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Diamide macrocycles are valuable intermediates for the synthesis of aza crown compounds as well as more complex ligands such as various cryptands and cryptohemispherands. Their versatility in many fields, such as chemistry, biochemistry, biophysics, biology, agriculture, industry, medicine, molecular diagnosis, sensors, and phase transfer catalysts, has captured the interest of many. In the first step, 2,4-dimethylphenol was converted to the oxythiobis [4,6-dimethylphenyl] (1) by reacting with thionyl chloride. Then, oxythiobis [4,6-dimethyl phenoxy methyl acetate] (2) was obtained from the reaction of oxythiobis [4,6-dimethylphenyl] (1) with methyl chloroacetate. The reaction of oxythiobis [4,6-dimethyl phenoxy methyl acetate] (2), with a diethylenetriamine, produced the tri-aza dibenzo sulfoxide macrocyclic diamides (3). Bis [tri-aza dibenzo sulfoxide macrocyclic diamides] (4) was prepared from the reaction of tri-aza dibenzo sulfoxide macrocyclic diamides (3) with a suitable active compound such as diacid or dichloride. The structures of all synthesized compounds were characterized by 1H NMR, 13C NMR, FT-IR, and mass spectra. [ABSTRACT FROM AUTHOR]

The hydrophilic-lipophilic balance (HLB) of any surfactant determines its solubility. Selection of the ideal surfactant for a given application appears to be facilitated by a thorough understanding of the relationship between accurately measured or calculated HLB and physicochemical properties. In this study the HLB values of the mono-, bi- and bolaphilic derivatives of F-alkylated cyclic polyethylene glycol succinate were determined using the Griffin technique. It was investigated how the different applications of these surfactants can be distinguished by their HLB values. [ABSTRACT FROM AUTHOR]

Amphiphilic supramolecular materials based on biodegradable cyclodextrins (CDs) have been known to self‐assemble into different types of thermotropic liquid crystals, including smectic and hexagonal columnar mesophases. Previous studies on amphiphilic CDs bearing 14 aliphatic chains at the secondary face and 7 oligoethylene glycol (OEG) chains at the primary face showed that the stability of the mesophase can be rationally tuned through implementation of terminal functional groups to the OEG chains. Here, we report the syntheses of first examples of crown ether‐functionalized amphiphilic cyclodextrins that unexpectedly form thermotropic bicontinuous cubic phases. This constitutes the first reported examples of cyclodextrins forming such phases, which are potentially capable of 3D ion transport. Lithium composites were made to assess lithium conduction in the material. XRD revealed the added lithium salt destabilizes the cubic phase in favour of the smectic phase. Solid‐state NMR studies showed that these materials conduct lithium ions with a very low activation energy. [ABSTRACT FROM AUTHOR]

Direct lithium extraction from unconventional resources requires the development of effective adsorbents. Crown ether-containing materials have been reported as promising structures in terms of lithium selectivity, but data on adsorption in real, highly saline brines are scarce. Crown ether-grafted graphene oxides were synthesized using 2-hydroxymethyl-12-crown-4, hydroxy-dibenzo-14-crown-4 and epichlorohydrin as a source of anchoring groups. The obtained carbonaceous materials were used to prepare chitosan–polyvinyl alcohol composites. The prepared materials (and intermediate products) were characterized using FTIR, XRD, Raman spectroscopy and SEM-EDS methods. Adsorption tests were performed in a pure diluted LiCl solution ([Li] = 200 mg/kg) as well as in a real, highly saline oilfield brine ([Li] ≈ 220 mg/kg), and the distribution coefficients (Kd) were determined. The obtained results show that Kd in pure LiCl solution was in the range of 0.9–75.6, while in brine it was in the range of 0.2–2.3. The study indicates that the high affinity for lithium in pure LiCl solution is mostly associated with the non-selective interaction of lithium ions with the graphene oxide matrix (COOH groups). It was also shown that the application of dibenzo-14-crown-4 moiety to graphene oxide modification groups increases the affinity of the composite material for lithium ions compared to an analogous material containing 12-crown-4-ether groups. [ABSTRACT FROM AUTHOR]

Due to almost identical boiling points of benzene and cyclohexane, the extraction of trace benzene from cyclohexane is currently performed via the energy-intensive extractive distillation method. Their adsorptive separation by porous materials is hampered by their similar dimensions. Metal-organic frameworks (MOFs) with versatile pore environments are capable of molecular discrimination, but the separation of trace substrates in liquid-phase remains extremely challenging. Herein, we report a robust MOF (NKU-300) with triangular channels decorated with crown ether that can discriminate trace benzene from cyclohexane, exhibiting an unprecedented selectivity of 8615(10) for the mixture of benzene/cyclohexane (v/v = 1/1000). Remarkably, NKU-300 demonstrates exceptional selectivities for the extraction of benzene from cyclohexane over a wide range of concentrations of 0.1%–50% with ultrafast sorption kinetics and excellent stability. Single-crystal X-ray diffraction and computational modelling reveal that multiple supramolecular interactions cooperatively immobilise benzene molecules in the triangular channel, enabling superior separation performance. This study will promote the application of advanced sorbents with tailored binding sites for challenging industrial separations. [ABSTRACT FROM AUTHOR]

Crown ether is widely used in water purification because of its ring structure and good selective adsorption of specific heavy metals. However, its high cost and difficulty in recycling limit the purification of heavy metals in water. The anisotropic [2,4]-dibenzo-18-crown-6-modified bamboo pulp aerogel (DB18C6/PA) is successfully synthesized by microwave irradiation and directional freezing technology. The physical and chemical properties of DB18C6/PA are analyzed by FTIR, XPS, SEM, TEM, TGA, surface area and porosity analyzers. Single or multivariate systems containing Pb2+, Cu2+ and Cd2+ are used as adsorbents. The effects of the DB18C6 addition amount, pH, initial concentration and adsorption temperature on the adsorption of DB18C6/PA are systematically explored. Pseudo-first-order kinetic models, pseudo-second-order kinetic models and the isothermal adsorption models of Langmuir and Freundlich are used to fit the experimental data. The adsorption selectivity is analyzed from the distribution coefficient and the separation factor, and the adsorption mechanism is discussed. The results show that anisotropic DB18C6/PA has the characteristics of 3D directional channels, high porosity (97.67%), large specific surface area (103.7 m2/g), good thermal stability and regeneration (the number of cycles is greater than 5). The surface has a variety of functional groups, including a hydroxyl group, aldehyde group, ether bond, etc. In the single and multivariate systems of Pb2+, Cu2+ and Cd2+, the adsorption process of DB18C6/PA conforms to the pseudo-second-order kinetic model, and the results conform to the Freundlich adsorption isothermal model (a few of them conformed to the Langmuir adsorption isothermal model), indicating that chemical adsorption and physical adsorption are involved in the adsorption process, and the adsorption process is a spontaneous endothermic process. In the single solution system, the maximum adsorption capacities of Pb2+, Cu2+ and Cd2+ by DB18C6/PA are 129.15, 29.85 and 27.89 mg/g, respectively. The adsorption selectivity of DB18C6/PA on Pb2+, Cu2+ and Cd2+ is in the order of Pb2+ >> Cu2+ > Cd2+. [ABSTRACT FROM AUTHOR]

The crystal structure of the title compound, hexaaquanickel(II) dichloride–1,4,7,10,13,16-hexaoxacyclooctadecane–water (1/2/2), [Ni(H2O)6]Cl2·2C12H24O6·2H2O, is reported. The asymmetric unit contains half of the Ni(OH2)6 moiety with a formula of C12H32ClNi0.50O10 at 105 K and triclinic (P1) symmetry. The [Ni(OH2)6]2+ cation has close to ideal octahedral geometry with O—Ni—O bond angles that are within 3° of idealized values. The supramolecular structure includes hydrogen bonding between the water ligands, 18-crown-6 molecules, Cl− anions, and co-crystallized water solvent. Two crown ether molecules flank the [Ni(OH2)6]2+ molecule at the axial positions in a sandwich-like structure. The relatively symmetric hydrogen-bonding network is enabled by small Cl− counter-ions and likely influences the more idealized octahedral geometry of [Ni(OH2)6]2+.

The crystal structure of the title compound, hexaaquanickel(II) dichloride- 1,4,7,10,13,16-hexaoxacyclooctadecane-water (1/2/2), [Ni(H2O)6]Cl2- 2C12H24O6183;2H2O, is reported. The asymmetric unit contains half of the Ni(OH2) 6 moiety with a formula of C12H32CINi0.50O10 at 105 K and triclinic (P1) symmetry. The [Ni(OH2)6]2+ cation has close to ideal octahedral geometry with O-Ni-O bond angles that are within 3° of idealized values. The supra- molecular structure includes hydrogen bonding between the water ligands, 18-crown-6 molecules, Cl- anions, and co-crystallized water solvent. Two crown ether molecules flank the [Ni(OH2)6]2+ molecule at the axial positions in a sandwich-like structure. The relatively symmetric hydrogen-bonding network is enabled by small Cl- counter-ions and likely influences the more idealized octahedral geometry of [Ni(OH2)6]2+. [ABSTRACT FROM AUTHOR]

Thorium is a weak radioactive element, but the control of its concentration in natural aqueous systems is of great interest for health, because it is a toxic heavy metal. The present paper presents the recovery of thorium from diluted synthetic aqueous systems by nanofiltration. The membranes used for the nanofiltration of systems containing thorium species are composites containing 4′-Aminobenzo-15-crown-5 ether (ABCE) and sulfonated poly–etherether–ketone (sPEEK). The composite membranes (ABCE–sPEEK) were characterized by scanning electron microscopy (SEM), energy-dispersive X–Ray spectroscopy (EDAX), thermal analysis (TG and DSC), and from the perspective of thorium removal performance. To determine the process performance, the variables were the following: the nature of the composite membrane, the concentration of thorium in the aqueous systems, the rotation speed of the stirrer, and the pressure and the pH of the thorium aqueous system. When using pure water, a permeate flux value of 12 L·m−2 h−1 was obtained for the sPEEK membrane, and a permeate flux value of up to 15 L·m−2 h−1 was obtained for the ABCE–sPEEK composite membrane. The use of mechanical stirring, with a propeller stirrer, lead to an increase in the permeate flux value of pure water by about 20% for each of the studied membranes. Depending on the concentration of thorium and the pH of the feed solution, retentions between 84.9% and 98.4% were obtained. An important observation was the retention jump at pH 2 for the ABCE–sPEEK composite membrane. In the paper, a thorium ion retention mechanism is proposed for the sPEEK membrane and the ABCE–sPEEK composite membrane. [ABSTRACT FROM AUTHOR]

Recently, research on polyoxometalates (POMs) has gained significant momentum. Owing to their properties as electronic sponges, POMs catalyst harbor substantial potential in lithium‐sulfur battery research. However, POMs undergo a transformation into reduced heteropoly blue (HPB) during electrochemical reactions, which then dissolve into the electrolyte, resulting in catalyst loss. In this research, we amalgamated 18‐crown‐6 (CR6) with K3PW12O40, (KPW), synthesized a novel POM‐based supramolecular compound, and integrated it with graphene oxide (GO) to fabricate a multi‐functional composite polypropylene (PP) separator KPW‐CR6/GO/PP. The crown ether array was employed to immobilize POM and construct ion transport channels, thereby enhancing the Li+ migration rate and capturing polysulfides. Subsequently, leveraging the stable structure and redox properties of POM, the polysulfide is catalyzed to transform and inhibit the shuttle effect, thereby protecting the Li anode. The lithium‐sulfur batteries with the Crown ether‐POM supramolecular compound separators, exhibit enhanced capacity and stability (1073.3 mAh g−1 at 1.0 C, and 81.5 % retention rate after 250 cycles). The battery (S loading: 3.2 mg cm−2) presents an initial specific discharge capacity of 543.4 mAh g−1 at 0.5 C, with 89.8 % of the capacity retained after 160 cycles. This underlines the practical application potential of Crown ether‐POM supramolecular materials in Li−S batteries. [ABSTRACT FROM AUTHOR]

Host‐guest complexation offers a promising approach for mitigating surface defects in perovskite solar cells (PSCs). Crown ethers are the most widely used macrocyclic hosts for complexing perovskite surfaces, yet their supramolecular interactions and functional implications require further understanding. Here we show that the dipole moment of crown ethers serves as an indicator of supramolecular interactions with both perovskites and precursor salts. A larger dipole moment, achieved through the substitution of heteroatoms, correlates with enhanced coordination with lead cations. Perovskite films incorporating aza‐crown ethers as additives exhibited improved morphology, reduced defect densities, and better energy‐level alignment compared to those using native crown ethers. We report power‐conversion efficiencies (PCEs) exceeding 25 % for PSCs, which show enhanced long‐term stability, and a record PCE of 21.5 % for host–guest complexation‐based perovskite solar modules with an active area of 14.0 cm2. [ABSTRACT FROM AUTHOR]

Copyright of Duzce University Journal of Science & Technology is the property of Duzce University Journal of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ZIF‐8 membranes have long been prized for their exceptional C3H6/C3H8 separation performance. On the other hand, ZIF‐8 has structural flexibility, where the external pressure triggers channel expansion, potentially deteriorating the molecular sieving ability. Here, we demonstrate a reliable strategy to fine‐tune the flexible pore structure of ZIF‐8 by embedding crown ether within a ZIF‐8 membrane. Benzo‐15‐crown‐5 (15C5) was selected as the cavity occupant and perfectly confined in the sodalite (SOD) cage of ZIF‐8. The 15C5 molecules, which have a size comparable to the nanocage, impose a spatial constraint on linker rotation, enabling the phase transition to a rigid structure in the flexible ZIF‐8. The corresponding 15C5@ZIF‐8 membranes achieve an ultrahigh C3H6/C3H8 selectivity of 220, outperforming that of most membranes. Unlike their flexible counterparts, the resulting membranes manifest a positive increase in the C3H6/C3H8 separation factor with elevated pressure, securing a record‐high C3H6/C3H8 separation factor of 331 under 7 bar. More importantly, extraordinary separation stability was demonstrated with continuous measurement, which is highly desirable for practical applications. [ABSTRACT FROM AUTHOR]

The practical deployment of rechargeable aqueous zinc‐ion batteries (RAZBs) in the scaled power system suffers from unregulated Zn dendrite growth as well as parasitic reactions at the zinc foil/aqueous electrolyte interface, leading to insufficient zinc utilization and severe electrode corrosion. Herein, a novel crown ether additive is developed, with tailored molecular engineering, to stepwise regulate the Zn2+ solvation network and interfacial chemistry of Zn metal anode. The designed crown ether (C5SeCN), featuring zincophilic cyano group and hydrophobic selenium, efficiently reconstructs the solvation sheath of Zn ions at the 0.3 wt.% dose amount. Additionally, the ozone plasma treatment tethers the O2‐ groups onto the thin‐layer zinc foil, which thus binds Se atoms of the C5SeCN to the Zn anode. The Zn||Zn symmetric cells exhibit a lifespan of over 4500 h at 1 mA cm−2 and high current density endurance of up to 10 mA cm−2. Moreover, the 2 mAh cm−2 Zn||V2O5 full cell model, at the low N/P ratio of 2.8 with a lean electrolyte (E/C ratio = 10 µL mAh−1), enables robust cycling endurance at 2 A g⁻¹ for 300 cycles. This study unravels the interfacial design rationales for maximizing zinc utilization and highlights the commercial potential of crown ether additives for RAZBs development. [ABSTRACT FROM AUTHOR]

A six‐cyclic crown ether‐type pillar[5]arene was synthesized, and the five ethylene oxide loops were located outside the cavity and not affected by temperature changes which was confirmed by variable‐temperature NMR experiment in DMSO‐d6 and CDCl3 and 2D 1H−1H NOESY experiment in CDCl3. The six‐cyclic pillar[5]‐crown also showed greater binding ability of host‐guest with bis(pyridinium) derivatives than conventional alkoxy pillar[5]arenes that illustrated through 1H NMR titration spectroscopic experiment in acetone‐d6/CDCl3 (1 : 1) and UV‐vis titration experiments in CHCl3 at room temperature. The five benzocrown ethers at the periphery were able to bind metal cations by 1H NMR titration spectroscopic experiment in CD2Cl2/methanol‐d4(9 : 1). [ABSTRACT FROM AUTHOR]

Oligoamines in cellular metabolism carry extremely diverse biological functions (i.e., regulating Ca2+-influx, neuronal nitric oxide synthase, membrane potential, Na+, K+-ATPase activity in synaptosomes, etc.). Furthermore, they also act as longevity agents and have a determinative role in autophagy, cell growth, proliferation, and death, while oligoamines dysregulation is a key in a variety of cancers. However, many of their mechanisms of actions have just begun to be understood. In addition to the numerous biosensing methods, only a very few simple small molecule-based tests are available for their selective but reversible tracking or fluorescent labeling. Motivated by this, we present herein a new fluorescent bis(acridino)-crown ether as a sensor molecule for biogenic oligoamines. The sensor molecule can selectively distinguish oligoamines from aliphatic mono- and diamino-analogues, while showing a reversible 1:2 (host:guest) complexation with a stepwise binding process accompanied by a turn-on fluorescence response. Both computational simulations on molecular docking and regression methods on titration experiments were carried out to reveal the oligoamine-recognition properties of the sensor molecule. The new fluorescent chemosensor molecule has a high potential for molecular-level functional studies on the oligoamine systems in cell processes (cellular uptake, transport, progression in cancers, etc.). [ABSTRACT FROM AUTHOR]

Supramolecular adhesives are attracting considerable attentions owing to their dynamic and reversible bonding, while the complex curing conditions and poor performance under extreme conditions severely restrict their applicability. Herein, a series of tetra‐crown ether‐terminated polyethylene glycol (TCE‐PEG) adhesives are presented in which plenty of supramolecular interactions, including Van der Waals, hydrogen bonding, π–π staking, metal coordination, and electrostatic ones, provide strong adhesion on multiple types of substrates. Highly relevant for practical applications, ultra‐strong adhesivity of TCE‐PEG can be achieved without requiring additional ultraviolet radiation, heat, or chemical treatment at ambient temperature. It also exhibits durable adhesive behavior, excellent underwater stability, and low‐temperature tolerance. Especially, by incorporating ionic polymer fragments of polyethyleneimine hydrochloride, additional hydrogen bonding between secondary amines and crown ether rings can be induced to enhance the lap‐shear strength to 7.21 MPa due to the formation of supramolecular cross‐linked network. This work pioneers a rather unique supramolecular approach for easily formed, ultra‐strong crown‐ether‐based adhesives bearing great potential for applications in critical environments of limited heat source and unallowed solvent usage. [ABSTRACT FROM AUTHOR]

Crown ethers (CEs), known for their exceptional host–guest complexation, offer potential as linkers in covalent organic frameworks (COFs) for enhanced performance in catalysis and host–guest binding. However, their highly flexible conformation and low symmetry limit the diversity of CE‐derived COFs. Here, we introduce a novel C3‐symmetrical azacrown ether (ACE) building block, tris(pyrido)[18]crown‐6 (TPy18C6), for COF fabrication (ACE‐COF‐1 and ACE‐COF‐2) via reticular synthesis. This approach enables precise integration of CEs into COFs, enhancing Ni2+ ion immobilization while maintaining crystallinity. The resulting Ni2+‐doped COFs (Ni@ACE‐COF‐1 and Ni@ACE‐COF‐2) exhibit high discharge capacity (up to 1.27 mAh ⋅ cm−2 at 8 mA ⋅ cm−2) and exceptional cycling stability (>1000 cycles) as cathode materials in aqueous alkaline nickel‐zinc batteries. This study serves as an exemplar of the seamless integration of macrocyclic chemistry and reticular chemistry, laying the groundwork for extending the macrocyclic‐synthon driven strategy to a diverse array of COF building blocks, ultimately yielding advanced materials tailored for specific applications. [ABSTRACT FROM AUTHOR]

The effect of crown ethers and polyglycols on the liquid-phase oxidation of cyclohexane and alkylaromatic hydrocarbons (toluene and p-xylene) with molecular oxygen catalyzed by transition metal salts has been investigated. It has been determined that crown ethers increase the reaction rate at both low and high conversion levels of cyclohexane and alkylaromatic hydrocarbons. The additives under study primarily affect the selectivity of the oxidation products. Crown ether and polyglycol additives to cobalt naphthenate increase the cyclohexanone to cyclohexanol molar ratio in cyclohexane oxidation. The crown ether additives to cobalt acetate increase the selectivity for alcohol in the initial stage of toluene and p-xylene oxidation. At higher alkylarene conversion, the additives enhance the selectivity for carboxylic acids. We assume that crown ethers and polyglycols form complexes with transition metal ions, changing the redox potential of the ions. This change in redox potential affects both the reaction rate and the selectivity of the oxidation products. The study concludes that crown ether and polyglycol additives influence the stages of the catalytic liquid-phase oxidation of hydrocarbons. [ABSTRACT FROM AUTHOR]

Abstract Silver ion (Ag+) is of harmful effects to both environment and human health. Ag+ soluble compounds and salts is used in treating mental illness, epilepsy, nicotine addiction, gastroenteritis, and infectious diseases, including syphilis and gonorrhea, and as anti-infective dermatological agent for controlling nose bleeding. However, high Ag+ doses cause several harmful effects to human health such as irreversible pigmentation of skin and eye, and problems to liver and kidney. A bulk membrane Optode is proposed in this work to measure the Ag+ concentration in the pharmaceutical formulations. The membrane optode is prepared from the ionophore 4-nitobenzo-15-crown-5, the ion-exchanger sodium tetrakis (imidazolyl) borate, the plasticizer o-nitrophenyl octyl ether, and the chromoionophore ETH 5294; these components are dissolved in the PVC/THF slurry to form the membrane. The optode is studied by atomic force microscope and UV–visible spectrophotometer, and its spectrum exhibits two maximum wavelengths of 550 and 665 nm, and response for Ag+ at these maximum wavelengths is reproducible in the concentration range of 10–11 to 10–8 M using acetate buffer of pH 5.0, with very low detection limit of 8.8 × 10–12 M. The most important feature in this work is the selectivity improvement for Ag+ over all interfering ions; the selectivity coefficient logarithm $${logK}_{Ag+, cation}^{opt}$$ logK A g + , c a t i o n opt is found to be − 4.3 for Cu2+, − 5.6 for Ni2+ and − 5.0 for Cd2+. The response mechanism is studied by FTIR, and it depends on ion-exchange of Ag+ and sodium imidazolyl borate, followed by the host–guest complexation between Ag+ and the crown ionophore, which is accompanied by concomitant deprotonation of the chromoionphore. The optode has a response time of 2–3 min within lifetime of 10 days with the same response. The optode can be applied successfully for Ag+ determination in the pharmaceutical formulation, PinkEye Relief® eye drop, which is used for treating inflammation, redness and water discharge of the eye; the high recovery and low standard deviation of the results using calibration curve method confirm the accuracy and precision of the proposed optode for its application in real samples.

The thermal stability of dibenzo-21-crown-7 (DB21C7) and its solution in 1,2-dichloroethane (DCE) after contact with nitrogen dioxide, which is a product of nitric acid degradation, was studied. It is shown that exothermic processes accompanied by the release of gaseous products are observed in inert and oxidizing atmosphere. The compounds formed after contact with nitrogen dioxide were determined by gas chromatography–mass spectrometry. Differences in gaseous products in the temperature range of 300℃ were defined for the initial crown ether and for DB21С7 and its solution in DСE after contact with NO2. [ABSTRACT FROM AUTHOR]

Lithium‐oxygen batteries possess an extremely high theoretical energy density, rendering them a prime candidate for next‐generation secondary batteries. However, they still face multiple problems such as huge charge polarization and poor life, which lay a significant gap between laboratory research and commercial applications. In this work, we adopt 15‐crown‐5 ether (C15) as solvent to regulate the generation of discharge products in lithium‐oxygen batteries. The coronal structure endows C15 with strong affinity to Li+, firmly stabilizes the intermediate LiO2 and discharge product Li2O2. Thus, the crystalline Li2O2 is amorphized into easily decomposable amorphous products. The lithium‐oxygen batteries assembled with 0.5 M C15 electrolyte show an increased discharge capacity from 4.0 mAh cm−2 to 5.7 mAh cm−2 and a low charge overpotential of 0.88 V during the whole lifespan at 0.05 mA cm−2. The batteries with 1 M C15 electrolyte can cycle stably for 140 cycles. Furthermore, the amorphous characteristic of Li2O2 product is preserved when matched with redox mediators such as LiI, with the charge polarization further decreasing to 0.74 V over a cycle life of 190 cycles. This provides new possibilities for electrolyte design to promote Li2O2 amorphization and reduce charge overpotential in lithium‐oxygen batteries. [ABSTRACT FROM AUTHOR]

The ion selectivity of 18-crown-6 (18C6) ether has been investigated by DFT method. The following conclusions are drawn with the analyses about the geometrical structure, the binding energy, the natural bond orbital charge population, the infrared spectra, and the spin-spin coupling constant. First of all, the ion selectivity of 18C6 attributes primarily to the valence state, the periodic number, and the volume of the cation. Secondly, for the cation encapsulated complex of the same main group, the variation of distance between two para-oxygen atoms in the complex and in 18C6 (ΔROO) is proportionate to the binding energy of cation and 18C6. Then, the cation, bearing most of the electropositive charges, is encapsulated in the center of six electronegative oxygen atoms. Fourthly, the value of spin-spin coupling constant of cation and peripheral oxygen atom (1J(M, O)) mainly dominated by the Fermi-contact term. The swing of cation along the para-position oxygen atoms is typical and can be taken as a characteristic for ion recognition. [ABSTRACT FROM AUTHOR]

We developed a new approach for the synthesis of flavanone from chalcones without electrical energy, such as stirring or heating, by using a cesium fluoride–crown ether complex. This "zero electrical energy reaction" is a new category of reaction that has the potential to replace the general organic reaction. [ABSTRACT FROM AUTHOR]

Although the flexibility of the quasi−solid polymer electrolyte favors its surface conformal to the electrode, interfacial damage originating from side reactions between the electrolyte and the electrode remains dominant for battery failure. The design of quasi−solid electrolytes compatible with both aggressive nickel−rich cathode and lithium metal anode persists critical to the application of quasi−solid high−voltage lithium metal batteries (LMBs). Herein, a chemical/electrochemical response strategy is proposed to construct simultaneously stable cathodic and anodic interfaces relying on the synergistic effect of 1,4,7,10,13,16−hexaoxacyclooctadecane (18C6) and LiNO3. The distinctive [18C6Li]+NO3− cluster modifies electric double layer structure by specific adsorption on the electrode, thereby regulating the interfacial layer composition and construction. The NO3− on electrode preferentially decomposes to improve the interfacial performances, leaving the [18C6Li]+ to cut off the side reaction. Furthermore, the 18C6 coordinates with detrimental transition metal ions from NMC811 cathode and converts into useful clusters alleviating the knock−on effect. Thus, the quasi−solid electrolyte with 18C6 and LiNO3 enables Li||NMC811 coin cell to cycle stably over wide operation temperature (0−55 °C), especially, achieving high capacity retention of 79.2% after 300 cycles at 30 °C. This chemical/electrochemical response strategy projects new insights into the design of smart reactive electrolytes for high−voltage LMBs. [ABSTRACT FROM AUTHOR]

Our research objective was to investigate the use of 4'-formylbenzo-18-crown-6-ether (4fb18C6) for the covalent labelling of peptides for unambiguous peptide identification. Specifically, 23 peptides were analysed using a coupled system of liquid chromatography and tandem mass spectrometry with electrospray ionization to test de novo sequencing of derivatized and intact peptides. The reaction was optimized for reductive amination to be performed in an aqueous medium at pH 6 using the microwave radiation. After matching the tandem mass spectra of derivatized and intact peptides in the range of ±0.005 Da, the chemical noise was reduced by up to 90 % and six proteins from 17 different species were identified using the BLASTp algorithm (NCBInr and UniProtKB/Swiss-Prot databases). Species identification enabled further accelerated database search using the classical method of mass spectra database matching. The presented method enables reliable de novo sequencing of peptides and represents a new tool for species identification. [ABSTRACT FROM AUTHOR]

Copyright of Inorganic Chemicals Industry is the property of Editorial Office of Inorganic Chemicals Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Loops are prevalent topological structures in cross‐linked polymer networks, resulting from the folding of polymer chains back onto themselves. Traditionally, they have been considered as defects that compromise the mechanical properties of the network, leading to extensive efforts in synthesis to prevent their formation. In this study, we introduce the inclusion of cyclic dibenzo‐24‐crown‐8 (DB24C8) moieties within the polymer network strands to form CCNs, and surprisingly, these loops enhance the mechanical performances of the network, leading to tough elastomers. The toughening effect can be attributed to the unique cyclic structure of DB24C8. The relatively small size and the presence of rigid phenyl rings provide the loops with relatively stable conformations, allowing for substantial energy dissipation upon the application of force. Furthermore, the DB24C8 rings possess a broad range of potential conformations, imparting the materials with exceptional elasticity. The synergistic combination of these two features effectively toughens the materials, resulting in a remarkable 66‐fold increase in toughness compared to the control sample of covalent networks. Moreover, the mechanical properties, particularly the recovery performance of the network, can be effectively tuned by introducing guests to bind with DB24C8, such as potassium ions and secondary ammonium salts. [ABSTRACT FROM AUTHOR]

A new 12-crown 4-ether, 2-nonyl-1,4,7,10-tetraoxacyclododecane (1) was isolated from the leaves of Mahonia fortunei (Berberidaceae). The structure of the new crown ether was elucidated by chemical and physical evidences. [ABSTRACT FROM AUTHOR]