Search

Over the past 130 years, Fischer-Speier esterification has been established as the benchmark method for synthesizing esters from organic acids and alcohols. The reaction's versatility, arising from the vast combinations of starting materials and the numerous catalytic alternatives to the traditional H2SO4, has maintained its relevance, with a steady flow of publications addressing new developments. This review highlights the most significant contributions to Fischer-Speier esterification over the past five years, with a particular emphasis on mechanistic advancements and innovative catalytic systems. Both homogeneous and heterogeneous catalytic approaches are discussed, including novel catalysts leveraging hydrogen-bonding interactions and systems offering fresh insights into specific reaction mechanisms and atypical methodologies. Some of these catalytic systems, as ionic liquids or sulfonated heterogeneous catalytic precursors, reached excellent yields (>90%), e.g., in the synthesis of fatty acids methyl esters. Also, classic catalysts such as H2SO4 and para-toluen sulfonic acid were optimized for quantitative conversions (e.g., in the esterification of trans-cinnamic acid with methanol). A consistent number of catalysts was studied with model substrates (as benzoic acid in combination with methanol, ethanol, and ethylene glycol), and new activation pathways were presented. [ABSTRACT FROM AUTHOR]

The fast-growing area of battery technology requires the availability of highly stable, energy-efficient batteries for everyday applications. This, in turn, calls for research into new battery materials, especially with regard to a battery's main component: the electrolytes. Besides the demands associated with solid ionic conduction and appropriate electrochemical behaviour, considerable effort will be necessary to thoroughly reduce safety risks in terms of flammability, leakage, and thermal runaway. Consequently, completely new classes of electrolytes need to be developed that are compatible with energy storage systems. Despite the progress made in solid polymer electrolytes, such materials have suffered from limitations to their real-world application. Now, ionic liquids are considered a class of electrolytes with the most potential for the creation of more advanced and safer lithium–ion batteries. In recent decades, ILs have been widely explored as potential electrolytes in the search for new breakthroughs in the ESS field, such those associated with fuel cells, lithium–ion batteries, and supercapacitors. The present review will discuss ILs that present high ionic conductivity, a lower melting point below 100 °C, and which feature up to 5–6 V wide electrochemical potential windows vs. Li+/Li. Furthermore, ILs exhibit good thermal stability, non-flammability, and low volatility—all of which are attributes realized by appropriate cation–anion combinations. This paper seeks to review the status of research concerning ILs, along with the advantages and challenges yet to be overcome in their development. [ABSTRACT FROM AUTHOR]

We report the synthesis and characterization of a novel asymmetric imidazolium-based ionic liquid crystal (ILC) dimer exhibiting stable smectic phases over a wide temperature range, including room temperature. This unique molecular structure, combining two distinct mesogenic cores, reduces packing density, which enhances ion mobility and achieves high ionic conductivity in the smectic phase (0.1 mS cm−1 at 40 °C). Electrochemical impedance spectroscopy (EIS) confirmed improved ionic conductivity at lower temperatures, along with a stable electrochemical window of ±3 V. Application as a solid-state electrolyte in an electrochromic device demonstrated effective switching behavior and reversible redox cycles. These findings suggest that this asymmetric imidazolium-based ILC is a viable candidate for advanced electrochemical applications due to its structural stability and anisotropic ionic pathways. [ABSTRACT FROM AUTHOR]

In this paper, we focus on surface electrostatic potentials and a variety of statistically derived quantities defined in terms of the surface potentials. These have been shown earlier to be meaningful in describing features of these potentials and have been utilized to understand the interactive tendencies of molecules in condensed phases. Our current emphasis is on ionic salts and liquids instead of neutral molecules. Earlier work on ionic salts has been reviewed. Presently, our results are for a variety of singly charged cations and anions that can combine to form ionic solids or liquids. Our approach is computational, using the density functional B3PW91/6-31G(d,p) procedure for all calculations. We find consistently that the average positive and negative surface electrostatic potentials of the cations and anions decrease with the size of the ion, as has been noted earlier. A model using computed statistical quantities has allowed us to put the melting points of both ionic solids and liquids together, covering a range from 993 °C to 11 °C. [ABSTRACT FROM AUTHOR]

Regulating the nucleation temperature and growth rates during inverse temperature crystallization (ITC) is vital for obtaining high-quality perovskite single crystals via this technique. Precise control over these parameters enables growing crystals optimized for various optoelectronic devices. In this study, it is demonstrated that incorporating a 1-butyl-3-methylimidazolium bromide (BMIB) ionic liquid into the precursor solution of cesium lead bromide (CsPbBr3) brings about a dual enhancement effect. This includes a reduction in nucleation temperature from 85 °C to 65 °C and a significant improvement in both optoelectronic characteristics and crystal properties. The CsPbBr3 single crystals grown using ITC with BMIB added (method (2)) demonstrate improved chemical and physical properties (crystallinity, lattice strain, nonradioactive recombination, and trap density) compared to CsPbBr3 single crystals produced through conventional 85 °C ITC alone (method (1)). The exceptional quality of CsPbBr3 single crystals produced with the inclusion of BMIB allowed for the development of a highly responsive optoelectronic device, demonstrating heightened sensitivity to green light. The findings of this investigation reveal that the growth of perovskite single crystals assisted by ionic liquid exerts a substantial impact on the characteristics of the crystals. This influence proves advantageous for the development of optoelectronic devices based on single crystals. [ABSTRACT FROM AUTHOR]

In this work, we describe the phase behaviour and the dielectric and conductivity response of new light-responsive ionic liquid crystals, ILCs, which can be applied as controllable electrolytes. The materials include two different dicationic viologens, the asymmetric 6BP18 and the symmetric EV2ON(Tf)2, containing bistriflimide as the counterions, mixed with 5% and 50% molar, respectively, of one new photoresponsive mesogen called CNAzO14. These mixtures exhibit liquid crystal behaviour, light responsiveness through the E-Z photoisomerisation of the azobenzene groups in CNAzO14, and strong dielectric responses. The 5%-CNAzO14/Ev2ON(Tf)2 mixture displays direct current conductivities in the 10−7 S·cm−1 range, which can be increased by a two-fold factor upon the irradiation of UV light at 365 nm. Our findings set the grounds for designing new smart ionic soft materials with nanostructures that can be tuned and used for energy conversion and storage applications. [ABSTRACT FROM AUTHOR]

Ionic liquid crystals (ILCs), a class of soft matter materials whose properties can be tuned by the wise pairing of the cation and anion, have recently emerged as promising candidates for different applications, combining the characteristics of ionic liquids and liquid crystals. Among those potential uses, this review aims to cover chromogenic ILCs. In this context, examples of photo-, electro- and thermochromism based on ILCs are provided. Furthermore, thermotropic and lyotropic ionic liquid crystals are also summarised, including the most common chemical and phase structures, as well as the advantages of confining these materials. This manuscript also comprises the following main experimental techniques used to characterise ILCs: Differential Scanning Calorimetry (DSC), Polarised Optical Microscopy (POM) and X-Ray Powder Diffraction (XRD). Chromogenic ILCs can be interesting smart materials for energy and health purposes. [ABSTRACT FROM AUTHOR]

This study examines the potential of fungal chitosan derived from Aspergillus niger as a sustainable alternative to traditional petrochemical-based ingredients in cosmetic products. Specifically, the research examines the solubility of fungal chitosan in aqueous solutions of varying ionic strength and its adsorption onto negatively charged surfaces that mimic human hair keratin. The adsorption behavior, water content, and frictional properties of chitosan films were evaluated using a quartz crystal microbalance with dissipation monitoring and a surface force apparatus (SFA). The findings indicated that fungal chitosan exhibits good solubility at a pH of 4.5. Conversely, the adsorption of chitosan is subject to the influence of both polymer concentration and ionic strength. At the lowest ionic strengths, a screening-enhanced adsorption process occurs as a consequence of the reduction in chitosan solubility in the presence of salt. This results in the depletion of polymer chains from the solution and their subsequent deposition. An increase in ionic strength above 15–20 mM results in a worsening of the chitosan–surface interaction, due to the simultaneous screening of both the chitosan and the surface charges. This results in a hindrance to the adsorption process. The deposited films are highly hydrated, and this hydration increases with both polymer concentration and ionic strength. Furthermore, the films exhibit a predominantly elastic behavior, and the response of the films under shear deformations shows a strong dependence on the polymer concentration. These findings contribute to the development of environmentally friendly cosmetic formulations that meet consumer demands for sustainability. [ABSTRACT FROM AUTHOR]

The increasing demand for safe and high-energy-density battery systems has led to intense research into solid electrolytes for rechargeable batteries. One of these solid electrolytes is the NASICON-type Li1+xAlxTi2−x(PO4)3 (LATP) material. In this study, different boron compounds (10% B2O3 doped, 10% H3BO3 doped, and 5% B2O3 + 5% H3BO3 doped) were doped at total 10 wt.% into the Ti4+ sites of an LATP solid electrolyte to investigate the structural properties and ionic conductivity of solid electrolytes using the solid-state synthesis method. Characterization of the synthesized samples was conducted using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). The XRD patterns of the boron-doped LATP (LABTP) samples show that the samples have a rhombohedral phase with space group R 3 ¯ c together and low amounts of impurity phases. While all the LABTP samples exhibited similar ionic conductivity values of around 10−4 S cm−1, the LABTP2 sample doped with 10 wt.% H3BO3 demonstrated the highest ionic conductivity. These findings suggest that varying B3+ ion doping strategies in LATP can significantly advance the development of solid electrolytes for all-solid-state lithium-ion batteries. [ABSTRACT FROM AUTHOR]

This study investigates the radiative relaxation of electronic excitations through luminescence spectroscopy techniques applied to high-purity KBr crystals subjected to low-temperature (85 K) uniaxial deformation along the <100> and <110> crystallographic directions. Results demonstrate that the most significant enhancement in the intensity of σ-(4.42 eV) and π-(2.3 eV) luminescence from self-trapped excitons in KBr crystals occurs with elastic deformation along the <110> direction, aligning with the axis of the hole component of the anion self-trapped exciton. Deformation-induced changes in X-ray, tunneling, and thermally stimulated luminescence spectra reveal a new band, denoted as Ex, peaking at approximately 3.58 eV, attributed to tunneling charge exchange between the F'- and VK-centers in their ground state. [ABSTRACT FROM AUTHOR]

Although perovskite has great potential in optoelectronic devices, the simultaneous satisfaction of material stability and high performance is still an issue that needs to be solved. Most perovskite optoelectronic devices use quantum dot spin coating or the gas-phase growth of perovskite thin films as the photoelectric conversion layer. Due to stability limitations, these materials often experience a significant decrease in photoelectric conversion efficiency when encountering liquid reagents. The self-assembled growth of hybrid perovskite crystals determines superior lattice ordering and stability. There are three types of ionic liquids—[Emim]BF4, EMIMNTF2, and HMITFSI—that can effectively enhance the X-ray photoelectric conversion performance of hybrid perovskite crystal CH3NH3PbI3 (MAPbI3), and the enhancement in the photocurrent leads to an improvement in the sensitivity of X-ray detectors. We soak the perovskite crystals in an ionic liquid and perform two treatment methods: electrification and dilution with ETOH solution. It is interesting to find that MAPbI3 perovskite single crystal materials choose the same optimized ionic liquid species in X-ray detection and photovoltaic power generation applications, and the effect is quite the opposite. Compared with untreated MAPbI3 crystals, the average photocurrent density of Electrify-HMITFSI MAPbI3 increased by 826.85% under X-ray excitation and the sensitivity of X-ray detectors made from these treated MAPbI3 crystals significantly increased by 72.6%, but the intensity of the PL spectrum decreased to 90% of the untreated intensity. [ABSTRACT FROM AUTHOR]

External electric fields are an effective tool to induce phase transformations. The crystallization of ionic crystals from solution is a common phase transformation. However, understanding of mechanisms is poor at the molecular level. In this work, we carried out an experimental and theoretical investigation of the external electric-field-induced crystallization of TKX-50 from saturated formic acid solution by finite-temperature string (FTS) with order parameters (OPs) as collective variables for ionic crystals. The minimum-free-energy path was sketched by the string method in collective variables. The results show that the K-means clustering algorithm based on Euclidean distance and density weights can be used for enhanced sampling of the OPs in external electric-field-induced crystallization of ionic crystal from solution, which improves the conventional FTS. The crystallization from solution is a process of surface-mediated nucleation. The external electric field can accelerate the evolution of the string and decrease the difference in the potential of mean forces between the crystal and the transition state. Due to the significant change in OPs induced by the external electric field in nucleation, the crystalline quality was enhanced, which explains the experimental results that the external electric field enhanced the density, detonation velocity, and detonation pressure of TKX-50. This work provides an effective way to explore the crystallization of ionic crystals from solution at the molecular level, and it is useful for improving the properties of ionic crystal explosives by using external electric fields. [ABSTRACT FROM AUTHOR]

The study of new catalytic protocols for the synthesis of organic compounds with a more sustainable perspective is of interest. The use of ionic organic solids, such as 1,3-bis(carboxymethyl)imidazolium chloride as a catalyst has allowed the Michael addition of N-heterocycles to chalcones. This methodology has been applied to the unique preparation of the potential bioactive compound 1-(3,4-dimethoxyphenyl)-3-(4-methoxyphenyl)-3-(1H-1,2,4-triazol-1-yl)propan-1-one with moderate yield, due to the retro-Michael reaction. Both synthetic reactions (i.e., preparation of chalcone and triazole Michael-addition to chalcone) have good green metrics. [ABSTRACT FROM AUTHOR]

The mineral CaF2 is the archetype of the α fluorite structure and its high-pressure phase transition to γ cotunnite is an ideal test bed for exploring the effects of kinetics. The inter-disciplinary topic of the kinetics of dynamically driven phase transitions is at the forefront of condensed matter physics, both for its theoretical importance and its relevance to technological applications at extreme conditions of pressure and temperature. Here we probe the α → γ → α structural transformations taking place over the nanosecond timescale of a dynamic event, beginning-to-end: from the principal shock Hugoniot state, followed by a quasi-steady off-Hugoniot release state, and finally the unsteady return to near-ambient conditions. We present quantitative, atomic-scale data of the unfolding of the dynamically driven phase transition and its subsequent reversal close to the α/γ phase boundary. Dynamic loading with a two-stage gas gun is coupled with in situ time-resolved synchrotron X-ray diffraction and with continuum scale velocimetry at the Dynamic Compression Sector (DCS), Advanced Photon Source, Argonne National Laboratory. Our results demonstrate the time dependence of phase transitions and highlight the need for modeling of transition kinetics in dynamically driven processes. [ABSTRACT FROM AUTHOR]

Two neutral copper(I) halide complexes ([Cu(BTU)2X], X = Cl, Br) were prepared by the reduction of the corresponding copper(II) halides (chloride or bromide) with a benzoylthiourea (BTU, N-(3,4-diheptyloxybenzoyl)-N′-(4-heptadecafluorooctylphenyl)thiourea) ligand in ethanol. The two copper(I) complexes show a very interesting combination of 2D supramolecular structures, liquid crystalline, emission, and 1D ionic conduction properties. Their chemical structure was ascribed based on ESI–MS, elemental analysis, IR, and NMR spectroscopies (1H and 13C), while the mesomorphic behavior was analyzed through a combination of differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and powder X-ray diffraction (XRD). These new copper(I) complexes have mesomorphic properties and exhibit a hexagonal columnar mesophase over a large temperature range, more than 100 K, as evidenced by DSC studies and POM observations. The thermogravimetric analysis (TG) indicated a very good thermal stability of these samples up to the isotropization temperatures and over the whole temperature range of the liquid crystalline phase existence. Both complexes displayed a solid-state emission with quantum yields up to 8% at ambient temperature. The electrical properties of the new metallomesogens were investigated by variable temperature dielectric spectroscopy over the entire temperature range of the liquid crystalline phase. It was found that the liquid crystal phases favoured anhydrous proton conduction provided by the hydrogen-bonding networks formed by the NH...X moieties (X = halide or oxygen) of the benzoylthiourea ligand in the copper(I) complexes. A proton conductivity of 2.97 × 10−7 S·cm−1 was achieved at 430 K for the chloro-complex and 1.37 × 10−6 S·cm−1 at 440K for the related bromo-complex. [ABSTRACT FROM AUTHOR]

The present work reports on the synthesis, structural, spectroscopic, and theoretical studies of a new solid state ionic compound mainly composed of tris(1,10-phenanthroline)zinc(II) cations and N,N′,N″-tris(carboxymethyl)-1,3,5-benzenetricarboxamide anions. Colorless and well-shaped crystals were obtained from an alkaline aqueous methanolic solution, and single-crystal X-ray diffraction revealed a distinct supramolecular network. Powder diffraction techniques and Rietveld analysis confirmed the phase purity of the crystalline probes. The compound crystallizes in the orthorhombic space group Pbca with a cell volume of 9517.0 Å3. The complex cations [Zn(phen)3]2+ are interconnected via π–π-interactions and form a cationic layer network with holes. The organic counterion, as a dianion, forms dimeric units through π–π-interactions and hydrogen bonds, which also form an anionic layer network with honeycomb-like holes through cooperative classical hydrogen bonds of the O∙∙∙H–O and O∙∙∙H–N type with attractive secondary electrostatic interactions. Using the holes, the resulting supramolecular framework can be described as an interpenetrated network of separate anionic and cationic layers linked by further weaker non-covalent interactions such as C–H∙∙∙π and lone-pair∙∙∙π interactions. DFT calculations confirmed the experimentally observed spectroscopic (IR and Raman) findings. For a deeper insight into the structural arrangement in the crystal, the different Hirshfeld surfaces of the cation and anion, the pairwise interaction energies as well as the energy framework were calculated, supporting the dominance of attractive and repulsive electrostatic forces between the ions. [ABSTRACT FROM AUTHOR]

The 1,3-bis(sulfomethyl)imidazole (bsmim) was effectively prepared by a multicomponent reaction, employing aminomethanesulfonic acid, glyoxal, and formaldehyde. The catalytic activity of bsmim was tested in the synthesis of quinoline derivatives, by means of the Friedländer reaction, and in the allylic substitution of alcohols with nitrogen-containing heterocycles. The performance of sulfo-imidazole derivative (bsmim) resulted in higher comparison with the carboxyimidazole analogs (bcmim and bcmimCl), under the same reaction conditions. This type of ionic organic solid allows the promotion of reactions in the absence of solvent and mild reaction conditions, which improves the sustainability of organic synthetic processes. [ABSTRACT FROM AUTHOR]

In metal halide perovskites, charge transport in the bulk of the films is influenced by trapping and release and nonradiative recombination at ionic and crystal defects. Thus, mitigating the formation of defects during the synthesis process of perovskites from precursors is required for better device performance. An in-depth understanding of the nucleation and growth mechanisms of perovskite layers is crucial for the successful solution processing of organic–inorganic perovskite thin films for optoelectronic applications. In particular, heterogeneous nucleation, which occurs at the interface, must be understood in detail, as it has an effect on the bulk properties of perovskites. This review presents a detailed discussion on the controlled nucleation and growth kinetics of interfacial perovskite crystal growth. Heterogeneous nucleation kinetics can be controlled by modifying the perovskite solution and the interfacial properties of perovskites adjacent to the underlaying layer and to the air interface. As factors influencing the nucleation kinetics, the effects of surface energy, interfacial engineering, polymer additives, solution concentration, antisolvents, and temperature are discussed. The importance of the nucleation and crystal growth of single-crystal, nanocrystal, and quasi-two-dimensional perovskites is also discussed with respect to the crystallographic orientation. [ABSTRACT FROM AUTHOR]

The synthesis and thermotropic behaviour of some di-alkyloxy-phenyl-1,2,4-triazolium trifluoromethane-sulfonate salts bearing a seven-carbon atom perfluoroalkyl chain on the cation is herein described. The fluorinated salts presenting a 1,2,4-triazole as a core and differing in the length of two alkyloxy chains on the phenyl ring demonstrated a typical liquid crystalline behaviour. The mesomorphic properties of this set of salts were studied by differential scanning calorimetry and polarized optical microscopy. The thermotropic properties are discussed on the grounds of the tuneable structures of the salts. The results showed the existence of a monotropic, columnar, liquid crystalline phase for the salts tested. An increase in the temperature mesophase range and the presence of two enantiotropic mesophases for the sixteen-atom alkyloxy chain salt can be observed by increasing the length of the alkyloxy chain on the phenyl ring. [ABSTRACT FROM AUTHOR]

Crystal engineering of multi-component molecular crystals, cocrystals, is a subject of growing interest, thanks in part to the potential utility of pharmaceutical cocrystals as drug substances with improved properties. Whereas molecular cocrystals (MCCs) are quite well studied from a design perspective, ionic cocrystals (ICCs) remain relatively underexplored despite there being several recently FDA-approved drug products based upon ICCs. Successful cocrystal design strategies typically depend on strong and directional noncovalent interactions between coformers, as exemplified by hydrogen bonds. Understanding of the hierarchy of such interactions is key to successful outcomes in cocrystal design. We herein address the crystal engineering of ICCs comprising azole functional groups, particularly imidazoles and triazoles, which are commonly encountered in biologically active molecules. Specifically, azoles were studied for their propensity to serve as coformers with strong organic (trifluoroacetic acid and p-toluenesulfonic acid) and inorganic (hydrochloric acid, hydrobromic acid and nitric acid) acids to gain insight into the hierarchy of NH+···N (azolium-azole) supramolecular heterosynthons. Accordingly, we combined data mining of the Cambridge Structural Database (CSD) with the structural characterization of 16 new ICCs (11 imidazoles, 4 triazoles, one imidazole-triazole). Analysis of the new ICCs and 66 relevant hits archived in the CSD revealed that supramolecular synthons between identical azole rings (A+B−A) are much more commonly encountered, 71, than supramolecular synthons between different azole rings (A+B−C), 11. The average NH+···N distance found in the new ICCs reported herein is 2.697(3) Å and binding energy calculations suggested that hydrogen bond strengths range from 31–46 kJ mol−1. The azolium-triazole ICC (A+B−C) was obtained via mechanochemistry and differed from the other ICCs studied as there was no NH+···N hydrogen bonding. That the CNC angles in imidazoles and 1,2,4-triazoles are sensitive to protonation, the cationic forms having larger (approximately 4.4 degrees) values than comparable neutral rings, was used as a parameter to distinguish between protonated and neutral azole rings. Our results indicate that ICCs based upon azolium-azole supramolecular heterosynthons are viable targets, which has implications for the development of new azole drug substances with improved properties. [ABSTRACT FROM AUTHOR]

The triprotic ammonium carboxylate ionic liquid crystal (2-hydroxyethyl)ammonium oleate (MO) has been studied as a neat lubricant and as a lubricant additive in two base oils, PAO6 and 100N. The lubricants have been used in commercially pure copper-OFHC copper balls on disk reciprocating sliding contact at room temperature. Neat MO presents a very good lubricating performance, with a friction coefficient of 0.06 and a wear rate of OFHC copper disk of 4.15 × 10−7 mm3/N·m. These results are, respectively, 94% and 98% lower than those obtained for PAO6, with similar reductions obtained with respect to 100N. MO has also been studied as an additive in 2wt.% proportion. The severe abrasive wear mechanism that takes place in the presence of neat base oils is reduced by the MO additive. [ABSTRACT FROM AUTHOR]

We designed an ionic salt by combining a π-conjugated anion and a cholinium cation. It formed homogeneous mixtures with water in various weight ratios. The obtained mixtures showed chromonic liquid-crystalline behavior in a wider concentration range as compared to analogous compounds with inorganic cations. Although only an exhibition of nematic phases was previously reported by Kasianova et al. for analogous compounds with an inorganic cation in 2010, the ionic salt with a cholinium cation showed not only nematic phases but also hexagonal columnar phases. The formation of hexagonal columnar phases is attributed to its ability to form mesophases even in a high concentration range, which enables the cylindrical aggregates of the π-conjugated anions to form dense packing. By examining the states of the water molecules, we revealed that the ability of the cholinium cation to form a hydrated ionic liquid state strongly contributes to the widening of the concentration range forming chromonic liquid-crystalline behavior. [ABSTRACT FROM AUTHOR]

Matrix selection is a critical factor for success in glycomics studies using matrix-assisted laser desorption/ionization–mass spectrometry (MALDI–MS). In this study, we evaluated and optimized a new solid ionic matrix—O-benzylhydroxylamine (BOA)/2,5-dihydroxybenzoic acid (DHB)/Na—containing BOA and a small amount of sodium as the counter salt of DHB. The concentration of a mixture of BOA/DHB/Na and glycans on a MALDI target plate led to O-benzyloxy tagging of the reducing ends of the glycans. The BOA/DHB/Na matrix showed excellent aggregation performance and the ability to form a homogeneous solid salt on the MALDI target plate with a water-repellent surface. In addition, the BOA/DHB/Na matrix showed a simple peak pattern with suppressed in-source and post-source decay of the reducing ends of the glycans, as well as improved ionization efficiency of glycans. Utilizing the characteristics of the BOA/DHB/Na matrix, O-glycan analysis of porcine stomach mucin showed excellent detection sensitivity and reproducibility of the peak patterns. This BOA/DHB/Na matrix can accelerate glycomics studies using MALDI–MS and, in combination with other organic salt-type matrices that we have developed, constitutes a valuable tool for glycomics studies. [ABSTRACT FROM AUTHOR]

The main purpose of the present study is to improve the tribological performance of aqueous lubricants with the use of ecofriendly, fatty acid-derived additives. The protic ionic liquid crystal bis(2-hydroxyethyl)ammonium stearate (DES) has been added to 50:50 water+ethylene glycol (W–EG) to obtain (W–EG)+0.5%DES; (W–EG)+1%DES and (W–EG)+2%DES emulsions. The new lubricants have been studied in sapphire-AISI (American Iron and Steel Institute) 316L stainless-steel pin-on-disk sliding contacts. The addition of DES reduces the friction coefficient by up to 76% and wear rate by up to 80%, with respect to (W–EG). The best performance is found for the emulsions with the lower proportion of DES (0.5 and 1 wt.%). These results have been related to viscosity and turbidity values. Wear mechanisms have been studied by Scanning Electron Microscopy/Energy Dispersive X-ray Spectroscopy (SEM/EDX) and by Raman microscopy. While W–EG shows a severe abrasive mechanism, no abrasion marks are present inside the wear track after lubrication with (W–EG)+0.5%DES, the emulsion with the lowest wear rate. After lubrication with W–EG, an increase in oxygen content is observed inside the wear track, as determined by EDX and confirmed by Raman microscopy, which shows the presence of iron oxides. The addition of DES reduces these oxidation processes. [ABSTRACT FROM AUTHOR]

Supported ionic liquid phases offer several advantages related with catalysis. Immobilization of ionic liquid on the solid support provides catalytic activity or efficient matrix for active phases, as enzymes or metal compounds. Ionic liquid can be physically adsorbed on the carrier (supported ionic liquid phase) or chemically grafted to the material surface (supported ionic liquid-like phase). The use of supported ionic liquid phases improves mass transport, reduces ionic amount in the process and, most importantly, enables effortless catalyst separation and recycling. Moreover, chemical modification of the surface material with ionic liquid prevents its leaching, enhancing length of catalyst life. Silica-based materials have become an effective and powerful matrix for supported ionic liquid-like phase due to its cost-efficiency, presence of hydroxyl groups on the surface enabling its functionalization, and specific material properties, such as the size and shapes of the pores. For these reasons, supported ionic liquid-like phase silica-based materials are successfully used in the organic catalysis. [ABSTRACT FROM AUTHOR]

Featured Application: Advancements in energy storage technology, especially in the areas of safety and energy density, are vital for continued sustainable improvements in electrified transportation and power distribution. Organic ionic crystals and ionic liquid crystals are promising materials for use as electrolytes in safer, solvent-free rechargeable lithium-ion batteries. In this study, the amphiphilic salt lithium trifluoromethanesulfonylimide octadecane (C18LiTFSI) was used as a basis to investigate the effects of anion density and cation coordination sites within blended electrolytes with strong ionic aggregation. C18LiTFSI was previously reported as a single-component, ion-condensed electrolyte with a wide layered liquid crystalline phase regime. Three additive molecules with varyingly sized polar sulfonyl groups attached to an octodecane-tail were synthesized and mixed with C18LiTFSI. The thermal properties, morphology, and ionic conductivity of the blended electrolytes were characterized. It was found that the blended electrolytes exhibited layered liquid crystalline morphology over a narrower temperature range than the pure salt, and the ionic conductivity of the blended liquid crystalline electrolytes were generally lower than that of the pure salt. Surprising, the additives were found to have the greatest effect on the bulk ionic conductivity of the semicrystalline phase of the electrolytes. Addition of minor fractions of methylsulfonyloctadecane to C18LiTFSI resulted in increases in conductivity of over two orders of magnitude at room temperature, while addition of ethylsulfonyloctadecane or isopropylsulfonyloctadecane with the larger head group resulted in decreased ionic conductivity over the entire composition space and temperature range investigated. [ABSTRACT FROM AUTHOR]

Materials with pyrochlore structure A2B2O7 have attracted considerable attention owing to their various applications as catalysts, sensors, electrolytes, electrodes, and magnets due to the unique crystal structure and thermal stability. At the same time, the possibility of using such materials for electrochemical applications in salt melts has not been studied. This paper presents the new results of obtaining high-density Mg2+-doped ceramics based on Gd2Zr2O7 with pyrochlore structure and comprehensive investigation of the electrical properties and chemical stability in a lithium chloride melt with additives of various concentrations of lithium oxide, performed for the first time. The solid solution of Gd2−xMgxZr2O7−x/2 (0 ≤ x ≤ 0.10) with the pyrochlore structure was obtained by mechanically milling stoichiometric mixtures of the corresponding oxides, followed by annealing at 1500 °C. The lattice parameter changed non-linearly as a result of different mechanisms of Mg2+ incorporation into the Gd2Zr2O7 structure. At low dopant concentrations (x ≤ 0.03) some interstitial positions can be substituted by Mg2+, with further increasing Mg2+-content, the decrease in the lattice parameter occurred due to the substitution of host-ion sites with smaller dopant-ion. High-density ceramics 99% was prepared at T = 1500 °C. According to the results of the measurements of electrical conductivity as a function of oxygen partial pressure, all investigated samples were characterized by the dominant ionic type of conductivity over a wide range of pO2 (1 × 10–18 ≤ pO2 ≤ 0.21 atm) and T < 800 °C. The sample with the composition of x = 0.03 had the highest oxygen-ion conductivity (10−3 S·cm−1 at 600 °C). The investigation of chemical stability of ceramics in the melt of LiCl with 2.5 mas.% Li2O showed that the sample did not react with the melt during the exposed time of one week at the temperature of 650 °C. This result makes it possible to use these materials as oxygen activity sensors in halide melts. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of novel ionic liquid crystals based on pyridinium salts with Br− and PF6− counterions are described in this work. These pyridinium salts were derived from 4-hydroxypyridine, both by N- and O-alkylation. The 3,4,5-tri(alkyloxy)-benzyl mesogenic unit was attached to the nitrogen atom of the pyridinium ring. Alkyl chains with a different number of carbon atoms (6, 8, 10, 12 and 14) were employed in order to show the effect on the stability of mesophase. The POM (polarizing optical microscopy) and XRD (powder X-ray diffraction) studies indicated that bromide salts with shorter chains C6, C8 and C10 do not show mesomorphic properties, while longer chain analogues with C12 and C14 exhibit two enantiotropic columnar phases. Surprisingly, the pyridinium salts with the larger size PF6− counterion do not exhibit liquid crystal properties. [ABSTRACT FROM AUTHOR]

A protonic ceramic fuel cell (PCFC) has great potential for medium temperature power generation. Its working process, however, is complicated and quite different from the traditional oxygen ionic solid oxide fuel cell (O2−-SOFC) and proton exchange membrane fuel cell (PEMFC). In this paper, a multi-physical model for the PCFC with H+/e−/O2− mixed conducting cathode is established, in which the fuel- and oxidant-diffusing processes; electron-, oxygen ion-, and proton-conducting processes; three electrochemical reactions; and their coupling working details are carefully considered. Taking Ni-BZCY/BZCY/BZCY-LSCF PCFC as an example, the validation of the model is well verified by good agreements with the experiment iop-Vop curves at different temperatures. The result shows that the cathodic electrochemical reactions will be concentrated to a small thickness near the electrolyte because of the greatly decreased ionic conductivity compared with the high electronic conductivity at an intermediate temperature. O2− within the PCFC cathode is only an intermediate transform substance between the electrons and protons. Thus, there is a peak oxygen ion current distribution within the composite cathode of PCFC. The cathodic oxygen reduction half reaction is found to be a key factor to dominate the total PCFC voltage loss at the intermediate temperature zone. The concentration polarization of anode-supported PCFC is small, due to the vapors that are generated in the cathode side instead of anode side. [ABSTRACT FROM AUTHOR]

In this paper, we report the synthesis and characterization of unconventional nanocomposites made of bimetallic nanoparticles dispersed in a liquid crystal glass. Core-shell bimetallic nanoparticles (Ag/Au or Au/Ag) and Ag-Au bimetallic nanoalloys are synthesized using cadmium alkanoate glass-forming liquid crystals as nanoreactors. Optical spectra of the produced glassy nanocomposites exhibit a distinctive absorption peak due to a surface plasmon resonance. In addition, these unusual materials demonstrate a strong nonlinear–optical response probed by means of the Z-scan technique. The use of near-infrared (1064 nm) and visible (532 nm) nanosecond laser pulses reveal a variety of nonlinear–optical mechanisms that depend on the composition of the studied nanocomposites. Our results indicate that metal alkanoate-based glass-forming ionic liquid crystals with embedded plasmonic nanoparticles are promising, yet they are overlooked photonic nanomaterials suitable for optical and nonlinear-optical applications. [ABSTRACT FROM AUTHOR]

The phenomenon of total external reflection of X-rays at a sliding angle of incidence of a beam of incident X-rays is investigated. For metals, a quantitative law of direct dependence of the refractive index decrement on the interplane distance is obtained. The excitation of surface plasmons by X-rays that have experienced complete external reflection is detected. For surface plasmons, a dimensional effect was observed, expressed in an increase in the energy of plasmons and the concentration of conduction electrons with an increase in the depth of the output of surface plasmons. By the method of dispersion of surface plasmons, internal mechanical micro-stresses and spontaneous polarization of the surface layers of glassy dielectrics and in thin layers of vanadium dioxide were determined. The absence of micro-stresses in the lithium fluoride ionic single crystal was found out, and the polarization observed in it is due to the large dipole moment of the molecules of this crystal. In thin films of vanadium dioxide, the dependence of micro-stresses on the stresses in the substrates was found. [ABSTRACT FROM AUTHOR]

A Brönsted acidic ionic solid pyridinium-functionalized organosilica network (PMO-Py-IL) was demonstrated to efficiently catalyse one-pot Biginelli condensation reaction. The green synthesis of 3,4-dihydro-2(H)-pyrimidinones (DHPMs) with high yield was carried out via one-pot three component condensation of β- dicarbonyls, aldehydes, and urea in the presence of a catalytic amount of PMO-Py-IL nanomaterial as an efficient nanocatalyst under solvent free conditions. Furthermore, the catalyst showed outstanding stability and could be easily separated and reused for at least ten reaction runs without significant loss of activity and product selectivity. The green protocol features simple set-up, cost-effectiveness, easy work-up, eco-friendly and mild reaction conditions. [ABSTRACT FROM AUTHOR]

Featured Application: Fluorinated ionic liquid crystals, due to their easy synthetic modulation, inertness, and potential as quasi solid-state electrolytes, can find perspective application in DSSCs solar cells, but also in many other electronic and optoelectronic devices, such as supercapacitors, smart windows, and lithium batteries. The synthesis and characterization of a new class of 1,2,4-oxadiazolylpyridinium as a cationic scaffold for fluorinated ionic liquid crystals is herein described. A series of 12 fluorinated heterocyclic salts based on a 1,2,4-oxadiazole moiety, connected through its C(5) or C(3) to an N-alkylpyridinium unit and a perfluoroheptyl chain, differing in the length of the alkyl chain and counterions, has been synthesized. As counterions iodide, bromide and bis(trifluoromethane)sulfonimide have been considered. The synthesis, structure, and liquid crystalline properties of these compounds are discussed on the basis of the tuned structural variables. The thermotropic properties of this series of salts have been investigated by differential scanning calorimetry and polarized optical microscopy. The results showed the existence of an enantiotropic mesomorphic smectic liquid crystalline phase for six bis(trifluoromethane)sulfonimide salts. [ABSTRACT FROM AUTHOR]

To satisfy the demands of wireless communication systems for tunable shielding materials, in this work, a graphene/ion gel/graphene sandwich structure is proposed, based on graphene and a solid ionic material ion gel. After modelling, preparing and testing, it was found that the structure could achieve more than 10 dB shielding effectiveness tuning in GHz and THz bands. Meanwhile, the adjusting speed of the structure was also studied, displaying effective dynamic tuning in the second order. Furthermore, the fabricated samples have the advantages of a low profile, easily conformable, and convenient processing, which are of great potential in emerging electronic devices. [ABSTRACT FROM AUTHOR]

Featured Application: All solid-state lithium batteries, all solid-state thin-film lithium batteries. All-solid-state batteries (SSBs) are one of the most fascinating next-generation energy storage systems that can provide improved energy density and safety for a wide range of applications from portable electronics to electric vehicles. The development of SSBs was accelerated by the discovery of new materials and the design of nanostructures. In particular, advances in the growth of thin-film battery materials facilitated the development of all solid-state thin-film batteries (SSTFBs)—expanding their applications to microelectronics such as flexible devices and implantable medical devices. However, critical challenges still remain, such as low ionic conductivity of solid electrolytes, interfacial instability and difficulty in controlling thin-film growth. In this review, we discuss the evolution of electrode and electrolyte materials for lithium-based batteries and their adoption in SSBs and SSTFBs. We highlight novel design strategies of bulk and thin-film materials to solve the issues in lithium-based batteries. We also focus on the important advances in thin-film electrodes, electrolytes and interfacial layers with the aim of providing insight into the future design of batteries. Furthermore, various thin-film fabrication techniques are also covered in this review. [ABSTRACT FROM AUTHOR]

The ZrO2(MgO)/CaAl2O4+CaAl4O7 bilayer structure used for sulfur sensor was fabricated by the laser powder cladding (LPC) method using the MgO partially stabilized zirconia (2.7 wt% MgO-PSZ) as the substrate and the CaAl2O4 + CaAl4O7 composites as the coating material. The microstructure, phase composition and ionic conductivity of this bilayer structure were investigated for better application in the sulfur determination. The results indicated that the structure of the coating was dense and well-distributed with a thickness of 100 μm. The ionic conductivity of the ZrO2(MgO)/CaAl2O4+CaAl4O7 bilayer structure was up to 2.06 × 10−3 S·cm−1 at 850 °C that met the required ionic conductivity of ionic conductor for solid electrolyte sulfur sensor. Furthermore, the sulfur sensor Mo|Cr+Cr2O3| ZrO2(MgO)| CaAl2O4+CaAl4O7|[S]Fe| Mo was assembled used this bilayer structure and tested in carbon-saturated liquid iron at 1773 K and 1823 K. The stability and reproducibility of the sulfur sensor were satisfactory and could be used for sulfur determination in the liquid iron. [ABSTRACT FROM AUTHOR]

We extend the SG4 generalized gradient approximation, developed for covalent and ionic solids with a nonlocal van der Waals functional. The resulting SG4-rVV10m functional is tested, considering two possible parameterizations, for various kinds of bulk solids including layered materials and molecular crystals as well as regular bulk materials. The results are compared to those of similar methods, PBE + rVV10L and rVV10. In most cases, SG4-rVV10m yields a quite good description of systems (from iono-covalent to hydrogen-bond and dispersion interactions), being competitive with PBE + rVV10L and rVV10 for dispersion-dominated systems and slightly superior for iono-covalent ones. Thus, it shows a promising applicability for solid-state applications. In a few cases, however, overbinding is observed. This is analysed in terms of gradient contributions to the functional. [ABSTRACT FROM AUTHOR]

The interaction between a dislocation and impurities has been investigated by measurements of yield stress and proof stress, micro-hardness tests, direct observations of dislocation, internal friction measurements, or stress relaxation tests so far. A large number of investigations has been carried out by the separation of the flow stress into effective and internal stresses on the basis of the temperature dependence of yield stress, the strain rate dependence of flow stress, and stress relaxation. Nevertheless, it is difficult to investigate the interaction between a dislocation and obstacles during plastic deformation by the mentioned methods. As for the original method which combines strain-rate cycling tests with the Blaha effect measurement, the original method is different from above-mentioned ones and would be possible to clear it up. The strain-rate cycling test during the Blaha effect measurement has successively provided the information on the dislocation motion breaking away from the strain fields around dopant ions with the help of thermal activation, and seems to separate the contributions arising from the interaction between dislocation and the point defects and those from dislocations themselves during plastic deformation of ionic crystals. Such information on dislocation motion in bulk material cannot be obtained by the widely known methods so far. Furthermore, the various deformation characteristics derived from the original method are sensitive to a change in the state of dopant ions in a specimen by heat treatment, e.g., the Gibbs free energy (G0) for overcoming of the strain field around the dopant by a dislocation at absolute zero becomes small for the annealed KCl:Sr2+ single crystal (G0 = 0.26 eV) in comparison with that for the quenched one (G0 = 0.39 eV). [ABSTRACT FROM AUTHOR]

The neutral-ionic phase transition in TTF-CA was investigated by steady-state and time-resolved infrared spectroscopy. We describe the growth of high-quality single crystals and their characterization. Extended theoretical calculations were performed in order to obtain the band structure, the molecular vibrational modes and the optical spectra along all crystallographic axes. The theoretical results are compared to polarization-dependent infrared reflection experiments. The temperature-dependent optical conductivity is discussed in detail. We study the photo-induced phase transition in the vicinity of thermally-induced neutral-ionic transition. The observed temporal dynamics of the photo-induced states is attributed to the random-walk of neutral-ionic domain walls. We simulate the random-walk annihilation process of domain walls on a one-dimensional chain. [ABSTRACT FROM AUTHOR]

In recent years, there has been extensive research and continuous development on second-order nonlinear optical (NLO) crystal materials due to their potential applications in telecommunications, THz imaging and spectroscopy, optical information processing, and optical data storage. Recent progress in second-order NLO ionic organic crystal materials is reviewed in this article. Research has shown that the second-order nonlinear optical properties of organic crystal materials are closely related to their molecular structures. The basic structures of ionic organic conjugated molecules with excellent nonlinear optical properties are summarized. The effects of molecular structure, for example, conjugated electron systems, electronic properties of donor-acceptor groups, and different counter-anion effects on second order NLO properties and crystal packing are studied. [ABSTRACT FROM AUTHOR]

The computed electrostatic potentials on C,H,N,O molecular solids and nitrogen-rich C,H,N,O salts are used in analyzing and comparing intralattice attractive forces and crystal densities in these two categories of compounds. Nitrogen-rich C,H,N,O salts are not an assured path to high densities. To increase the likelihood of high densities, small cations and large anions are suggested. Caution is recommended in predicting benefits of nitrogen-richness for explosive compounds. [ABSTRACT FROM AUTHOR]

The presence of ions in liquid crystals is one of the grand challenges that hinder the application of liquid crystals in various devices, which include advanced 3-D and flexible displays, tunable lenses, etc. Not only do they compromise the overall performance of liquid crystal devices, ions are also responsible for slow response, image sticking, and image flickering, as well as many other negative effects. Even highly purified liquid crystal materials can get contaminated during the manufacturing process. Moreover, liquid crystals can degrade over time and generate ions. All of these factors raise the bar for their quality control, and increase the manufacturing cost of liquid crystal products. A decade of dedicated research has paved the way to the solution of the issues mentioned above through merging liquid crystals and nanotechnology. Nano-objects (guests) that are embedded in the liquid crystals (hosts) can trap ions, which decreases the ion concentration and electrical conductivity, and improves the electro-optical response of the host. In this paper, we (i) review recently published works reporting the effects of nanoscale dopants on the electrical properties of liquid crystals; and (ii) identify the most promising inorganic and organic nanomaterials suitable to capture ions in liquid crystals. [ABSTRACT FROM AUTHOR]

The last five years' achievements in the synthesis and investigation of thermotropic ionic liquid crystals are reviewed. The present review describes the mesomorphic properties displayed by organic, as well as metal-containing ionic mesogens. In addition, a short overview on the ionic polymer and self-assembled liquid crystals is given. Potential and actual applications of ionic mesogens are also discussed. [ABSTRACT FROM AUTHOR]

This paper reports the synthesis of a series of new tetraethylammonium-based amino acid chiral ionic liquids (CILs). Their physico-chemical properties, including melting point, thermal stability, viscosity and ionic conductivity, have been comprehensively studied. The obtained results indicated that the decomposition for these salts proceeds in one step and the temperature of decomposition (Tonset) is in the range of 168-210 °C. Several new CILs prepared in this work showed high ionic conductivity compared to the amino acid ionic liquids (AAILs) found in the literature. [ABSTRACT FROM AUTHOR]

An overview of the chemical compounds forming the rare smectic T phases is presented with references to the historical context. Thermodynamics (transition temperatures, enthalpies) along with the factors (stereochemical constraints, electrostatic interactions, aliphatic chain stacking, intermolecular forces) contributing to the adoption of tetragonal scaffolds are also discussed. Characteristic optical microscopy textures and X-ray diffraction patterns are presented. In parallel, a comparison of the geometrical parameters such as distances between atoms, molecular areas, volumes, and lattice parameters with the closest two-dimensional and three-dimensional organizations, is performed. [ABSTRACT FROM AUTHOR]

Mixtures of nematic liquid crystals (LCs) with chiral ionic liquids (CILs) may find application as active materials for electrically driven broadband mirrors. Five nematic liquid crystal hosts were mixed with twenty three ionic liquids, including chiral ones, and studied in terms of their miscibility within the nematic phase. Phase diagrams of the mixtures with CILs which exhibited twisted nematic phase were determined. Miscibility, at levels between 2 and 5 wt%, was found in six mixtures with cyanobiphenyl-based liquid crystal host—E7. On the other hand, the highest changes in the isotropization temperature was found in the mixtures with isothiocyanate-based liquid crystal host—1825. Occurrence of chemical reactions was found. A novel chiral binaphtyl-based organic salt [N11116][BNDP] was synthesized and, in reaction to the 1825 host, resulted in high helical twisting power product(s). Selectivity of the reaction with the isothiocyanate-based liquid crystal was found. [ABSTRACT FROM AUTHOR]

Near infrared (NIR) light offers high transparency in biological tissue. Recent advances in NIR fluorophores including organic dyes and lanthanide-doped inorganic nanoparticles have realized the effective use of the NIR optical window for in vivo bioimaging and photodynamic therapy. The narrow energy level intervals used for electronic transition that involves NIR light, however, give rise to a need for guidelines for reducing heat emission in luminescence systems, especially in the development of organic/inorganic hybrid structures. This review presents an approach for employing the polarity and vibrational energy of ions and molecules that surround the luminescence centers for the development of such hybrid nanostructures. Multiphonon relaxation theory, formulated for dealing with heat release in ionic solids, is applied to describe the vibrational energy in organic or molecular systems, referred to as phonon in this review, and we conclude that surrounding the luminescence centers either with ions with low vibrational energy or molecules with small chemical polarity is the key to bright luminescence. NIR photoexcited phosphors and nanostructures in organic/inorganic mixed systems, designed based on the guidelines, for photodynamic therapy are reviewed. [ABSTRACT FROM AUTHOR]

The handling of inorganic scintillators (e.g., alkali metal halides) can benefit from the availability of polymeric materials able to adhere to their surface. Polymeric materials, such as epoxy resins, can act as protective coatings, as adhesives for photodiodes to be connected with the scintillator surface, and as a matrix for functional fillers to improve the optical properties of scintillators. Here, the optical properties of two epoxy resins (E-30 by Prochima, and Technovit Epox by Heraeus Kulzer) deposited on the surface of a scintillator crystal made of CsI(Tl) were investigated, in order to improve the detection of high-energy radiation. It is found that these resins are capable of adhering to the surface of alkali metal halides. Adhesion, active at the epoxy–CsI(Tl) interface, can be explained on the basis of Coulomb forces acting between the ionic solid surface and an ionic intermediate of synthesis generated during the epoxy setting reaction. Technovit Epox showed higher transparency, and it was also functionalized by embedding white powdered pigments (PTFE or BaSO4) to achieve an optically reflective coating on the scintillator surface. [ABSTRACT FROM AUTHOR]

Ion Conductors Na- "-alumina (Na SB 2 sb O~6Al SB 2 sb O SB 3 sb ) is known to be an excellent sodium ion conductor, which is used in sodium-sulfur batteries, sodium-nickel chloride batteries, alkali metal thermoelectric converters, and in sensors. The former are studied, for example, as electrode materials for protonic ceramic fuel/electrolysis cells (PCFCs/PCECs) or solid oxide fuel/electrolysis cells (SOFCs/SOECs), while the latter are ideal electrolytes for the same technologies. Functional ceramic materials are of interest in many applications due to their structural and chemical richness and the huge range of physical properties that can be generated and modified by the control of the former (electrical conductivity, thermo-mechanical properties, dielectric, piezoelectric, ferroelectric properties, etc.). [Extracted from the article]

The influence of Linus Pauling on the understanding of chemical bonding is critically examined. Pauling deserves credit for presenting a connection between the quantum theoretical description of chemical bonding and Gilbert Lewis's classical bonding model of localized electron pair bonds for a wide range of chemistry. Using the concept of resonance that he introduced, he was able to present a consistent description of chemical bonding for molecules, metals, and ionic crystals which was used by many chemists and subsequently found its way into chemistry textbooks. However, his one-sided restriction to the valence bond method and his rejection of the molecular orbital approach hindered further development of chemical bonding theory for a while and his close association of the heuristic Lewis binding model with the quantum chemical VB approach led to misleading ideas until today. [ABSTRACT FROM AUTHOR]