal and silver cryptates in the appropriate solvents or vice versa.

Thermodynamic Study for Dibenzo-24-crown-8 Complexes with Alkali Metal Ions in Nonaqueous Solvents

Abstract Complex-formation constants (KML+) of dibenzo-24-crown-8 (DB24C8) with alkali metal ions in acetonitrile and the solubility of DB24C8 in methanol, acetonitrile, and propylene carbonate were determined conductometrically and spectrophotometrically at 25 °C, respectively. The KML+ value sequences of the alkali metal ions with DB24C8 are Na+>Cs+>K+=Rb+. Dibenzo-24-crown-8 shows no remarkable selectivity for the alkali metal ions in acetonitrile. Transfer activity coefficients of the DB24C8 complexes with alkali metal ions were calculated from these data and literature values of transfer activity coefficients of alkali metal ions. For the same alkali metal ion, the bulky DB24C8-alkali metal ion complex is more soluble in the aprotic solvents acetonitrile and propylene carbonate than in the protic solvent methanol as compared with the case of the alkali metal ion itself. The transfer activity coefficient of the DB24C8-alkali metal ion complex from methanol to acetonitrile is somewhat sensitive to the variation of the alkali metal ion in the DB24C8 cavity, whereas the mobility of the DB24C8-alkali metal ion complex at the same concentration in the solvents is not sensitive.