Anion Of Salt Research Articles

Preparation, QTAIM and Single‐Crystal Exploration of the Pyrimethamine‐Based Co‐Crystal Salts with Substituted Benzoic Acids

AbstractThe effective preparation of pyrimethamine based co‐crystal salts with substituted benzoic acids (4‐nitrobenzoic acid 1 and 5‐chlorosalicylic acid 2) in methanol has been reported. The crystal structure of salt 1 and 2 is acquired through the x‐rays diffraction technique. Hirshfeld surface analysis elaborates the comparative study of the non‐covalent interactions in salt 1 and 2. In order to theoretically evaluate the non‐covalent interactions between molecular ions in salts 1 and 2, DFT and TD‐DFT calculations of molecular salts were performed. FMO and GRD analyses were performed to evaluate the reactivity of molecular ions. While, NBO, AIM and NCI analyses were performed to explore the non‐covalent interactions between cation and anions of molecular salts 1 and 2. The calculations demonstrated that salt 1 has H‐bond slightly stronger than salt 2 due to the withdrawing effect of ‐NO2 substituent group. The molecular anions reactivity allows different patterns of non‐covalent interactions that affect the salts arrangement in the crystal.

Saturated salt solutions in showcases: humidity control and pollutant absorption

The sustainable, passive climatisation of display cases using saturated salt solutions is rarely applied nowadays. These solutions adjust the atmospheric humidity to the specific deliquescence relative humidity (DRH) of the salt. Practical problems like the risk of spilling or ‘creeping’ of salts can be overcome. The DRH of suitable salts does not depend significantly on temperature. Solutions were Oddy-tested to check for corrosive emissions of the acids corresponding to the salt anions. Only magnesium chloride failed in accordance with thermodynamic calculations of the HCl vapour pressure. Solutions can absorb water-soluble pollutants like acids or aldehydes from the atmosphere, as has successfully been demonstrated for formaldehyde in chamber experiments. The alkaline potassium carbonate solution not only dissolves acids and aldehydes but also reacts with them chemically. Research needs to further study the absorption of pollutants are outlined. A revival of the saturated salt solution would make museum displays more sustainable.

Understanding Dual‐Polar Group Functionalized COFs for Accelerating Li‐Ion Transport and Dendrite‐Free Deposition in Lithium Metal Anodes

Lithium metal batteries (LMBs) have attracted wide attentions because of their high theoretical specific capacity and low electrochemical potential. However, the growth of lithium dendrites seriously affects the practical application of LMBs. Thus, the lithium‐philic carbonyl and carboxy dual‐group‐modified covalent organic framework (COF‐COOH) is designed to coat the polypropylene (PP) separator (COF‐COOH@PP separator), realizing the regulation of ion transport and uniform lithium deposition. The plentiful and negative charge sites in the COF‐COOH can suppress the diffusion of the freely movable lithium salt anion by the electrostatic interaction. Density functional theory (DFT) calculations demonstrate that the COF‐COOH possesses the function of anchoring anion and desolvation. Consequently, the Li+ transference number (0.7), ion conductivity (0.64 mS cm−1), and desolvating of Li+ are obviously improved by using the COF‐COOH@PP separator. The modified Li‐Li symmetric battery delivers stable cycle for more than 1000 h and lower voltage hysteresis (0.02 V). This dendrite‐free deposition strategy holds great promise for practical application of Li metal anodes.

Effects of soluble products decomposed from chelato-borate additives on formation of solid electrolyte interface layers

The prevailing account attributes the positive effects of boron-based additives on solid electrolyte interface (SEI) layers to its solid products by prior decomposition. However, this study proves the BOF2− anion, a soluble product of film formation additive of lithium difluoro(oxalato)borate, plays a crucial role in improving the SEI layer. Specifically, BOF2− suppresses the excessive decomposition of salt anions by aggregating on the electrode surface. Meanwhile, it catalyzes the reduction of ethylene carbonate, leading to improving the stability of the interface. In the end, ultrasound shaking is used to generate more BOF2− anion and increase the cycle performance of cells at a high rate as excepted. This work helps to understand the effects of soluble products on the SEI forming process and provides new insights for improving the stability of electrode electrolyte interfaces.

Field theory of structured liquid dielectrics

We develop a field-theoretic approach for the treatment of both the nonlocal and the nonlinear response of structured liquid dielectrics. Our systems of interest are composed of dipolar solvent molecules and simple salt cations and anions. We describe them by two independent order parameters, the polarization field for the solvent and the charge-density field for the ions, including and treating the nonelectrostatic part of the interactions explicitly and consistently. We show how to derive functionals for the polarization and the electrostatic field of increasingly finer scales and solve the resulting mean-field saddle-point equations in the linear regime. We derive criteria for the character of their solutions that depend on the structural lengths and the polarity of the solvent. Our approach provides a systematic way to derive generalized polarization theories.

Activated metal-organic frameworks (a-MIL-100 (Fe)) as fillers in polymer electrolyte for high-performance all-solid-state lithium metal batteries

As a common filler in polymer electrolytes, Metal-organic frameworks (MOFs) has been studied extensively in recent years. In this study, we propose a novel solid composite electrolytes (SCEs) based on PEO/LiTFSI/a-MIL-100 (Fe)/PVDF by using a straightforward solution-casting method. Unactivated and activated MIL-100 (Fe) (a-MIL-100 (Fe)) as the fillers were compared, and the interactions of functional groups of unactivated MIL-100 (Fe) and a-MIL-100 (Fe) with anions of electrolyte salts through Lewis acid-base interaction are studied with density functional theory (DFT) calculations. The influences of different a-MIL-100 (Fe) contents on electrochemical performances were also examined. The Li/SCEs/LiFePO4 cell displayed high average discharge capacities of 161.8 mAh g−1, 166.8 mAh g−1, 158.9 mAh g−1, 146.2 mAh g−1 and 92.6 mAh g−1 at the rate of 0.1, 0.2, 0.5, 1 and 2 C at 60 ℃, respectively, without liquid electrolytes. This work might provide new insight into the role of activated MOFs fillers in polymer electrolytes.

Influence of different salts of alkali and alkaline earth metals on the pyrolysis of Prosopis juliflora

AbstractThis study explores the effect of acetate, oxide and chloride salts of alkali and alkaline earth metals (AAEMs) on the pyrolysis of lignocellulosic biomass. Prosopis juliflora samples were infused using 2% acetate and chloride salts of potassium (CH3COOK, KCl) and the oxide and chloride salts of magnesium (MgO, MgCl2). Dry impregnation technique was employed for the infusion of salts into the biomass matrix. The AAEM salt‐infused biomass was pyrolyzed using a semi‐batch pyrolysis reactor, and the bio‐oils were characterized for variation in chemical composition using gas chromatography–mass spectroscopy. The AAEM salts significantly influenced the pyrolysis process by catalyzing different degradation pathways. Potassium salts catalyzed the ring fission reactions of carbohydrates, resulting in an increase in carboxylic acid yield. On the other hand, magnesium salts promoted the cyclization of the fragmented radicals of the ring fission, resulting in enhanced furan and cycloketone yield. AAEM salts were most effective in catalyzing carbohydrate degradation pathways over the lignin degradation reactions owing to their ability to easily influence polysaccharide C–C bond cleavage over those of lignin aromatic rings. This study also revealed that the anions of AAEM salts also play a major role in biomass pyrolysis. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd

Electron-Rich Diruthenium Complexes with π-Extended Alkenyl Ligands and Their F4 TCNQ Charge-Transfer Salts.

The synthesis of dinuclear ruthenium alkenyl complexes with {Ru(CO)(P i Pr3)2(L)} entities (L=Cl− in complexes Ru2‐3 and Ru2‐7; L=acetylacetonate (acac−) in complexes Ru2‐4 and Ru2‐8) and with π‐conjugated 2,7‐divinylphenanthrenediyl (Ru2‐3, Ru2‐4) or 5,8‐divinylquinoxalinediyl (Ru2‐7, Ru2‐8) as bridging ligands are reported. The bridging ligands are laterally π‐extended by anellating a pyrene (Ru2‐7, Ru2‐8) or a 6,7‐benzoquinoxaline (Ru2‐3, Ru2‐4) π‐perimeter. This was done with the hope that the open π‐faces of the electron‐rich complexes will foster association with planar electron acceptors via π‐stacking. The dinuclear complexes were subjected to cyclic and square‐wave voltammetry and were characterized in all accessible redox states by IR, UV/Vis/NIR and, where applicable, by EPR spectroscopy. These studies signified the one‐electron oxidized forms of divinylphenylene‐bridged complexes Ru2‐7, Ru2‐8 as intrinsically delocalized mixed‐valent species, and those of complexes Ru2‐3 and Ru2‐4 with the longer divinylphenanthrenediyl linker as partially localized on the IR, yet delocalized on the EPR timescale. The more electron‐rich acac− congeners formed non‐conductive 1 : 1 charge‐transfer (CT) salts on treatment with the F4TCNQ electron acceptor. All spectroscopic techniques confirmed the presence of pairs of complex radical cations and F4TCNQ.− radical anions in these CT salts, but produced no firm evidence for the relevance of π‐stacking to their formation and properties.

Sequential Reduction of Borylstibane to an Electronically Nonsymmetric Diboryldistibene Radical Anion.

Understanding the formation of metal-metal bonds and their electronic structures is still a scientific task. We herein report on the stepwise synthesis of boryl-substituted antimony compounds in which the antimony atoms adopt four different oxidation states (+III, +II, +I, +I/0). Sb-C bond homolysis of Cp*[(HCNDip)2B]SbCl (1; Cp* = C5Me5; Dip = 2,6-iPr2C6H3) gave diboryldichlorodistibane [(HCNDip)2BSbCl]2 (2), which reacted with KC8 to form diboryldistibene [(HCNDip)2BSb]2 (3) and traces of cyclotetrastibane [(HCNDip)2B]3Sb4Cl (5). One-electron reduction of 3 yielded the potassium salt of the diboryldistibene radical anion [(HCNDip)2BSb]2̇-, [K(18-c-6)(OEt2)][{(HCNDip)2BSb}2] (4), which exhibits an unprecedented inequivalent spin localization on the Sb-Sb bond and hence an unsymmetric electronic structure. Compounds 1-4 were characterized by heteronuclear nuclear magnetic resonance (NMR) (1H, 13C, 11B), infrared (IR), ultraviolet-visible (UV-vis) spectroscopy (3, 4), and single crystal X-ray diffraction (sc-XRD, 1-5), while the bonding nature of 3 and 4 was analyzed by quantum chemical calculations. EPR spectroscopy resolves the dissimilar Sb hyperfine tensors of 4, reflecting the inequivalent spin distribution, setting 4 uniquely apart from all previously characterized dipnictene radical anions.

In Situ UV–Vis Analysis of Polysulfide Shuttling in Ionic Liquid-Based Li-FeS2 Batteries

Herein, a combination of in situ and ex situ UV–Vis spectroscopy is used to study the formation and shuttling of polysulfides (PSs) in Li-FeS2 batteries. We find three key results. First, PS shuttling significantly decreases (∼4×) when an ionic liquid electrolyte (1.0 M LiFSI in PYR14TFSI; ILE) is used in place of a conventional organic electrolyte (1.0 M LiTFSI in 1:1 DOL:DME). Furthermore, when the Li salt anion in the ILE is changed from FSI– to TFSI–, PS shuttling is effectively suppressed. Second, the total amount of PSs formed using the ILE is approximately double the amount shuttled. This result has implications for battery aging as solubility of PSs could conceivably increase upon extended storage. Third, the majority of PS shuttling occurs during the first cycle. Together, these findings provide important insights for understanding and thus preventing PS shuttling in Li-FeS2 batteries.

Bis(fluorosulfonyl)imide-based electrolyte for rechargeable lithium batteries: A perspective

The inherent properties of non-aqueous electrolytes are highly associated with the identity of salt anions. To build highly conductive and chemically/electrochemically robust electrolytes for lithium-ion batteries (LIBs) and rechargeable lithium metal batteries (RLMBs), various kinds of weakly coordinating anions have been proposed as counterparts of lithium salts and ionic liquids. Among them, bis(fluorosulfonyl)imide anion ([N(SO2F)2]−, FSI−) has aroused special attention in battery field due to the unique physical, chemical, and electrochemical properties of the FSI-based electrolytes. Herein, an overview on the synthetic methodologies of the FSI-based salts (e.g., alkali metal salts, ionic liquids) is provided, and their applications in LIBs and RLMBs are also updated. Future directions on developing FSI-based and/or FSI-derived electrolytes are presented. The present work is anticipated to inspire the design and screening of new anions for battery use, particularly, those stemming from sulfonimide anions.

Charge transfer complexes as dual thermal/photo initiators for free‐radical frontal polymerization

AbstractFrontal polymerization is a process in which a localized reaction zone propagates from the coupling of thermal transport and the Arrhenius rate dependence of an exothermic polymerization; monomer is converted into polymer as the front passes through an unstirred medium. Herein we report the first study of charge transfer complexes (CTCs) as photo/thermal initiators for free‐radical frontal polymerization. Front velocity was studied as a function of mole ratio between an aromatic amine, such as dimethyl‐p‐toluidine or dimethylaniline, and an iodonium salt. It was found that the front velocity reached a maximum at a certain mole ratio of amine to iodonium salt. The velocity remained constant upon increasing the ratio of amine to iodonium salt past this critical ratio. Fronts were also studied using N‐phenyl glycine as an electron donor, but its utility was limited by low solubility. Lastly, the steric and electronic effects of the iodonium salt and counter anion were explored. It was found that CTCs using iodonium salts with less nucleophilic anions gave higher front velocities. In terms of intrinsic reactivity, the CTC composed of N,N‐dimethyl‐p‐toluidine and bis[4‐(tert‐butyl)phenyl]iodonium tetra(nonafluoro‐tert‐butoxy)aluminate gave the highest front velocity per molal of iodonium salt.

Further study on energetic salts of TNATT anion

Six energetic salts based on fully nitroamino-functionalized fused-triazole were synthesized. All salts were characterized by IR, multinuclear NMR spectroscopy, thermal analysis and elemental analysis. The crystal structures of salts 2, 3, and 6 were confirmed by single-crystal X-ray diffraction. The densities of all salts lie in the range between 1.77 and 1.83 g cm−3, whilst their decomposition temperatures range within 142–200 °C. Most energetic salts are slightly more sensitive than RDX. The calculated detonation pressures and velocities (Gaussian 09 and EXPLO5) of salts 2–7 range within 21.7–39.3 Gpa and 7867–9401 m s−1, respectively. Salt 7 exhibits a high density (1.83 g cm−3), acceptable thermal stability (Td = 179 °C) and sensitivity (IS = 7 J, FS = 216 N), and excellent detonation performance (vD = 9401 m s−1, P = 39.3 GPa), which suggest that salt 7 may well have promising applications as high-energy–density materials.

Intriguing Cytotoxicity of the Street Dissociative Anesthetic Methoxphenidine: Unexpected Impurities Spotted.

The black market for new psychoactive substances has been constantly evolving and the substances that appear on this market cause a considerable number of issues, in extreme cases leading to human deaths. While monitoring the drug black market, we detected a sample of a dissociative anesthetic methoxphenidine, the salt of which contained an unusual anion in the form of bromo- and chloro-zincate complex. Concerning the unknown and potentially hazardous properties of this sample, we performed an in vitro cytotoxicity screening in cell lines of various origins (e.g., kidney, liver, bladder) which was compared with the toxicity results of the methoxphenidine standard prepared for this purpose. The street methoxphenidine sample exhibited markedly higher toxicity than the standard, which was probably caused by the anion impurity. Since it is not usual to analyze anions in salts of novel psychoactive substances, but such samples may be commonly available at the drug black market, we have developed a method for their identification with X-ray powder diffraction (XRPD), which also enabled us to distinguish between different polymorphs/solvates of methoxphenidine that were crystallized in the laboratory. XRPD offers additional data about samples, which may not be discovered by routine techniques, and in some cases, they may help to find out essential information.

Stable non-corrosive sulfonimide salt for 4-V-class lithium metal batteries.

Rechargeable lithium metal (Li0) batteries (RLMBs) are considered attractive for improving Li-ion batteries. Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) has been extensively used as a conducting salt for RLMBs due to its advantageous stability and innocuity. However, LiTFSI-based electrolytes are corrosive towards aluminium (Al0) current collectors at low potentials (>3.8 V versus Li/Li+), thereby excluding their application in 4-V-class RLMBs. Herein, we report on a non-corrosive sulfonimide salt, lithium (difluoromethanesulfonyl)(trifluoromethanesulfonyl)imide (LiDFTFSI), that remarkably suppresses the anodic dissolution of the Al0 current collector at high potentials (>4.2 V versus Li/Li+) and significantly improves the cycling performance of Li(Ni1/3Mn1/3Co1/3)O2 (NMC111) cells. In addition, this sulfonimide salt results in the growth of an advantageous solid electrolyte interphase on the Li0 electrode. The replacement of either LiTFSI or LiPF6 with LiDFTFSI endows a Li0||NMC111 cell with superior cycling stability and capacity retention (87% at cycle 200), demonstrating the decisive role of the salt anion in dictating the electrochemical performance of RLMBs.

High-entropy metal oxide containing hybrid electrolyte for long-life Li-metal batteries

AbstractSolid-state electrolytes are responsible for transporting lithium (Li) ions between electrodes in solid-state batteries and are essential for high-safety and high-energy Li-metal batteries. Developing novel solid-state electrolytes with high ionic conductivity and good interfacial contact is an urgent need. Here, to this end, a solid-state hybrid electrolyte is developed by mixing high-entropy Li-containing metal oxide (Lix(Mg0.2Co0.2Ni0.2Cu0.2Zn0.2)1−xO, HEOLi) matrix and poly(ethylene oxide)–Li salt binder and casting on polytetrafluoroethylene (PTFE) substrate. By virtue of the low Li-ion migration energy barrier of the HEOLi (0.36 eV) and the strong interaction between the oxygen vacancies of the HEOLi and the Li salt anions, a biphasic transport of Li ions in both inorganic and polymeric phases of the hybrid electrolyte is achieved, yielding a high ionic conductivity of 3 × 10−4 S cm−1 at 30°C. The Li/Li symmetric cells with the hybrid electrolyte show a low overpotential of 45 mV and a long cycle life of more than 2500 h. Furthermore, coupled with the LiFePO4 cathodes and metallic Li anodes, solid-state full cells with the hybrid electrolyte deliver a high capacity of 150 mAh g−1, stable cycle performance and high safety. Consequently, hybrid electrolytes based on high-entropy metal oxides have broad application prospects in solid-state electrochemical energy storage and are expected to achieve Li-metal batteries with high-safety, high-energy density and long life.

Facile Construction of Cu/ZnO Heterojunctions for Enhanced Photocatalytic Performance

The design and construction of semiconductor–metal heterojunctions are being considered to be an effective way to overcome the limited visible-light absorption of semiconductors. Herein, a facile and scale approach is reported for the first time to synthesize Cu/ZnO heterojunctions by one-step galvanic replacement between Zn and cuprous solution reaction. Two kinds of morphologies Cu/ZnO heterojunctions could be obtained by changing cuprous salt anion such as Br−, Cl− and I−. A flower-like Cu/ZnO heterostructured is chosen as a representative to demonstrate the facility and enhanced photocatalytic performance toward Rhodamine B degradation under visible-light irradiation. Results showed flower-like Cu/ZnO heterojunctions have higher photocatalytic performance than the other two morphologies. The galvanic replacement growth mechanism of Cu/ZnO heterojunctions was also further investigated. It is found that Cu/ZnO heterojunctions formed from Zn and Cu2O at an acid solution and room condition. This work indicates that galvanic replacement reaction at room temperature is an excellent technique to grow Cu/ZnO heterojunctions and demonstrates that the hole and electron transfer between Cu and ZnO can efficiently enhance their photocatalytic performance. This general method can also be further explored to guide the design of metal/metal oxide heterostructured on other substrates, such as Zn, Ni and Cu foils.

Influence of free F− anions on evaporation behavior of molten salts containing ZrF4

The evaporation behavior of FLiNaK and FLiBe molten salts containing 5mol% ZrF4 was investigated by low pressure distillation method. It was found that compared with pure FLiNaK salt, the evaporation rates of LiF, NaF and KF decreased sharply in the ZrF4-FLiNaK salt; while in the case of ZrF4-FLiBe salt, the evaporation rate of LiF decreased to a certain degree, and that of BeF2 was almost the same as FLiBe salt without addition of ZrF4. XRD results showed that the fluorine were present as free anions in pure FLiNaK salt, while the formation of BeF42− existed in pure FLiBe salt. After the addition of ZrF4, the complexes of K3ZrF7 and Li2ZrF6 were observed in FLiNaK and FLiBe salts, respectively. The microstructure of salts showed the difference of coordinate numbers and activation energies of Zr-F by molecular dynamics (MD) simulation, which affected the evaporation behavior of the material.

Indeno[2,1-a]fluorene-11,12-dione Radical Anions: Synthesis, Characterization, and Properties.

The one-electron reduction of indeno[2,1-a]fluorene-11,12-dione (IF) with various alkali metals prepare the radical anion salts. The data about different structures, properties, and characterization was obtained by single-crystal X-ray diffraction, electron paramagnetic resonance (EPR) spectroscopy, superconducting quantum interference device (SQUID) measurements, and physical property measurement system (PPMS). Compound IF.- K+ (18-c-6) is regarded as a one-dimensional magnetic chain through C-H⋅⋅⋅C interaction. Theoretical calculations and magnetic results showed that [IF.- K+ (15-c-5)]2 is a dimer with an open-shell ground state. Compounds IF.- Na+ (15-c-5) and IF.- K+ (cryptand) are monoradical anion salts: IF2 .- Li+ possesses unique π-stack structure with an interplanar separation less than 3.46 Å, making it a semiconductor (δRT =1.9×10-4 S ⋅ cm-1 ). This work gives insights into multifunctional radical anions, and describes the design and development of different functional radicals.

Effect of the supergravity on the formation and cycle life of non-aqueous lithium metal batteries

Extra-terrestrial explorations require electrochemical energy storage devices able to operate in gravity conditions different from those of planet earth. In this context, lithium (Li)-based batteries have not been fully investigated, especially cell formation and cycling performances under supergravity (i.e., gravity > 9.8 m s−2) conditions. To shed some light on these aspects, here, we investigate the behavior of non-aqueous Li metal cells under supergravity conditions. The physicochemical and electrochemical characterizations reveal that, distinctly from earth gravity conditions, smooth and dense Li metal depositions are obtained under supergravity during Li metal deposition on a Cu substrate. Moreover, supergravity allows the formation of an inorganic-rich solid electrolyte interphase (SEI) due to the strong interactions between Li+ and salt anions, which promote significant decomposition of the anions on the negative electrode surface. Tests in full Li metal pouch cell configuration (using LiNi0.8Co0.1Mn0.1O2-based positive electrode and LiFSI-based electrolyte solution) also demonstrate the favorable effect of the supergravity in terms of deposition morphology and SEI composition and ability to carry out 200 cycles at 2 C (400 mA g−1) rate with a capacity retention of 96%.