Conductance, a Contrivance To Explore Ion Association and Solvation Behavior of an Ionic Liquid (Tetrabutylphosphonium Tetrafluoroborate) in Acetonitrile, Tetrahydrofuran, 1,3-Dioxolane, and Their Binaries

Investigation of intermolecular interactions of l-Valine and l-Phenylalanine with muscle relaxant drug mephenesin molecule prevalent in aqueous solution by various physico-chemical methods at T=298.15K-313.15K

A complete chemical analysis of significant intermolecular interactions of l-Valine (L-Val) and l-Phenylalanine (L-Phe) with Mephenesin (MEPN) molecules in aqueous solution has been studied by different physicochemical methodologies at various temperatures (T = 298.15 K-313.15 K at an interval of 5 K) and concentrations (0.001 mol kg-1, 0.003 mol kg-1, 0.005 mol kg-1) of aqueous MEPN solution. The limiting apparent molar volume (φ V 0 ) and experimental slope (S V * ) values are found from the equation of Masson, viscosity A and B-coefficient determined using the equation of Jones-Doles, molar refraction (RM) and limiting molar refraction (RM0) derived by the Lorentz-Lorenz equation, express that in our experimental solution of amino acids (AAs) in aqueous MEPN, the solute-solvent interaction predominates over the solute-solute and solvent-solvent interactions for these ternary solutions. These are also justified by the measurement of various thermodynamic parameters, free energy of activation of viscous flow per mole of solvent(Δμ1°#) and solute (Δμ2°#), activation of viscous flow of enthalpies (ΔH°#) and entropies (ΔS°#). The characteristics of structure-breaking of solutes in the aqueous drug solution have been identified by Hepler's method and dB/dT value. The spectroscopic methods like UV-visible and proton-NMR studies help to explicate the strong AA-MEPN interactions in the solution phase and obtain a good correlation with theoretical studies. Theoretical investigations are checked to authenticate the experimental observations and according to both studies, L-Phe-MEPN interaction is greater than L-Val-MEPN interaction. The experimental and correlated research data are useful for the development of model combinations of AAs with drug molecules in pharmaceutical and medicinal chemistry.

Exploration of Diverse Interactions of l-Methionine in Aqueous Ionic Liquid Solutions: Insights from Experimental and Theoretical Studies

Here, we have investigated some physicochemical parameters to understand the molecular interactions by means of density (ρ) measurement, measurement of viscosity (η), refractive index(n _D) measurement, and conductance and surface tension measurements between two significant aqueous ionic liquid solutions: benzyl trimethyl ammonium chloride (BTMAC) and benzyl triethyl ammonium chloride (BTEAC) in an aqueous l-methionine (amino acid) solution. The apparent molar volume (Φ_v), coefficient of viscosity (B), and molar refraction (R _M) have been used to analyze the molecular interaction behavior associated in the solution at various concentrations and various temperatures. With the help of some important equations such as the Masson equation, the Jones-Doles equation, and the Lorentz-Lorenz equation, very significant parameters, namely, limiting apparent molar volumes (Φ_v ⁰ ), coefficient of viscosity (B), and limiting molar refraction (R _M ⁰), respectively, are obtained. These parameters along with specific conductance (κ) and surface tension (σ) are very much helpful to reveal the solute-solvent interactions by varying the concentration of solute molecules and temperature in the solution. Analyses of Δμ₁ ^0#, Δμ₂ ^0#, TΔS ₂ ^0#, ΔH ₂ ^0#, and thermodynamic data provide us valuable information about the interactions. We note that l-Met in 0.005 molality BTEAC ionic liquid at 308.15 K shows maximum solute-solvent interaction, while l-Met in 0.001 molality BTMAC aqueous solution of ionic liquid at 298.15 K shows the minimum one. Spectroscopic techniques such as Fourier transform infrared (FTIR), ¹H-NMR, and UV-vis also provide supportive information about the interactions between the ionic liquid and l-methionine in aqueous medium. Furthermore, adsorption energy, reduced density gradient (RDG), and molecular electrostatic potential (MESP) maps obtained by the application of density functional theory (DFT) have been used to determine the type of interactions, which are concordant with the experimental observations.

Superalkali-Alkalide Interactions and Ion Pairing in Low-Polarity Solvents

The nature of anionic alkali metals in solution is traditionally thought to be "gaslike" and unperturbed. In contrast to this noninteracting picture, we present experimental and computational data herein that support ion pairing in alkalide solutions. Concentration dependent ionic conductivity, dielectric spectroscopy, and neutron scattering results are consistent with the presence of superalkali-alkalide ion pairs in solution, whose stability and properties have been further investigated by DFT calculations. Our temperature dependent alkali metal NMR measurements reveal that the dynamics of the alkalide species is both reversible and thermally activated suggesting a complicated exchange process for the ion paired species. The results of this study go beyond a picture of alkalides being a "gaslike" anion in solution and highlight the significance of the interaction of the alkalide with its complex countercation (superalkali).

ESI activity of Br⁻, BF₄⁻ , ClO₄⁻ and BPh₄⁻ anions in the presence of Li⁺ and NBu⁴⁺ counter-ions

To improve our understanding of the electrospray ionization (ESI) process, we have subjected equimolar mixtures of salts A⁺ X^- (A⁺  = Li⁺ , NBu₄⁺ ; X^-  = Br^- , ClO₄^- , BF₄^- , BPh₄^- ) in different solvents (CH₃ CN, tetrahydrofuran, CH₃ OH, H₂ O) to negative-ion mode ESI and analyzed the relative ESI activity of the different anionic model analytes. The ESI activity of the large and hydrophobic BPh₄^- ion greatly exceeds that of the smaller and more hydrophilic anions Br^- , ClO₄^- and BF₄^- , which we ascribe to its higher surface activity. Moreover, the ESI activity of the anions is modulated by the action of the counter-ions and their different tendency toward ion pairing. The tendency toward ion pairing can be reduced by the addition of the chelating ligands 12-crown-4 and 2.2.1 cryptand and is, although to a smaller degree, further influenced by the variation of the solvent. Complementary electrical conductivity measurements afford additional information on the interactions of the ionic constituents of the sample solutions. Copyright © 2017 John Wiley & Sons, Ltd.

Probing Inclusion Complex Formation of Amantadine Hydrochloride with 18-Crown-6 in Methanol by Physicochemical Approach

The complex formation of amantadine hydrochloride with 18-crown-6 was studied in methanol solution by surface tension, conductivity and IR study. The limiting apparent molar volume data have been used to characterize the interaction between drug molecule (amantadine hydrochloride) and 18-crown-6 in the experimental ternary solution systems. A conductance study concerning the interaction between cationic organic ammonium ions amantadine with 18-crown-6 in methanol solution has been carried out at different temperatures. The formation constant (logK f ) of the resulting 1:1 complex at various temperatures was determined from the conductivity study. The enthalpy (ΔH 0) entropy (ΔS 0) and free energy change (ΔG 0) of the complexation reaction was determined from the temperature dependence of the formation constant.

Hollow circular compound-based inclusion complexes of an ionic liquid

Inclusion complex formation between hollow circular compounds, e.g. crown ethers, and an ionic liquid, 1-methyl-3-octylimidazolium tetrafluoroborate, in acetonitrile solvent is studied by means of conductivity measurements, IR and NMR spectra.

Investigation of an inclusion complex formed by ionic liquid and β-cyclodextrin through hydrophilic and hydrophobic interactions

An investigation of the inclusion behavior of a guest ionic liquid (IL) 1-methyl-3-octylimidazolium tetrafluoroborate into the host cavity of β-cyclodextrin in aqueous solution has been carried out towards modern research to gain a far reaching effect.

Study to explore assorted interfaces of an ionic liquid prevailing in solvent systems by physicochemical approach

Trends in solvation of the ionic liquid [bupy]Br in various solvents have been investigated: 1,4 DO (pink), THF (blue) and ACN (yellow).

Study of ion-pair and triple-ion origination of an ionic liquid ([bmmim][BF4]) predominant in solvent systems

Electrolytic conductivities, densities, viscosities, and FT-IR spectra of 1-butyl-2,3 dimethylimidazolium tetrafluoroborate ([bmmim][BF₄]) have been studied in tetrahydrofuran, dimethylacetamide and methyl cellosolve at different temperatures.

Quantitative and qualitative analysis of ionic solvation of individual ions of imidazolium based ionic liquids in significant solution systems by conductance and FT-IR spectroscopy

Exploration of significant interactions in eco-friendly RTILs in some liquid systems with a wide range of applications.