Ionic Parts Research Articles

Design of V-shaped ionic liquid crystals: atropisomerisation ability and formation of double-gyroid molecular assemblies.

We designed V-shaped ionic liquid crystals with two sterically congested ionic parts at the vertex. Depending on the degree of steric hindrance, atropisomerisation occurred in solution. All compounds formed bicontinuous cubic phases with double-gyroid structures in the bulk state, partially owing to the co-existence of atropisomers with opposite chirality.

Nanoparticles based Strategies for Treating and Managing Battle against Malaria: An Overview

Malaria is a life-threatening disease spread via female Anopheles mosquitoes. Assortments of factors are causing the trouble i.e., (i) fierce opposition posed by the plasmodium life cycle and intracellular localization for pathogens in hepatocytes and erythrocytes; (ii) The decisive physical and chemical properties among most antimalarial drugs, that exhibit an amphiphilic property allowing them to be widely circulated in and out of body tissues since administration and quickly fully exploited in the liver; (iii) The unflattering fluidic circumstances confronted in blood flow that affect the relationship of ionic parts to target tissue. So rather than concentrating the entire energy on establishing novel medications, it is preferable to effort into refining operative medicine conveyance transporters to overcome these downsides. Anti-paludism medications have been effectively distributed via nanomaterials on adjacent concentrations high sufficient on the way to slay the pests and evade the growth of treatment obstruction, although upholding a small general amount to foil uncomplimentary poisonous sideways things. As of now, a few nanostructured frameworks like liposomes or dendrimers have been demonstrated to be fit for working on the viability of anti-malarial treatments. These nanoparticles are an auspicious medication conveyance automobile and could be utilized as remedial techniques intended for battling pests. This audit is expected to scrutinize the utilization of nanoparticles to further develop medicine effectiveness at various phases for both human and vampire congregations of miasm vermin.

Protein Cryoprotectant Ability of the Aqueous Zwitterionic Solution.

Protein cryopreservation is important for the long-term storage of unstable proteins. Recently, we found that N-acetylglucosaminyltransferase-V (GnT-V) can be cryopreserved in a deep freezer without temperature control using a dilute binary aqueous solution of 3-(1-(2-(2-methoxyethoxy)ethyl)imidazol-3-io)butane-1-carboxylate (OE2imC3C) [10 wt %, mole fraction of solute (x) = 7.75 × 10-3], an artificial zwitterion. However, it is unclear which solvent properties are required in these media to preserve unstable proteins, such as GnT-V. In this study, we investigated the melting phenomena and solution structure of dilute binary aqueous OE2imC3C solutions [x = 0-2.96 × 10-2 (0-30 wt %)] using differential scanning calorimetry (DSC) and Raman and Fourier transform infrared (FTIR) spectroscopies combined with molecular dynamics (MD) simulation to compare the cryoprotectant ability of OE2imC3C with two general cryoprotectants (CPAs), glycerol and dimethyl sulfoxide. DSC results indicated that aqueous OE2imC3C solutions can be melted at lower temperatures with less energy than the control CPA solution, with increasing x, primarily due to OE2imC3C having a higher content of unfrozen water molecules. Moreover, Raman and FTIR results showed that the high content of unfrozen water molecules in aqueous OE2imC3C solutions was due to the hydration around the ionic parts (the COO- group and imidazolium ring) and the OCH2CH2O segment. In addition, the MD simulation results showed that there were fewer structured water molecules around the OCH2CH2O segment than the hydration water molecules around the ionic parts. These solvent properties suggest that dilute aqueous OE2imC3C solutions are effective in preventing freezing, even in a deep freezer. Therefore, this medium has the potential to act as a novel cryoprotectant for proteins in biotechnology and biomedical fields.

Exploring of spacer fluorination effect on the characteristics and physicochemical properties of the newly designed task specific dicationic imidazolium-based ionic liquids: A quantum chemical approach

Forming possibility of two series of DILs based on the 1,4-bis(4-methyl-imidazolium) p-phenyl ([p-C6H4(MIM)2]2+ = [PHIM]2+) and 1,4-bis (4-methyl- imidazolium) p-1,1′-perfluoro- phenyl ([p-C6F4(MIM)2]2+= [PFIM]2+) dications and [Y1]− = [CH3CO2]−, [Y2]− = [NO3]−, [Y3]− = [CF3CO2]−, [Y4]− = [BF4]−, [Y5]− = [ClO4]− and [Y6]− = [PF6]− anions were explored using quantum computational methods. The roles of anion exchange as well as fluorination of the spacer group (phenyl ring) on the physicochemical properties of the designed DILs ([PHIM][Y1-6]2 and [PFIM][Y1-6]2) were evaluated. The potential electrostatic curves, values of interaction thermodynamic energies, structural parameters, topological properties, natural charge of atoms, charge transfer (CT) and charge transfer energy (E(2)) of acceptor-donor interactions, reduced gradient density (RGD) plots, and electrochemical windows (ECW) were examined. The obtained corrected interaction energies for [PHIM][Y1-6]2 DIL series are ranging from -256.44 to -214.83 kcal mol−1 and those are for [PFIM][Y1-6]2 DILs are ranging from -265.12 to -221.85 kcal mol−1. The results indicate that the DILs based on CH3CO2−, NO3− and CF3CO2− anions form stronger hydrogen bonds with the dications. The strength of the interactions between ionic constructing parts in [PFIM][Y1-6]2 DILs are about 6.04 -10.28 kcal mol−1 more than the [PHIM][Y2-6]2 DILs analogues. Nature of the hydrogen bond interactions between ionic parts in most of the [PHIM][Y1,2]2 and [PFIM][Y1-3]2 DILs determined as electrostatic interaction. The order of changes in some macroscopic properties such as melting point, critical temperature, enthalpy of vaporization, electrical conductivity, viscosity and electrochemical stability of the studied DILs were estimated stand on the calculated intermolecular interaction energies. Results showed, DILs that their cathodic and anodic stability controlled by their corresponding dications (such as: [PHIM][Y4,6]2 and [PFIM][Y4,6]2), have higher ECW values in comparison to the others.

CENT2: Improved charge equilibration via neural network technique

The high computational cost of first-principles electronic structure methods together with the successful applications of machine learning (ML) techniques in atomistic simulations resulted in a surge of interest in ML-based interatomic potentials. Despite great progress in the field, there remain some challenges to be solved such as the best way of incorporating long-range interactions, as well as nonlocal charge transfer. The first generation of the charge equilibration via neural network technique (CENT) was a major step forward in concurrently taking into account both aforementioned points. Within structure prediction methods, it turned out to be a powerful tool in discovering novel polymorphs of ionic systems. On the other hand, the method is not expected to be appropriate for multicomponent systems with reference data sets in which some or all elements are subject to varying oxidation states. Here, we present the second generation of CENT, with multiple improvements to the original variant that lead to a more accurate treatment of electrostatic interactions. To do this, it aims at reproducing the electric potential function, which is directly related to the charge distribution, rather than only considering total energies. In addition, a charge-free term is added to correct for the difference between the reference energies and those obtained with the energy functional of CENT. Moreover, the Green's function within the Hartree energy is modified to substantially shield interactions from charges in the neighborhood of each point. Also, the charge density is split into ionic and electronic parts, which allows for a better approximation of the electron density. The utility of this method is examined for magnesium oxide clusters, and multiple comparisons with the first generation are made, demonstrating that much more physical electrostatic interactions can be expected from the second generation of CENT.

Electrical properties of ceramics based on Ag7TS5I (T = Si, Ge) solid electrolytes

The ceramic samples based on the synthesized compounds of Ag7TS5I (T ​= ​Si, Ge) solid electrolytes were prepared with using of micro- and nanocrystalline powders. Structural studies of powders obtained by grinding in an agate mortar as well as in a planetary ball mill were carried out by XRD and SEM techniques. Optical microscopy was used to estimate the size of crystallites after annealing of prepared ceramics. Temperature (292–383 ​K) and frequency (10 ​Hz–2 ​× ​106 ​Hz) dependences of total electrical conductivity of ceramic samples were investigated by impedance spectroscopy technique. Separation of electronic and ionic parts of electrical conductivity were carried out by the analysis of Nyquist plots using electrode equivalent circuits. The dependences of ionic and electronic components of the electrical conductivity on temperature and on average size of the crystallites were investigated for Ag7TS5I-based ceramics. The comparison of electrical parameters for Ag7TS5I (T ​= ​Si, Ge) crystals, composites and ceramics was performed.

Negative Piezoelectric Coefficient in Ferromagnetic 1H-LaBr2 Monolayer.

The discovery of two-dimensional (2D) magnetic materials that have excellent piezoelectric response is promising for nanoscale multifunctional piezoelectric or spintronic devices. Piezoelectricity requires a noncentrosymmetric structure with an electronic band gap, whereas magnetism demands broken time-reversal symmetry. Most of the well-known 2D piezoelectrics, e.g., 1H-MoS2 monolayer, are not magnetic. Being intrinsically magnetic, semiconducting 1H-LaBr2 and 1H-VS2 monolayers can combine magnetism and piezoelectricity. We compare piezoelectric properties of 1H-MoS2, 1H-VS2, and 1H-LaBr2 using density functional theory. The ferromagnetic 1H-LaBr2 and 1H-VS2 monolayers display larger piezoelectric strain coefficients, namely, d11 = −4.527 pm/V for 1H-LaBr2 and d11 = 4.104 pm/V for 1H-VS2, compared to 1H-MoS2 (d11 = 3.706 pm/V). 1H-MoS2 has a larger piezoelectric stress coefficient (e11 = 370.675 pC/m) than 1H-LaBr2 (e11 = −94.175 pC/m) and 1H-VS2 (e11 = 298.100 pC/m). The large d11 for 1H-LaBr2 originates from the low elastic constants, C11 = 30.338 N/m and C12 = 9.534 N/m. The sign of the piezoelectric coefficients for 1H-LaBr2 is negative, and this arises from the negative ionic contribution of e11, which dominates in 1H-LaBr2, whereas the electronic part of e11 dominates in 1H-MoS2 and 1H-VS2. We explain the origin of this large ionic contribution of e11 for 1H-LaBr2 through Born effective charges (Z11) and the sensitivity of the atomic positions to the strain (du/dη). We observe a sign reversal in the Z11 values of Mo and S compared to the nominal oxidation states, which makes both the electronic and ionic parts of e11 positive and results in the high value of e11. We also show that a change in magnetic order can enhance (reduce) the piezoresponse of 1H-LaBr2 (1H-VS2).

Exploration of physico-chemical properties of aspirin as pharmaceutical waste in aqueous environment by acoustic method

The presence of pharmaceutical wastes has been detected in various water environments. These pharmaceutical pollutants may lead to serious problems to human and animal health. Various molecular interactions existing in aqueous drug systems may be considered responsible for these health hazards. For the present investigation density and acoustic properties of the solutions with different drug concentrations were measured at 298.15 K. Various mathematical relations were used to derive a number of physico-chemical parameters including isentropic compressibility (KS), apparent molar isentropic compressibility KS,ϕ, isothermal compressibility (KT), intermolecular free length (Lf), molar free volume (Vf), internal pressure (πi), acoustic impedance (Z), relative association (RA) and surface tension (S). In an attempt to understand the interactions between ionic, hydrophilic and hydrophobic parts of drug fragments present in the ternary solutions and the structural effects of the solute on the solvent, a thorough analysis of these parameters were done. A conclusion can be drawn that the structure making properties of the drug molecules play an important role and solute–solvent interactions are prevalent in these systems.

Luminescent Ionic Liquid Crystals Based on Naphthalene‐Imidazolium Unit

AbstractIn this article, we describe an efficient synthetic pathway and the characterization of liquid crystal luminescent imidazolium salts based on a naphthalene unit. The luminescent imidazolium‐naphthalene rigid part is decorated with a benzyl group functionalized by two or three dodecyloxy chains. A crystalline structure shows unambiguously the segregation between the rigid ionic and flexible parts conducive to the emergence of mesomorphic properties. A complete thermotropic properties study of these salts has been carried out according to different anions. The alkyl tail number variation and therefore the amphipathic character (balance between hydrophilic/hydrophobic) makes it possible to induce liquid crystal state with different architectures of self‐organization in layers (Smectic A) or columns (Columnar hexagonal). Finally, the photophysical properties were measured in solution and in the solid state at room temperature and showed photoluminescence quantum yields around 20 %.

Sorting droplets into many outlets.

Droplet microfluidics is a commercially successful technology, widely used in single cell sequencing and droplet PCR. Combining droplet making with droplet sorting has also been demonstrated, but so far found limited use, partly due to difficulties in scaling manufacture with injection molded plastics. We introduce a droplet sorting system with several new elements, including: 1) an electrode design combining metallic and ionic liquid parts, 2) a modular, multi-sorting fluidic design with features for keeping inter-droplet distances constant, 3) using timing parameters calculated from fluorescence or scatter signal triggers to precisely actuate dozens of sorting electrodes, 4) droplet collection techniques, including ability to collect a single droplet, and 5) a new emulsion breaking method to collect aqueous samples for downstream analysis. We use these technologies to build a fluorescence based cell sorter that can sort with high (>90%) purity. We also show that these microfluidic designs can be translated into injection molded thermoplastic, suitable for industrial production. Finally, we tally the advantages and limitations of these devices.

Double-Gyroid Nanostructure Formation by Aggregation-Induced Atropisomerization and Co-Assembly of Ionic Liquid-Crystalline Amphiphiles.

We report a new molecular‐design principle for creating double‐gyroid nanostructured molecular assemblies based on atropisomerization. Ionic amphiphiles containing two imidazolium rings close to each other were designed and synthesized. NMR data revealed that the rotation of the imidazolium rings is restricted, with an activation energy as high as 63 kJ mol−1 in DMSO‐d6 solution (DFT prediction for a model compound in the vacuum: 90–100 kJ mol−1). Due to the restricted rotation, the amphiphiles feature “double” atropisomeric axes in their ionic segments and form three stable atropisomers: meso, R, and S. These isomers co‐organize into Ia3‾d ‐type bicontinuous cubic liquid‐crystalline mesophases through nanosegregation of the ionic and non‐ionic parts. Considering the intrinsic characteristic of Ia3‾d ‐type bicontinuous cubic structures that they are composed of intertwined right‐ and left‐handed single gyroids, we propose that the simultaneous presence of both R‐ and S‐atropisomers is an important contributor to the formation of double‐gyroid structures.

First time investigation of the substitution effect at anion part of the ILs on their physicochemical properties using [DMT][4-XPhSO3] (X=NH2, OH, H, F, Br, CHO, CF3, CN and NO2) as a model ILs: A systematic DFT study

Abstract In this study, a different class of high nitrogen content ionic liquids were designed. The physicochemical properties of [DMT][4-XPhSO3], (X = NH2, OH, H, F, Br, CHO, CF3, CN and NO2) IPs based on the triazolium cation and substituted benzene sulfonate anions were fully investigated using M06–2X functional in conjunction with the aug-ccpvdz basis set. For all of the designed ILs the structural parameters, interaction energy between constructing parts, enthalpy of formation, natural charges and topological properties were calculated and discussed. The effect of the substituent change at anion part on the interaction energy and physicochemical properties is taking into account for the first time. As revealed from the results, the strength of the interaction between constructing ionic parts had a linear correlation with the electron content of the anionic part in a way that the more stable ion pairs with higher interaction energies constructed as the electron content of the anionic part increased. Melting point, critical-point temperature, electrochemical stability and conductivity which are some of the important IL,s characteristic physical properties were estimated, compared with each other and discussed with the help of the quantum chemical computationally obtained thermochemical data for nine designed various X substituted [DMT][4-XPhSO3] ILs. Finally, the enthalpy and Gibbs free energy of the formation for nine various substituted anions were calculated.

Design of Ionic Liquid Crystals Forming Normal-Type Bicontinuous Cubic Phases with a 3D Continuous Ion Conductive Pathway

We have prepared a series of pyridinium-based gemini amphiphiles. They exhibit thermotropic liquid–crystalline behavior depending on their alkyl chain lengths and anion species. By adjusting the alkyl chain lengths and selecting suitable anions, we have obtained an ionic amphiphile that exhibits a normal-type bicontinuous cubic phase from 38 °C to 12 °C on cooling from an isotropic phase. In the bicontinuous cubic liquid–crystalline assembly, the pyridinium-based ionic parts align along a gyroid minimal surface forming a 3D continuous ionic domain while their ionophobic alkyl chains form 3D branched nanochannel networks. This ionic compound can form homogeneous mixtures with a lithium salt and the resultant mixtures keep the ability to form normal-type bicontinuous cubic phases. Ion conduction measurements have been performed for the mixtures on cooling. It has been revealed that the formation of the 3D branched ionophobic nanochannels does not disturb the ion conduction behavior in the ionic domain while it results in the conversion of the state of the mixtures from fluidic liquids to quasi-solids, namely highly viscous liquid crystals. Although the ionic conductivity of the mixtures is in the order of 10–7 S cm–1 at 40 °C, which is far lower than the values for practical use, the present material design has a potential to pave the way for developing advanced solid electrolytes consisting of two task-specific nanosegregated domains: One is an ionic liquid nano-domain with a 3D continuity for high ionic conductivity and the other is ionophobic nanochannel network domains for high mechanical strength.

Structure and electrical conductivity of Ta doped La2Mo2O9 oxide ion conductors

In this work, we have investigated the crystal structure, thermal, vibrational, microstructural, and electrical properties of Ta doped La2Mo2O9 oxide ion conductors. The Rietveld refinements on the X-ray diffraction patterns confirm the α phase similar to that of undoped La2Mo2O9 at room temperature. α → β phase transition is confirmed by the differential scanning calorimetry analysis. The microcrystalline samples have grain sizes ∼10 μm along with well-defined grain boundaries. The infrared and Raman spectra mainly consist of MoO4 bands. The electrical conductivity of the highly dense pellets was analyzed by the impedance spectroscopy genetic programming method coupled with distribution function of relaxation times (DFRTs). Each DFRT consists of three main peaks conferring bulk, ionic, and electronic contributions of the grain boundary. The higher oxide ion conductivity in the β phase is identified due to the electronic contribution of the grain boundary for the samples. The capacitance for bulk and ionic parts of the grain boundary are almost temperature independent, whereas the electronic contribution varies turbulently. The incorporation reaction suggests that the sample with 5 wt. % Ta has the maximum oxide ion conductivity, which is further verified by the resistances obtained from the DFRT analysis.

Adsorption and Photocatalytic Degradation of Anionic and Cationic Surfactants on Nitrogen‐Modified TiO2

AbstractAdsorption and photocatalytic decomposition of anionic and cationic surfactants are presented. Two different types of photocatalysts were studied, commercial TiO2‐P25 (Evonik) with pHpzc = 5.65 and nitrogen‐modified TiO2/N pHpzc = 6.7 (point of zero charge). Two different types of surfactants were used: anionic surfactant NaDBS (sodium dodecylbenzene sulfonate) and cationic surfactant BtCl (benzethonium chloride). Obtained adsorption isotherms of NaDBS and BtCl comply with the conditions of monolayer Langmuir model isotherms. The maximal anionic surfactant adsorption took place at acidic pH and it was higher for TiO2/N (196 mg g−1) than for commercial TiO2‐P25 (140 mg g−1). There was the opposite situation in the case of cationic surfactants, higher adsorption took place at alkaline condition and it was higher for TiO2/N (100 mg g−1) than for commercial TiO2‐P25 (85 mg g−1). Photocatalytic degradation has been found to be more effective in neutral and high than in low pH solutions for both surfactants. It is mainly the difference between charges of the surface of photocatalysts and ionic parts of individual surfactants that determined the effectiveness for each of them.

Anodic TiO2 nanotubes produced under atmospheric pressure and in vacuum conditions

Throughout the intense research of anodic TiO2 nanotubes (ATNTs), the effect of ambient pressure is usually ignored. In this article, Ti foils were potentiostatically anodized both under atmospheric pressure (0.1MPa) and in vacuum (0.005MPa). The anodizing current and nanotube length in vacuum are larger than those under atmospheric pressure, which cannot be explained by field-assisted dissolution theory. According to the oxygen bubble mould and Nernst equation, we attribute the higher current in vacuum to the faster gas evolution and oxide growth under narrower electrochemical potential gaps. By mathematically separating the total current into ionic and electronic parts, the faster oxide growth is further confirmed. The different nanotube lengths are due to various electric charge transported during anodization.

Origin of electronic properties of α-Hg3S2Cl2 polymorph

To investigate the energy bands structure of α-Hg 3 S 2 Cl 2 , first-principles calculations were performed within the density functional theory formalism using the SIESTA software package. Using the local density approximation the atomic positions are relaxed so as to minimize the forces acting on the atoms. The analysis of band energy dispersion shows that the VBM and CBM are located at Г symmetry point, resulting in a direct energy band gap of 3.198 eV. It is established that the nature of interatomic interactions has complex character and includes covalent and ionic parts. The inclusion of spin-orbit coupling not strongly modifies the structure of energy bands.

Shock compressibility of iron calculated in the framework of quantum-statistical models with different ionic parts

Quantum-statistical calculations of shock compressibility of iron are performed. Electronic part of thermodynamic functions is calculated in the framework of three quantum-statistical approaches: the Thomas-Fermi, the Thomas-Fermi with quantum and exchange corrections and the Hartree-Fock-Slater models. The influence of ionic part of thermodynamic functions is taken into account separately with using three models: the ideal gas, the one-component plasma and the charged hard spheres models. The results of calculations are presented in the pressure range from 1 to 107 GPa for samples with initially densities 7.85, 4.31 and 2.27 g/cm3. Calculated Hugoniots are compared with available experimental data.

Density functional theory calculations on transition metal atoms adsorbed on graphene monolayers

Transition metal atom adsorption on graphene monolayers has been elucidated using periodic density functional theory under hybrid and generalized gradient approximation functionals. More specifically, we examined the adsorption of Cu, Fe, Zn, Ru, and Os on graphene monolayers by calculating, among others, the electronic density-of-states spectra of the adatom-graphene system and the overlap populations of the adatom with the nearest adsorbing graphene carbon atoms. These calculations reveal that Cu form primarily covalent bonds with graphene atoms via strong hybridization between the adatom orbitals and the sp band of the graphene substrate, whereas the interaction of the Ru and Os with graphene also contain ionic parts. Although the interaction of Fe with graphene atoms is mostly covalent, some charge transfer to graphene is also observed. The interaction of Zn with graphene is weak. Mulliken population analysis and charge contour maps are used to elucidate charge transfers between the adatom and the substrate. The adsorption strength is correlated with the metal adsorption energy and the height of the metal adatom from the graphene plane for the geometrically optimized adatom-graphene system. Our analysis shows that show that metal adsorption strength follows the adatom trend Ru≈Os>Fe>Cu>Zn, as verified by corresponding changes in the adsorption energies. The increased metal-carbon orbital overlap for the Ru relative to Os adatom is attributed to hybridization defects.

Synthesis and physicochemical properties of a solid oxide nanocomposite based on a ZrO2–Y2O3–Gd2O3–MgO system

A highly dispersive powder with a (ZrO2)0.92(Y2O3)0.03(Gd2O3)0.03(MgO)0.02 composition and specific surface area of 150 m2/g has been synthesized via a method of coprecipitation of hydroxides with the subsequent cryochemical treatment of the gel. Nanoceramics based on the cubic modification of zirconium dioxide with the grain size of ~40–45 nm have been obtained. The temperature dependence of the specific electrical conductance of the nanoceramics within a temperature range of 350–870°C in air has been studied, and the ratio of the ionic and electronic parts of the conductance has been determined. Recommendations for the use of the obtained oxide nanocomposite as an electrolyte for a high-temperature fuel cell have been given.