Ion-molecular Interactions Research Articles

Ions with strong symmetric H-bonds and their solvation in aqueous-ethanolic solutions of HCl

Ion-molecular interactions in the HCl-EtOH-H2O system are studied by means of multiple frustrated total internal reflection IR spectroscopy over a wide range of concentrations of the components. It is demonstrated that, in the investigated solutions, the acid is fully bound into ions and uncharged complexes formed by strong symmetric or quasi-symmetric H-bonds. There is a competition between H2O and EtOH molecules during the formation of the (H5C2(H)O…H…O(H)C2H5)+, (H2O…H…OH2)+, and (H2O…H…O(H)C2H5)+ proton disolvates. In dilute solutions of HCl in 2: 1 and 1: 1 EtOH-H2O mixtures, (H2O…H…OH2)+ proton dihydrates are mainly formed, whereas in concentrated HCl solutions, under conditions of a partial solvation of ions by solvent molecules, predominantly (H2O…H…O(H)C2H5)+ mixed proton disolvates arise. In concentrated solutions of HCl in EtOH with low water content, the acid is partially bound into (H5C2(H)O…H+…Cl−) uncharged complexes with the participation of the Cl− anion.

Preparation of fused n-phenyl-substituted pyridinium derivatives by direct phenylation with nucleogenic phenyl cations

The direct phenylation of a nitrogen atom has been carried out for the first time in fused pyridine derivatives by ion-molecular interaction of nucleogenic phenyl cations with acridine and phenanthridine. N-Phenylacridinium and -phenanthridinium compounds, which are sensitive markers for biological investigations, were obtained labeled with tritium.

Pathways of ion–molecular interactions of nucleogenic phenyl cations with the nucleophilic centers of picolines

BackgroundThe nuclear-chemical method brought unique opportunity for synthesis of unknown and hardly available organic compounds. Presence of tritium labeling allows one-step preparation of radioactive markers for the investigation of chemical and biological processes.MethodsThe ion–molecular reactions of nucleogenic phenyl cations with 4-picoline have been carried out. The phenyl cations were generated by spontaneous tritium β-decay within the tritium-labeled benzene. Both additions to the nitrogen and substitutions about the aromatic ring were able to be studied simultaneously.ResultsUnusual substitutions on both the α- and β-positions of the ring system have been revealed.ConclusionBy unknown direct phenylation of nitrogen atom tritium-labeled N-phenylpicolinium derivatives, perspective biological markers have been synthesized.

Antioxidant activity, total phenolic and flavonoid compounds in Prunus mahaleb L. seed

It is difficult to conduct rapid quantitative studies by direct analysis of mass spectrometry because of the matrix effects. In order to overcome the matrix effects in rapid quantitative analysis of complex sample and to find a rapid mass spectrometry method for capsaicin quantitation, the thermal desorption carbon fiber ionization mass spectrometry (TD-CFI-MS) was developed and optimized. TD-CFI-MS allows timesaving, less cost, less solvent consumption and no auxiliary gas. In this method the metal ceramics heater (MCH) was used for analyte desorption. The protonated water clusters in carbon fiber ion source provided proton for analytes through ion-molecular interactions. Desorption and ionization processes were separated in time and space so the analyte was less affected by the matrix during ionization, and the signal intensity of the analyte was enhanced. The matrix effects were investigated by the quantitative analysis of capsaicin in various samples using TD-CFI-MS, and the results were within 93.3–97.6% which indicated that almost no significant effects on the quantitation of capsaicin by this method. Finally, TD-CFI-MS was successfully applied for the quantitation of capsaicin in various real samples including foods and medicines indicating that this technique was a valuable strategy.

Metallic and non-metallic anionic interaction activities estimated with sound velocity and refractive index

Density (ρ±10−3kgm−3), sound velocity (VS±10−2ms−1) as acoustic property and refractive index (μri±10−4) for 0.01–0.1m K2Cr2O7, K2HPO4, KMnO4, KH2PO4, KCl, and KOH aqueous salts with compressibility attained with ion–solvent interaction (ISI) are reported at 0.01 interval and 293.15K. Ionic internal pressure generated with ISI is expressed as adiabatic compressibility (β, pa−1) with relative change (Δβ/β0) and apparent molal compressibility (ϕk, m2N−1) with specific ionic activities for metallic and non-metallic anions. Linear regression generated VS0, μri0, ϕk0, and β0 as limiting data for analysis of speed of light and sound. The VS0 as KH2PO4>K2HPO4>KOH>K2Cr2O7>KCl>KMnO4 denoted a minimum VS0 metallic anions. With concentrations, the sound velocity and refractive index are noted as ISI functions where the sound and light waves were in opposite trends. The Mn0 and Cr0 transitional metals with anions of the K2Cr2O7 and KMnO4 have affected the compressibility as K2Cr2O7>KMnO4 due to 2Cr+6. The VS0, μri0, ϕk0, and β0 analyzed their ionic strengths in comparison to HPO4-, H2PO4-, Cl−, and OH− as non-metallic anions considering the interactions as sensors. A molionic model of ion–water interaction was proposed to generalize ion-molecular interactions in industrial mixtures.

Ion-molecular interactions in solutions of methanesulfonic acid in diethylamine according to IR spectroscopy data

The methanesulfonic acid (MSA)-diethylamine (DEA) binary liquid system is studied over the entire range of compositions at 30°C by using multiple frustrated total internal reflection IR spectroscopy. Solutions with acid: base equimolar ratio contain only 1 : 1 ion pairs. Upon adding the acid, a MSA molecule abstracts an anion from the 1 : 1 complex to produce a protonated DEA and an (H3C(O2)SO…H…OS(O2)CH3)− anion with a strong H bond: (C2H5)2(H)NH+ · OS(O2)CH3− + HOS(O2)CH3 ↔ (C2H5)2(H)NH+ + (H3C(O2)SO…H…OS(O2)CH3)−. This equilibrium is shifted to the left. The 1 : 1 complex is present in solutions even at an significant excess of the acid. To protonate the complex, it is required at least two MSA molecules. Under conditions of an excess of the base, DEA molecules do not solvate the 1 : 1 complex. The solution separates into two phases, composed of (C2H5)2(H)NH+ · OS(O2)CH3− complexes and pure DEA.

Corona Discharge Ion Mobility Spectrometry of Ten Alcohols

Ion mobility spectra for ten alcohols have been studied in an ion mobility spectrometry apparatus equipped with a corona discharge ionization source. Using protonated water cluster ions as the reactant ions and clean air as the drift gas, the alcohols exhibit different product ion characteristic peaks in their ion mobility spectra. The detection limit for these alcohols is at low concentration pmol/L level according to the concentration calibration by exponential dilution method. Based on the measured ion mobilities, several chemical physics parameters of the ion-molecular interaction at atmosphere were obtained, including the ionic collision cross sections, diffusion coefficients, collision rate constants, and the ionic radii under the hard-sphere model approximation.

Ion-molecular interactions in the methylsulfonic acid—methanol system according to the IR spectral data

The methylsulfonic acid (MSA)—methanol (MeOH) liquid binary system was studied over the whole concentration range by the MBTIR IR spectroscopy method at 30°C. Quasi-ion pairs with the 1: 1 composition formed by a strong symmetrical H-bond were only present in solutions with an equimolar acid: base ratio. The addition of methanol caused the solvation of quasi-ion pairs by MeOH molecules, and, in the presence of the base in a substantial excess (CMeOH0: CMSA0 > 2), proton disolvates (Me(H)O⋯H⋯O(H)Me)+ with strong symmetrical H-bonds were formed; that is, there was B⋯H⋯A + B ↔ (B⋯H⋯B)+ + A− equilibrium, where B is the base molecule and HA is the acid. In the presence of excess acid, methanol was protonated, and negatively charged proton disolvates were formed, B⋯H⋯A + HA ↔ BH+ + (AHA)−. This equilibrium was fully shifted to the right.

Interionic interactions in alcoholic solutions of hydrogen halides

The experimental ionization constants were used to calculate and analyze the effective short-range potential dij for HCl, HBr, and HI in n-alcohols from methanol to octanol at 5–55°C. Changes in the dij and ΔijG* = NAdij values depending on temperature, solvent, and anions were explained in terms of the Samoilov concept of short-range solvation. The character of changes in ΔijG* was shown to be determined by the ratio between the contributions of ion-molecular and intermolecular non-Coulomb interactions, which were, in turn, determined by the structural state of the solvent and solvation of electrolyte particles in solutions of hydrogen halides.

Cluster structures determined by ion–molecular interactions: preferential solvation and acid–base neutralization

The neutralization of CH 3COOH by NaOH in water has been studied by the mass spectrometric analysis of clusters generated via fragmentation of liquid droplets. In water, CH 3COOH molecules form self-association clusters at higher acid concentrations like the molar ratio of CH 3COOH:H 2O=1:10. At these concentrations, the neutralization takes place via interaction between the CH 3COOH clusters and NaOH to afford Na +(CH 3COOH) a(CH 3COONa) b clusters. Furthermore, Na + is preferentially solvated by CH 3COOH in water to form Na +(CH 3COOH) α clusters. In consideration with these cluster structure, the reaction mechanism in solution can be realized more precisely.

Electroconduction, Association, and Ion–Molecular Interactions in Nickel Chloride Solutions in Methanol at 5–55°C

Results of a conductimetric investigation of nickel chloride in methanol at 5–55°C and electrolyte concentrations of 0.1–5 mM are presented. Limiting equivalent conductivities by Ni2+ and Cl− and constants of ionic association in the first step with the formation of ionic pair NiCl+ are determined for asymmetric electrolytes using an extended Lee–Wheaton equation. In dilute nickel chloride solutions in methanol the association of ions in the second step is inessential. The size of dynamic solvation sheaths of the ions and the short-range non-coulombic interion potential suggest that the Ni2+ ion forms a kinetically and energetically stable solvated complex with the nearest solvation layer being ∼400 pm thick and virtually temperature-independent. The nearest kinetically stable solvation sheath of the Cl− ion comprises mostly hydroxyl groups of methanol molecules and its stability is severely dependent on temperature.

Collective Motion of Charges in Lithium Tetrafluoroborate Solutions in Acetonitrile

The spectra (cosine Fourier transform) of autocorrelation functions of a microscopic current and their components in lithium tetrafluoroborate solutions in acetonitrile at concentrations of up to 0.75 M are studied by molecular dynamic modeling. The contributions of molecules (M), cations (Kt), and anions (An) to the overall spectrum are determined. The latter is presented as the sum of series of components (MM, MKt + KtM, MAn + AnM, KtKt, KtAn + AnKt, AnAn). The maximums in the MM component at 14 THz and KtKt component at 55 THz are related to IR bands in the spectrum. A negative peak is observed in the (KtAn + AnKt) component at 4 THz. A “microscopic” interpretation is provided for relevant spectra in the terms of intermolecular and ion–molecular interactions. The link between the spectra of the current autocorrelation functions and the nature of ionic association is explained.

H+5 cluster ion and its neutral products H3 and H4

The experimental results for H+5 cluster ions are reported . The formation an d dissociation of H+5 cluster ions were discussed. Accord ing to theory, sta ble H+n cluster ions may be formed by H+3 core with one or more H 2 molecule. On the other hand, there exist conditions for the reactio n of H+3 and H2 in a rf ion source. In the experiments, the ion beam was accelera ted by van de Graff and selected by 90° analysis magnet in the condition of cur rent for mass number 5, and then diffracted by 20° analysis magnet, the energy spectrum of ion beam was obtained. From the spectrum, it is found that H+5 cluster ions may be formed from the ion-molecular interaction between H+3 ion and H2 neutral molecule in rf ion source and that there may exist H3 and H4 neutral clusters among the products of H+5 c luster ions.

Acid-base interactions in the dichloroacetic acid-ethyl acetate system according to IR spectroscopic data

The method of multiple total internal reflection infrared spectroscopy (MTIRIRS) is used to study ion–molecular interactions in the system dichloroacetic acid–ethyl acetate in the range of concentrations from pure acid to pure base at 30°C. Depending on the ratio of components in the solution, molecular complexes with acid : base ratios of 1 : 1 or 2 : 1 are formed in the solutions. In the case of excess acid, base is not protonated and species with a strong symmetric hydrogen bond are not formed. It is shown that the absorption coefficient near 2000 cm–1 can be used to judge the type of the complex formed and the strength of a hydrogen bond in molecular complexes.

IR study of ion-molecular interactions in the system methanesulfonic acid-ethyl acetate

The complex formation in the methanesulfonic acid (MSA)—ethyl acetate (EA) system was studied by Multiple Attenuated Total Reflection (MATR) IR spectroscopy at 30°C. In solutions with excess EA, neither protonation of a base nor formation of complexes with a strong symmetrical H bond was observed. Molecular complexes EA·MSA are found in these solutions. Complexes formed by the strong symmetric H bond are observed in the system when the MSA content exceeds 50 mol.%

INTERIONIC AND INTERMOLECULAR INTERACTIONS IN ION-EXCHANGE AND SORPTION SYSTEMS INVOLVING PHYSIOLOGICALLY ACTIVE SUBSTANCE

ABSTRACT This paper reviews the results obtained by studying the sorption of physiologically active substances (PAS) of different types such as, amino acids, nucleotides and melanoidins on ion exchangers and non-ionogenic sorbents. The review is mainly focused upon die mechanisms of interaction of PAS molecules in the sorbent phase. The contribution of ion-ionic, ion-molecular and intermolecular interactions to the overall sorption effect is discussed. The results of studying ion-exchange isothermal supersaturation of amino acid solutions on anion exchangers are reported and discussed. The mechanisms of aging of ion-exchange materials in the course of recovery of PAS from fermentation broths and hydrolysates are proposed.

Ions with a strong symmetrical H bond in the HCl−BuiOH system by IR spectroscopy data

Ion-molecular interactions in the HCl−BuiOH system with different compositions (from neat isobutyl alcohol to 37 mol.% HCl) were studied by Multiple Attenuated Total Reflectance (MATR) IR spectroscopy at 30 °C. Proton disolvates (Bui(H)O…H…O(H)Bui)+ with strong symmetrical H bonds are formed upon the addition of HCl to BuiOH. At high concentrations of HCl (C 0 HCl>33 mol.%), (Cl…H…Cl)− ions are formed along with (BuiOH)2H+. The spectra of positively and negatively charged proton disolvates were compared to those of similar ions in the HCl−PriOH and HCl−MeOH systems.

IR spectroscopic study of ion-molecular interactions in the methanesulfonic acid—N,N-dimethylformamide system

Complex formation in the methanesulfonic acid (MSA)-DMF system was studied by Multiple Attenuated Total Reflectance (MATR) IR spectroscopy at 30°C within the composition range from neat MSA up to neat DMF. Depending on the ratio of components, two types of complexes with a strong quasi-symmetrical H bond (1 and2) are formed. The uncharged complex1 is a quasi-ion pair with the (O…H…O) bridge. Complex2 is formed by a protonated DMF molecule and the (A…H…A)− anion bound as an ion pair. It is established that complexes1 are solvated by DMF molecules in an excess of a base. Solvation or2 in an excess of an acid corresponds to a change from contact to contact-separated ion pairs. Continuous absorption spectra of charged and uncharged complexes1 and2 were obtained. The schemes of acid-base interactions in the MSA-DMF and HCl-DMF systems were compared.

Structure and Dynamics of Ion-Molecular Interactions in 1–1 Electrolyte Solutions in Dimethylformamide on the Temperature Range 25–70°C from Viscosity and Density Data

Structure and Dynamics of Ion-Molecular Interactions in 1–1 Electrolyte Solutions in Dimethylformamide on the Temperature Range 25–70°C from Viscosity and Density Data

Ion-molecular interactions and the equilibrium composition in the HCl-1-methyl-2-pyrrolidone-1,1,2,2-tetrachloroethane system according to IR spectroscopy data

Multiple Attenuated Total Reflectance (MATR) IR spectra of solutions of HCl in 1-methyl-2-pyrrolidone (N-MP) (0–43.4 % HCl) were studied in the 900–4000 cm−1 range. Spectra were recorded for theN-MP-HCl-1,1,2,2-tetrachloroethane (TCE) ternary system at a TCE ∶N-MP ratio of 1 ∶ 1. Depending on the ratio between the components, complexes of the compositionN-MP · HCl (C-1),N-MP · 2HCl (C-2), and 2N-MP · HCl (C-3) are formed in the system. Complex C-1 has a quasiionic structure, (CH2)3N(Me)CO...H...Cl, formed by a strong quasisymmetrical H-bond between the carbonyl O atom and the Cl atom. The addition of anN-MP molecule to complex C-1 yields complex C-3, in which the quasiionic character of the bond betweenN-MP and HCl is retained. When excess HCl is present, the quasiionic structure is destroyed, theN-MP molecule is protonated, and the Cl− anion interacts with HCl to give an ion with a strong symmetrical H bond (Cl...H...Cl)−. Complex C-2 is an ion pair.