Cation Salts Research Articles

Kinetics of ion-mediated directed self-assembly of one-dimensional chains of metal nanoparticles in solution.

The synergistic optical, electronic, and chemical properties of metal nanoparticles present in close proximity have potential applications in energy, medicine, and sustainability. Fundamental studies and application development based on spontaneous self-assembly of one-dimensional (1D) chains of metal nanoparticles without external organization agencies have been pursued for over four decades. The spontaneous formation of 1D chains in a solution of stabilized spherical nanoparticles may be driven by the emergence of local anisotropy due to dipolar interaction, representing a trapped non-equilibrium state. Here, the kinetics of this broken symmetry in the "directed" self-assembly of spherical particles is studied to form a 1D chain. The 1D chain assembly of 10 nm Au particles that had been stabilized by electrostatic repulsion is initiated by adding a small amount of divalent cation salt. A phenomenological model is presented to explain the transition state controlling the kinetics of the 1D self-assembly. Experimental and simulation studies were combined to measure the kinetics of the chain growth over time which revealed a sharp transition between two growth processes that were analogous to addition and condensation polymerization.

Broken Symmetry and Elastic Frustration in Isostructural MnIII Spin Crossover Crystals.

Symmetry breaking spin state transitions in two of three isostructural salts of MnIII spin crossover cations, [MnIII(3-OMe-5-NO2-sal2323)]+, with heavy anions are reported. The ReO4 - (1) salt undergoes two-step spin crossover which is coupled with a re-entrant symmetry breaking structural phase transition between a high temperature phase (S=2, C2/c), an intermediate ordered phase (S=1/S=2, P21/c), and a low temperature phase (S=1, C2/c). The AsF6 - (2) complex undergoes an abrupt transition between a high temperature phase (S=2, C2/c) and a low temperature ordered phase (S=1/S=2, P ). The SbF6 - (3) complex undergoes a gradual transition between a high temperature phase (S=2, P ) and a low temperature spin state ordered phase (S=1/S=2, P- ). Correlation of the volume of the anion and the T1/2 of the transitions in these complexes and three analogous complexes with similar anions, BF4 - (4), ClO4 - (5), PF6 - (6), reveals an increase in T1/2 upon increasing the anion volume. We rationalise that the volume of the anions used modulates the elastic interactions between the MnIII sites in the lattice, with increasing elastic frustration with the larger anions resulting in a two-stepped transition for 1 and the stabilisation of the mixed (HS:LS) state to low temperature for 2 and 3.

Abstraction of Hydride from Alkanes and Dihydrogen by the Perfluorotrityl Cation.

Lewis acids play a central role in a large variety of chemical transformations. The reactivity of the strongest Lewis acids is typically studied in the context of affinity towards hard bases, such as fluoride or oxygenous species. Carbocations can be viewed as soft Lewis acids, possessing significant affinity for softer bases, such as hydride. This work presents the ambient-temperature isolation of salts of the perfluorotrityl cation ((C6F5)3C+ or F15Tr+) in combination with halogenated carborane anions. The F15Tr+ cation exhibits remarkable hydride affinity, illustrated by the observation of hydride abstraction from dihydrogen, and of the rapid abstraction of hydride from -CH2- groups in alkanes. Theoretical studies support the favorability of hydride abstraction from dihydrogen, and indicate that the hydride abstraction from alkanes proceeds via a concerted hydride transfer process that is sensitive to steric effects.

Influence of Added Cellulose Nanocrystals on the Rheology of Polymers.

The interactions between cellulose nanocrystals and six different polymers (three anionic, two non-ionic, and one cationic) were investigated using rheological measurements of aqueous solutions of nanocrystals and polymers. The experimental viscosity data could be described adequately by a power-law model. The variations in power-law parameters (consistency index and flow behavior index) with concentrations of nanocrystals and polymers were determined for different combinations of nanocrystals and polymers. The interactions between nanocrystals and the following polymers: anionic sodium carboxymethyl cellulose and non-ionic guar gum, were found to be strong in that the consistency index increased substantially with the addition of nanocrystals to polymer solutions. The interaction between nanocrystals and non-ionic polymer polyethylene oxide was moderate. Depending on the concentrations of nanocrystals and polymer, the consistency index both increased and decreased upon the addition of nanocrystals to polymer solution. The interactions between nanocrystals and the following polymers: anionic xanthan gum, anionic polyacrylamide, and cationic quaternary ammonium salt of hydroxyethyl cellulose, were found to be weak. The changes in rheological properties with nanocrystal addition to these polymer solutions were found to be small or negligible.

Isolation and characterization of the dimetal decacarbonyl dication [Ru2(CO)10]2+ and the metal-only Lewis-pair [Ag{Ru(CO)5}2]+ .

The reaction of Ag+ with Ru3(CO)12 in a CO atmosphere under concommittant irradiation with UV-light yields a salt of the metal-only Lewis-pair [Ag{Ru(CO)5}2]+. Switching the silver cation for a more process-selective deelectronator yields a salt of the homoleptic transition metal carbonyl cation [Ru2(CO)10]2+, which fills the gap between the known cations [Ru(CO)6]2+ and [Ru3(CO)14]2+. The amount of π-backdonation in this series was studied by a combination of vibrational spectroscopy and computed relaxed force constants.

Cationic chitosan enables eutectogels with high ionic conductivity for multifunctional applications in energy harvesting and storage

Eutectogels are popular as an emerging material in the field of flexible electronics. However, limited mechanical properties and ionic conductivity restrict their multifunctional application expansion. Herein, cationic chitosan quaternary ammonium salt (CQS) was evenly embedded into the three-dimensional porous framework of eutectogel to build ion migration channels. And a simple solvent replacement process enhanced the crystallization of polyvinyl alcohol matrix and hydrogen bonding, preparing composite eutectogels with high toughness, environmental tolerance and conductivity. The prepared gel exhibites excellent mechanical properties (1.72 MPa, 413 %) and conductivity (0.40 S·m−1). Under external force, three-dimensional porous network with cationic polysaccharide distribution can achieve effective piezoionic effect. Moderate CQS significantly enhances the piezoionic voltage output to 270 mV, which is 4.5 times that of the pure eutectogel. Further, the prepared composite eutectogels was used for capacitor energy storage and wearable sensing devices, and has good charge/discharge stability (94 % capacitance retention) and fast response time (292 ms). This design is typically suitable for preparing advanced multifunctional ion conductors using various natural polysaccharides with sustainable application potential.

A series of enantiopure BEDT-TTF-acetamide derivatives with two stereogenic centres

Synthesis of enantiopure BEDT-TTF donors with two stereogenic centres and hydrogen bonding functionality, and formation of their first radical cation salts.

Effects of cation types on physicochemical parameters and micro-structure of soft clay for electrochemical treatment

To investigate the influence of cations on the microstructural characteristics of electrochemical reinforcement in soft clay, a study was conducted using three different cationic salt solutions—NaCl, CaCl₂, and FeCl₃—for grouting treatment. Four sets of indoor experiments were performed to examine the reinforcement mechanism of the electrochemical method. The findings indicate that increasing the valence of injected cations significantly affects the electrochemical reinforcement effect and the soil’s microstructural properties. Higher-valence cations notably enhanced the soil’s electrical permeability coefficient and conductivity, leading to a substantial improvement in shear strength. Furthermore, the pore volume of the soil increased following electrochemical treatment compared to soil treated solely by electro-osmosis, due to the flocculation effect induced by cation injection. Nevertheless, the pore size distribution became more uniform, especially in the cathode region, as a result of pore redistribution. The chemical cementation reactions triggered by Ca2+ and Fe3+ injections mitigated the impact of flocculation on the microstructure, resulting in a more favorable pore volume and size distribution compared to Na+ treatment.

Nanodots of Transition Metal Sulfides, Carbonates, and Oxides Obtained Through Spontaneous Co-Precipitation with Silica.

The controlled formation and stabilization of nanoparticles is of fundamental relevance for materials science and key to many modern technologies. Common synthetic strategies to arrest growth at small sizes and prevent undesired particle agglomeration often rely on the use of organic additives and require non-aqueous media and/or high temperatures, all of which appear critical with respect to production costs, safety, and sustainability. In the present work, we demonstrate a simple one-pot process in water under ambient conditions that can produce particles of various transition metal carbonates and sulfides with sizes of only a few nanometers embedded in a silica shell, similar to particles derived from more elaborate synthesis routes, like the sol-gel process. To this end, solutions of soluble salts of metal cations (e.g., chlorides) and the respective anions (e.g., sodium carbonate or sulfide) are mixed in the presence of different amounts of sodium silicate at elevated pH levels. Upon mixing, metal carbonate/sulfide particles nucleate, and their subsequent growth causes a sensible decrease of pH in the vicinity. Dissolved silicate species respond to this local acidification by condensation reactions, which eventually lead to the formation of amorphous silica layers that encapsulate the metal carbonate/sulfide cores and, thus, effectively inhibit any further growth. The as-obtained carbonate nanodots can readily be converted into the corresponding metal oxides by secondary thermal treatment, during which their nanometric size is maintained. Although the described method clearly requires optimization towards actual applications, the results of this study highlight the potential of bottom-up self-assembly for the synthesis of functional nanoparticles at mild conditions.

Li-TFSI free carbazole-based hole transport materials enable highly stable perovskite solar cells.

It is crucial to fabricate highly stable perovskite solar cells for further commercialization. Herein, a novel cationic salt OY(TFSI)2 as an effective p-dopant to replace Li-TFSI is synthesized and introduced into the hole transport layer to improve the long-term stability of the device.

Removal of Diesel from Aqueous Solutions by a Combined Adsorption and Microbial Degradation Process

Diesel contamination in water bodies poses a significant environmental challenge due to the toxic effects of its water-soluble fraction (WSF) on aquatic ecosystems and human health. The aim of this work was the design of a new technological procedure for the purification of water contaminated with the WSF of diesel. The procedure is based on the adsorption of organic pollution on an organozeolite, after which the biodegradation of the adsorbed pollutant takes place. The material for obtaining organozeolite was a natural zeolite from the Zlatokop deposit (Vranje, Serbia). The zeolitic surface was modified with hexadecyltrimethylammonium bromide (HDTMA-Br), a cationic quaternary ammonium salt. The adsorption experiments, with initial WSF concentrations of 2.5–25 mg/L, at pH 6 and at 20 C, were performed in a batch system using organozeolite, and the results showed that more than 90% of the WSF of diesel was removed, reaching equilibrium after 1 h. The maximum adsorbed capacity of organozeolite for the removal of the WSF of diesel fuel from water under the tested conditions was 22.2 mg/g. Equilibrium data were well fitted by a linear isotherm model, while a pseudo-second-order equation well fitted the kinetic data. After adsorption, a 15-day biodegradation experiment was carried out under batch conditions. The results showed that the examined consortium of microorganisms degraded 80% of the adsorbed contaminant. Additional respirometric analyses showed that, in parallel with the degradation of the contaminant, the degradation of the long-chain HDTMA ions at the surface of the organozeolite also occurred. To the best of our knowledge, this is the first study combining adsorption and biodegradation to remove the WSF of diesel from water.

Low Evaporation Enthalpy Ionic Covalent Organic Frameworks for Efficient Atmospheric Water Harvesting at Low Humidity.

Herein, we introduce a series of ionic covalent organic frameworks (iCOFs) with a focus on addressing the challenge of water collection at low relative humidity levels below 25%. These iCOFs are characterized by numerous hydrophilic sites and high water stability, enabling efficient water vapor adsorption even at relatively low humidity levels. Through the use of various hygroscopic salt cations and precise control of ion concentration within the pores, the water state within the iCOFs pores can be effectively managed. Among the iCOFs, TB-COF-Li stands out with an impressive adsorption capacity of 0.24 g g-1 from 0 to 22% RH. Notably, due to its ionic porous structure, TB-COF-Li exhibits a significantly lower enthalpy of evaporation, measured at 967.04 J g-1, compared to bulk water with an enthalpy of 2387.4 J g-1. Moreover, under simulated conditions of 1.5 solar intensity at 60 °C, the majority of the adsorbed water can be rapidly desorbed without the need for additional energy input. This efficient desorption process contributes to a high water collection rate of 0.092 g g-1 h-1 in the final atmospheric water harvesting device. The development of these iCOFs offers a promising and cost-effective solution for obtaining fresh water in arid regions.

Low Evaporation Enthalpy Ionic Covalent Organic Frameworks for Efficient Atmospheric Water Harvesting at Low Humidity

Herein, we introduce a series of ionic covalent organic frameworks (iCOFs) with a focus on addressing the challenge of water collection at low relative humidity levels below 25%. These iCOFs are characterized by numerous hydrophilic sites and high water stability, enabling efficient water vapor adsorption even at relatively low humidity levels. Through the use of various hygroscopic salt cations and precise control of ion concentration within the pores, the water state within the iCOFs pores can be effectively managed. Among the iCOFs, TB‐COF‐Li stands out with an impressive adsorption capacity of 0.24 g g‐1 from 0 to 22% RH. Notably, due to its ionic porous structure, TB‐COF‐Li exhibits a significantly lower enthalpy of evaporation, measured at 967.04 J g‐1, compared to bulk water with an enthalpy of 2387.4 J g‐1. Moreover, under simulated conditions of 1.5 solar intensity at 60 °C, the majority of the adsorbed water can be rapidly desorbed without the need for additional energy input. This efficient desorption process contributes to a high water collection rate of 0.092 g g‐1 h‐1 in the final atmospheric water harvesting device. The development of these iCOFs offers a promising and cost‐effective solution for obtaining fresh water in arid regions.

3-(2-Hy-droxy-eth-yl)-1-(4-nitro-phen-yl)-1H-benzo[d]imidazol-3-ium bromide.

The cation of the title salt, C15H14N3O3 +·Br-, has a dihedral angle of 24.26 (6)° between its fused imidazole and 4-nitro-phenyl rings and the N-C-C-O torsion angle associated with the hy-droxy-ethyl substituent is 60.15 (17)°. In the crystal, the bromide ions act as double acceptors for hydrogen bonds from a hydroxyl group (O-H⋯Br) and a fused imidazolium moiety (C-H⋯Br). Additionally, C-H⋯O hydrogen bonds between the phenyl group and hydroxyl oxygen atom create a two-dimensional supra-molecular network extending diagonally in the crystallographic bc plane.

Assessment of Cationic Salts and Inorganic Acids as Washing Agents for Cs-137 Removal from Radioactively Contaminated Electric Arc Furnace Dust

Assessment of Cationic Salts and Inorganic Acids as Washing Agents for Cs-137 Removal from Radioactively Contaminated Electric Arc Furnace Dust

Nickel Bis(dithiolene) Complexes and Tetrathiafulvalenes from Sterically Hindered Di‐ and Tetra‐Substituted Dithiine‐dithiolo‐thione Precursors

AbstractThree variants of 5,6‐dihydro‐1,4‐dithiin‐2,3‐(1’,3’‐dithiole‐2’‐thione) (dddt) bearing up to four substituents on the ethylene bridge have been obtained by hetero‐Diels‐Alder reaction. The substituted dddt derivatives have the advantage of providing modulation of the steric hindrance and stereogenic centres, and represent valuable intermediates for both tetrathiafulvalene (TTF) and metal‐dithiolene complexes. Within this work, disubstituted and tetrasubstituted dddt derivatives have been used for the synthesis of Ni(II) monoanionic and neutral complexes, as well as for tetra‐ and octa‐methylated EDT‐TTF and BEDT‐TTF (EDT=ethylenedithio, BEDT=bis(ethylenedithio)) derivatives. While the influence of the bulkiness and number of the substituents is observed in the solid state packing of both types of materials (complexes and TTF), the absence of the counterion in the case of the neutral complexes translated into increased intermolecular interactions between the donors and the formation of 1D and 2D layers. The two examples of tetrasubstituted TTF radical cation salts reported in here show semiconducting behaviour due to the formation of dimers and lateral interactions through the S atoms. Our findings highlight the importance of substitution on these type of dddt precursors and their potential for electroactive molecular materials.

Ring Expansion from 16‐Membered Macrocyclic Lactones Using Yamaguchi and Photoinduced Decarboxylative Radical Macrolactonization

This study describes a new strategy for synthesizing 31‐, 33‐, 46‐, and 48‐membered macrocyclic lactones from commercially available 16‐membered macrocyclic lactones using the Yamaguchi reaction and photoinduced decarboxylative radical macrolactonization. Despite challenges with the low solubility of substrates and the slow rate of photochemical radical cyclization, the preparation of enlarged macrocyclic lactones from 16‐membered macrocyclic lactones was successfully accomplished. Additionally, the effect of the Lewis acidity of the counter cation in the carboxylate salt provided mechanistic insights into the photoinduced decarboxylative radical macrolactonization.

Improved Charge‐Transfer Doping in Crystalline Polymer for Efficient and Stable Perovskite Solar Cells

AbstractPerovskite solar cells (PSCs) have significant potential for next‐generation photovoltaic technology applications. However, the instability of hole transport layers (HTLs) becomes the major obstacle to long‐term operational devices, which are affected by the intrinsic thermal instability and loose structure of hole transport materials, as well as the hygroscopicity and migration of dopants. Here, poly(3‐hexylthiophene‐2,5‐diyl) (P3HT) is used as a model crystalline polymer to thoroughly investigate effective p‐type doping strategies and the underlying mechanism. According to Hard–Soft‐Acid–Base theory, the soft base P3HT is more likely to form a stable Lewis acid–base adduct with the reactive soft acid radical, resulting in a strong charge‐transfer interaction, thereby enhancing conductivity and regulating the energy band of the HTL. Meanwhile, the radical cation salt can promote pre‐nucleation to optimize the crystallization orientation of P3HT. The resulting PSCs exhibited the efficiency of 25.16%, which is the highest efficiency reported so far based on doped P3HT. In addition, the resulting devices demonstrated excellent stability, maintaining 96.5%, 96%, and 91% of their initial efficiency after aging under continuous illumination for 2028 h, at 85 °C for 1080 h, and at maximum power point (MPP) tracking under continuous 1 Sun illumination at 85 °C for 528 h, respectively.

Effect of Ionic Surfactants on Kinetics and Mechanism of the Bi(III) Ion Electroreduction in the Mixed Aqueous-Organic Solutions of Supporting Electrolytes.

This work presents the results of a study on the effect of ionic surfactants: cationic hexadecyltriammonium bromide (CTAB) and anionic sodium salt of sulfonic acid (1OSASS) on the Bi(III) electroreduction process in mixed aqueous-organic supporting electrolyte solutions containing methanol. This study showed that the composition of the supporting electrolyte solution, particularly the methanol and surfactant concentrations, significantly affects the mechanism and rate of the Bi(III) ion electroreduction. Analysis of the influence of the indicated factors on the mechanisms and kinetics of metal ion electroreduction can contribute not only to the optimization of industrial electrochemical processes but also to the development of innovative technological solutions, such as advanced electrochemical materials and novel sensors. In these experiments, an innovative electrode made of cyclic renewable liquid silver amalgam (R-AgLAFE) was used as a working electrode, which stands out among classic mercury electrodes (HMDE type) due to the significant reduction in mercury consumption while maintaining similar performance.

Quantify the effects of water-soluble salts and available fractions of nutrient elements on mobility of cadmium in paddy soil: A case study of the Pearl River Delta

As one of the most toxic heavy metal, soil Cd mobility is crucial to understand Cd transfer in soil-crop system and ensure crop safety production. Water-soluble salts and available fractions of nutrient elements have important influence on soil Cd mobility. However, effects of multi-factor interactions in water-soluble salts and available fractions of nutrient elements on Cd mobility and their quantified contributions haven't been enough emphasized. In this study, conditional inference tree and random forest were adopted to quantify effects of water-soluble salts, available fractions of nutrient elements and their interactions on Cd mobility in paddy soil from Pearl River Delta. The results suggested that cations (K+, Mg2+ and Na+) in water-soluble salts exerted important influence on Cd mobility, especially K+. Cd mobility is enhanced with the increase of K+ concentration and cation exchange capacity and their interaction. Available Si is the primary factor affecting Cd mobility, followed by available K and easily reducible Mn. With increases of their concentrations, interaction of available K and available Si boosts Cd mobility. When available K concentration is higher than 122 mg kg−1, Cd mobility is primarily restricted by available Si. In general, cations improve Cd mobility through competitive adsorption with Cd in soil, and available Si affect Cd mobility by changing Cd fractionation. Therefore, measures can be taken to reduce Cd mobility in paddy soil and promote sustainable development of agriculture. Such as increasing application of organic fertilizer, reducing application of chemical fertilizer, and promoting straw carbonization to return to field and so on.