Ether Oxygen Research Articles

The influence mechanism of lignite thermal upgrading on moisture re-adsorption

The influence mechanism of lignite thermal upgrading on moisture re-adsorption was investigated using analytical techniques such as differential thermal analysis–thermogravimetry, Fourier transform infrared spectroscopy and scanning electron microscopy. The results showed that the moisture content of lignite decreased from 44.78 to 25.07% through the drying process. After the moisture in the lignite and the air had reached a dynamic equilibrium, the moisture content of the lignite was 25.75 wt.%. The characteristic functional groups of lignite include hydroxyl, methylene, methyl, carbonyl, carboxyl and ether oxygen. The adsorption distances of the five adsorption sites of carboxyl, phenolic hydroxyl, alcoholic hydroxyl, carbonyl and ether bond to water molecules were 2.081, 2.933, 1.905, 1.860 and 1.881 Å, respectively. The order of the adsorption strength of water molecules on the characteristic functional groups was carbonyl > phenolic hydroxyl > ether oxygen > alcoholic hydroxyl > carboxyl. During the upgrading by drying process, the characteristic functional groups that were prone to hydrogen bonds of water molecules partially decomposed. The reduction of pores and the partial decomposition of hydrophilic functional groups after upgrading in the lignite structure weakened the adsorption capacity of lignite to water molecules. Therefore, the re-absorption of water molecules by lignite was reduced.

Anion-directed structural diversification in four new Cd(II) compounds of a flexible polyether-based dicarboxylic acid

• With a less explored linker 3,6,9-trioxaundecanedioic acid (H 2 toua) a series of complexes with Cd(II) salts containing different counter anions (Cl - , ClO 4 - , OAc - , and NO 3 - ) were synthesized. • A discrete neutral compound [Cd(H 2 toua)Cl 2 ] . H 2 O ( 1 ) is obtained with Cl - whereas a 1D polymeric chain {[Cd(Htoua)(H 2 O)](ClO 4 )} n ( 2 ) is obtained with ClO 4 - counter anion. • Different morphologies are observed with different counter anion analyzed by SEM technique. • Their thermal behavior, Hirshfeld Surface analysis and luminescent properties were also investigated. In this work, we report the chemistry of an unexplored flexible polyether based dicarboxylic acid (3,6,9-trioxaundecanedioic acid, H 2 toua) with four different cadmium salts. With CdCl 2 . H 2 O or Cd(ClO 4 ) 2 . H 2 O in a 1:1 ratio, it remarkably forms a discrete compound [Cd(H 2 toua)Cl 2 ] . H 2 O ( 1 ) and a polymeric ionic compound, {[Cd(Htoua)(H 2 O)](ClO 4 )} n ( 2 ), respectively, as determined by the single crystal X-ray diffraction. In both cases, for the heptacoordinated Cd(II) all basal donor atoms are from the ligand (three ether oxygen and two oxygen atoms from the fully intact or mono-deprotonated carboxylic acid groups, respectively) but with a major difference in axial (trans to each other) coordinated atom types - two chlorines in 1 while one water molecule and a bridging carboxylate oxygen in 2 . Unlike 1 , the carboxylate group of Htoua bridges between the Cd(II) centers for the formation of a 1D polymeric chain in 2 . Furthermore, Hirshfeld surface analysis of the various intermolecular interactions enables quantifiable contributions to crystal packing, revealing the key differences in the interactions encountered by 1 and 2 . Using Cd(OAc) 2 . 6H 2 O as the metal salt, it is possible to make [Cd(toua)] . H 2 O ( 3 ), due to the formation of easily removable volatile acetic acid by-product. On the other hand, a nitrate analogue of 2 , i.e., {[Cd(Htoua)(H 2 O)](NO 3 )} n ( 4 ) is isolated if Cd(NO 3 ) 2 . 4H 2 O is used. All these compounds were characterized by a number of spectroscopic and microscopic methods. Their thermal behaviour and luminescence properties were also determined.

Open-Cage Fullerene as Molecular Container for F- , Cl- , Br- and I.

A 19-membered open-cage fullerene derivative was prepared from C60 in 7 steps and 5.5 % yield through the peroxide-mediate pathway. There are four carbonyl groups, an ether oxygen and a quinoxaline moiety on the rim of the orifice. A chloride anion could be inserted into its cavity by heating with hydrochloric acid at 60 °C for 4 h. Encapsulation of fluoride, bromide and iodide anions was also achieved at slightly more forcing conditions, 90 °C for 14 h. Single crystal X-ray structures of the sodium salt of the chloride and the bromide encapsulated derivatives were obtained, which showed the halide anion in the center of the cavity and two sodium cations connecting two cages through coordination to the oxygen atoms on the rim of the orifices. The halide encapsulation ratio is quantitative in the isolated products.

Open‐Cage Fullerene as Molecular Container for F−, Cl−, Br− and I−

AbstractA 19‐membered open‐cage fullerene derivative was prepared from C60 in 7 steps and 5.5 % yield through the peroxide‐mediate pathway. There are four carbonyl groups, an ether oxygen and a quinoxaline moiety on the rim of the orifice. A chloride anion could be inserted into its cavity by heating with hydrochloric acid at 60 °C for 4 h. Encapsulation of fluoride, bromide and iodide anions was also achieved at slightly more forcing conditions, 90 °C for 14 h. Single crystal X‐ray structures of the sodium salt of the chloride and the bromide encapsulated derivatives were obtained, which showed the halide anion in the center of the cavity and two sodium cations connecting two cages through coordination to the oxygen atoms on the rim of the orifices. The halide encapsulation ratio is quantitative in the isolated products.

A comparative study of Mannosylerythritol lipids (MELs) surfactant adsorption upon the Al12N12 and B12N12 nano-cages as potential candidates for detecting MELs

Aluminum nitride and boron nitride nanocages have recently been discovered. The properties of these compounds vary according to their size. In this paper, we study the adsorption of MELs on aluminum nitride and boron nitride nanocages in the solution phase using density functional theory. The results of adsorption energies indicate that during the adsorption on aluminum nanocages, ether oxygen atoms show stronger adsorption, while adsorption is stronger on boron nitride nanocage from the hydroxyl group oxygen. The results of thermodynamic calculations indicate that all adsorption positions of aluminum nitride are thermodynamically favorable. However, in the case of boron nitride, some positions are thermodynamically unfavorable. In terms of recovery time, borne nitride is not a good adsorbent because of very small recovery time. The aluminum nitride may be able to behave as a suitable sensor for the MELs in the solution phase. Nevertheless, boron nitride does not have this capability, since it does not significantly change the number of conducting electrons.

Oxygen ether chain containing covalent organic frameworks as efficient fluorescence-enhanced probe for water detection

Three covalent organic frameworks (COFs) named as TPPA-DTM-COF, TPPA-BMTP-COF and TPPA-BETP-COF with different lengths of oxygen ether chains were successfully synthesized by the condensation between 4,4′,4''-(1,3,5-triazine-2,4,6-triyl)trianiline (TPPA) with 2,5-dimethoxyterephthalaldehyde (DTM), 2,5-bis(2-methoxyethoxy)terephthalaldehyde (BMTP) and 2,5-bis(2-(2-methoxyethoxy)ethoxy)terephthalaldehyde (BETP), respectively, which have high crystallinity, large specific surface area and high thermochemical stability. The fluorescence performance of the as-prepared COFs in acetonitrile showed that the longer the oxygen ether chain, the stronger the fluorescence intensity, this may be related to the inhibition of aggregation-caused quenching (ACQ) effect with the increase of interlayer spacing. The resulting COFs also exhibited different emission in different solvents, and their fluorescence intensity has a significant and rapid response to water in organic solvents. Among them, TPPA-DTM-COF shows the most stable fluorescence emission and good dispersion in organic solvents. Its fluorescence intensity is linear with water content in acetonitrile ranging from 0% to 15% (V/V), and the detection limit was calculated to be 0.27%. In addition, the detection limits of COF in ethanol, THF and DMF are 0.15%, 0.43% and 0.39%, respectively. The mechanism of TPPA-DTM-COF detect water with fluorescence “on” may be that the water can form hydrogen bonds with N and O atoms on the skeleton of TPPA-DTM-COF, which enhanced the stability of the excited states of the COFs, thereby enhancing the intramolecular charge transfer (ICT) in the excitation state, leading to the enhancement of fluorescence. The superior properties of TPPA-DTM-COF inducing the as-prepared COF has a great prospect for trace amount water detection in organic solvents in the form of fluorescence enhancement.

Multiblock copolymers containing polyether segments for separation of C4 hydrocarbons

Separation of C4 paraffins and C4 olefins from each other is an underdeveloped sector of membrane gas separation. Permeabilitieis, diffusivities and solubilities of C4 paraffins (i.e. n-butane and isobutane) and C4 olefins (i.e. cis-2-butene, trans 2-butene, 1-butene, isobutylene and 1,3-butadiene) in three commercial polymers- PEBAX 2533, PolyActive1500PEGT77PBT23 and PolyActive4000PEGT77PBT23 are reported in this study for the first time. The aim of this study is to thoroughly understand the single gas permeation mechanism of the C4 paraffins and C4 olefins through the multiblock copolymers. The cohesive energy density of the polyether segments plays a vital role to determine the permeabilities through the polymer. The selectivity of the olefin/paraffin gas pairs are largely dependent on the content of the ether oxygen of the polyether segments. But the selectivity of the paraffin gas pair and the olefin isomer gas pairs are not influenced by the ether oxygen content of the polyether segments of the multiblock copolymers.

Pyrolytic stage evolution mechanism of Zhundong coal based on reaction consistency analysis of mono/multi molecular models

Zhundong coalfield is the largest coalfield in China and the unclear stage evolution mechanism of Zhundong coal pyrolysis is the key factor restricting its coal fire control. Here, the monomolecular model (299 atoms) and large-scale multimolecular model (5083 atoms) were constructed for Liu huanggou (LHG) coal from Zhundong coalfield. The pyrolysis processes of the two models were calculated by ReaxFF MD method. Based on the reaction consistency analysis, the reaction paths tracing on pyrolysis stage evolution and toxic gases formation mechanisms were obtained. The LHG coal pyrolysis process is mainly because of the breakages of the ether oxygen bridge bonds, thioether bridge bonds and aliphatic hydrocarbon bridge bonds. It begins with the shedding of small molecules and then undergoes the thermal decomposition of the main structure and pyrolytic fragments. During the pyrolysis process, the LHG coal has constantly broken out tars, gases and other key products, accompanied by a large number of free radicals and intermediates produced. The main sources of CO are the active reaction sites where the carbonyl group and the carboxyl group located; H2S is directly produced from the sulfhydryl group. The research results will guide the staged control and directional transformation of coal fire.

A high-safety electrolyte based on functionalized ionic liquid and polyurethane for lithium batteries

Developing high-safety electrolytes is very important to improve the safety and operative temperature of lithium batteries. In this study, a heat-resistant and non-flammable electrolyte is constructed by introducing a functionalized ionic liquid N-methyl-N-methoxyethyl-pyrrolidinium bis(fluorosulfonyl)imide (Pyr12O1FSI, IL1) into porous polyurethane (PU) matrix. IL1 contains ether functional group, which can increase the chain flexibility of IL and provide more ion migration channels. Moreover, IL1 shows high compatibility with PU matrix because the intermolecular hydrogen bond is formed by NH groups of PU and ether oxygen of IL1, which is evidenced by Fourier transform infrared spectroscopy (FTIR) tests and density functional theory (DFT) calculations. The binding energy further corroborates the enhanced intermolecular interaction between IL1 and PU. Owing to the superior characteristics of IL1 and synergetic coupling with PU, PU-IL1 electrolyte exhibits good electrochemical performance and endows LiFePO4/Li (LFP/Li) battery with a high specific capacity of 135 mA h g−1 and 99% capacity retention after 100 cycles at 0.2C, 30 °C. In addition, the LFP/Li battery with PU-IL1 electrolyte exhibits a high capacity of 134 mA h g−1 (0.5C) and it remains 98% after 100 cycles at a high temperature of 80 °C.

Enabling Aromatic Hydroxylation in a Cytochrome P450 Monooxygenase Enzyme through Protein Engineering.

The cytochrome P450 (CYP) family of heme monooxygenases catalyse the selective oxidation of C-H bonds under ambient conditions. The CYP199A4 enzyme from Rhodopseudomonas palustris catalyses aliphatic oxidation of 4-cyclohexylbenzoic acid but not the aromatic oxidation of 4-phenylbenzoic acid, due to the distinct mechanisms of aliphatic and aromatic oxidation. The aromatic substrates 4-benzyl-, 4-phenoxy- and 4-benzoyl-benzoic acid and methoxy-substituted phenylbenzoic acids were assessed to see if they could achieve an orientation more amenable to aromatic oxidation. CYP199A4 could catalyse the efficient benzylic oxidation of 4-benzylbenzoic acid. The methoxy-substituted phenylbenzoic acids were oxidatively demethylated with low activity. However, no aromatic oxidation was observed with any of these substrates. Crystal structures of CYP199A4 with 4-(3'-methoxyphenyl)benzoic acid demonstrated that the substrate binding mode was like that of 4-phenylbenzoic acid. 4-Phenoxy- and 4-benzoyl-benzoic acid bound with the ether or ketone oxygen atom hydrogen-bonded to the heme aqua ligand. We also investigated whether the substitution of phenylalanine residues in the active site could permit aromatic hydroxylation. Mutagenesis of the F298 residue to a valine did not significantly alter the substrate binding position or enable the aromatic oxidation of 4-phenylbenzoic acid; however the F182L mutant was able to catalyse 4-phenylbenzoic acid oxidation generating 2'-hydroxy-, 3'-hydroxy- and 4'-hydroxy metabolites in a 83 : 9 : 8 ratio, respectively. Molecular dynamics simulations, in which the distance and angle of attack were considered, demonstrated that in the F182L variant, in contrast to the wild-type enzyme, the phenyl ring of 4-phenylbenzoic acid attained a productive geometry for aromatic oxidation to occur.

Structure and free volume of fluorine-containing polyetherimides with pendant di-tert-butyl groups investigated by molecular dynamics simulation

The study is focused on the investigation of structural properties of 5 polyetherimides (PEIs) containing 1,4-bis-[{2′-trifluoromethyl 4′-(4″-aminophenyl)phenoxy}]-2,5-di-tert-butylbenzene diamine monomer (FMTBDA) and 5 different dianhydride monomers (PMDA, BTDA, ODPA, 6FDA, and BPADA) using molecular dynamics simulations. 32 independent models were built for each polymer. Densities calculated for the modeled samples were compared with the experimental ones, giving difference of up to 6%. Accessible free volume (AFV) distribution was evaluated for the investigated polymers. It was shown that AFV for all the probe sizes decreased in a row: PMDA > BTDA∼6FDA > ODPA > BPADA, which is in line with the experimental gas transport parameters shown previously. Bimodal AFV distribution was demonstrated. Specific surface area (SSA) was calculated for the models of polymers, and fragments composing the inner surface of the free volume were determined. Analysis of the elements of the free volume surface has shown that sp 3 carbon (С sp3 ), carbonyl oxygen (O C=O ), and fluorine (F) atoms tend to form free volume elements, while imide nitrogen (N imide ) and ether oxygen (O ether ) tend to compose polymer bulk. • Accessible cavities distribution shows bimodal behavior for FMTBDA PEIs. • C Sp3 , carbonyl oxygen and fluorine atoms tend to form free volume elements. • Imide nitrogen and ether oxygen tend to compose FMTBDA PEIs polymer bulk. • ∼50% of H 2 AFV in FMTBDA PEIs is also accessible to molecules larger than O 2 .

Lithium ion capacitor based on polyoxide-polythiol co-networks

The present article emerges from our recent finding of supercapacitive behavior of polymer electrolyte membranes (PEM) via photo-crosslinking of polyethylene glycol diacrylate (PEGDA) with trimethylolpropane tris(3-mercaptopropionate) (TMPTMP) via thiol-ene click reaction in the presence of succinonitrile (SCN) plasticizer and lithium bis(trifluoromethane sulfonyl imide) (LiTFSI) salt. The photo-cured polymer electrolyte membrane (PEM) co-network revealed a superionic conductor level of 1.26 mS/cm at 23 °C and an elongation at break of around 23%, suggestive of a highly conductive and stretchable character. Upon deep discharging to the potential range of lithium metal anode at −0.5–0.5 V, lithium-ion stripping from the Li metal electrode (i.e, oxidation at 0–0.3 V) affords continuous supply of Li-ions, which not only afford the lithium-ion storage within the PEM through ion-dipole interaction (i.e., temporary holding of Li ions), but also facile ion transport once the complexation sites of Li-ion with ether oxygen and thiols are fully saturated with excess Li-ions. To elucidate a plausible energy storing mechanism of the PEM, the cyclic voltammetry (CV) investigation was performed in the full battery configuration as well as in the symmetric carbonaceous electrode configuration. A novel supercapacitor behavior was noticed in the PEM involving both pseudocapacitor and electric double-layer capacitor (EDLC) types. Last but not least, specific capacitance and specific energy densities from the CV curves were evaluated and discussed.

Piezo-Responsive Hydrogen-Bonded Frameworks Based on Vanillin-Barbiturate Conjugates.

A concept of piezo-responsive hydrogen-bonded π-π-stacked organic frameworks made from Knoevenagel-condensed vanillin–barbiturate conjugates was proposed. Replacement of the substituent at the ether oxygen atom of the vanillin moiety from methyl (compound 3a) to ethyl (compound 3b) changed the appearance of the products from rigid rods to porous structures according to optical microscopy and scanning electron microscopy (SEM), and led to a decrease in the degree of crystallinity of corresponding powders according to X-ray diffractometry (XRD). Quantum chemical calculations of possible dimer models of vanillin–barbiturate conjugates using density functional theory (DFT) revealed that π-π stacking between aryl rings of the vanillin moiety stabilized the dimer to a greater extent than hydrogen bonding between carbonyl oxygen atoms and amide hydrogen atoms. According to piezoresponse force microscopy (PFM), there was a notable decrease in the vertical piezo-coefficient upon transition from rigid rods of compound 3a to irregular-shaped aggregates of compound 3b (average values of d33 coefficient corresponded to 2.74 ± 0.54 pm/V and 0.57 ± 0.11 pm/V), which is comparable to that of lithium niobate (d33 coefficient was 7 pm/V).

Correlation of electrical, thermal, and crystal parameters of complex composite films based on polyethylene oxide (PEO) doped by copper sulfate (CuSO4)

Ionic conductivity and the conductivity mapping of PEO/CuSO4 complex composite films are investigated to show the effect of the complexation of the Cu+2 and SO4−2 ions on the PEO matrix. Adding CuSO4 into the PEO matrix decreases the crystallinity degree of PEO films and consequently enhances the ionic conductivity and charge diffusion due to increasing the segmental motion of PEO. The FTIR spectra demonstrate the complexation of the Cu+2 ions to the ether oxygen in PEO films, while the SO4−2 ions behave as free ions in the polymer matrix as elucidated in the vibrational modes of PEO/CuSO4 thin films. Introducing CuSO4 into the PEO matrix improves the thermal stability of the complex composite films. Moreover, the conductivity of the pure PEO film is 1.67 × 10−4 S/cm at room temperature. Increasing CuSO4 concentration in the PEO films to 20% increases the ionic conductivity up to 6.13 × 10−4 S/cm.

Adsorption process and mechanisms of AEO-3/dodecane mixed collector on low-rank coal surface driven by water flow: A non-equilibrium molecular dynamics simulation study

During coal slime flotation, the collector is adsorbed to the coal in the form of fine oil droplets in the turbulent slurry. And understanding the adsorption behavior of collector oil droplets on the coal surface is important for the development of efficient collector. In this study, the adsorption process and mechanism of triethylene glycol dodecyl ether (AEO-311triethylene glycol dodecyl ether.)/dodecane mixed collector oil droplet (MCOD22mixed collector oil droplet.) on the surface of low-rank coal driven by water flow were investigated by non-equilibrium molecular dynamics simulations. The changes of the mass center velocity of MCOD, contact area and interaction energy between MCOD and coal during the simulation were analyzed, and the adsorption process was divided into the adhesion stage, spreading stage and equilibrium stage. The kinetic reason for the adsorption of AEO-3 molecules at the interface was found. The pushing of oil droplet by the water flow caused the AEO-3 molecules to be slowly pressed into the contact interface between the oil droplet and coal, and the adsorption occurred. The presence of polar oxygen-containing functional groups on the AEO-3 molecule makes it much more strongly adsorbed on low-rank coal than dodecane. Water molecules play an important role in the adsorption process of AEO-3 with coal, and the bridging action of water molecules that enables indirect adsorption of collector with coal was proposed. The water molecule connects AEO-3 and coal molecules, which cannot form hydrogen bond due to the distance, through hydrogen bonding, and inserts between alcohol oxygen, ether oxygen and carbonyl oxygen, which are originally mutually exclusive, so that the three of them (OAEO-3, H2O and Ocoal) are connected together through hydrogen bonding (OAEO-3…H-O-H…Ocoal), and the stability of AEO-3 adsorption on coal surface is greatly enhanced. The presence of strong indirect electrostatic interactions between polar collector and coal generated by the bridging action of water molecules proves that it is the strong electrostatic interactions that are the reason for the strong flotation performance of polar collector on low-rank/oxidized coals.

Theoretical Study of the Electrochemical Properties for Solid Electrolytes Containing Ethoxy and Carbonate Groups

The density functional theory calculations are performed to investigate the redox properties of dual functional groups polymer (polycarbonate possessing ethoxy side groups (PEtGEC), poly(diethylene glycol carbonate) (PDEC), poly(triethylene glycol carbonate) (PTEC)) electrolytes containing carbonate and ethoxy groups, and coordination structures and interactions of Li+ ions with polymers. The oxidation and reduction processes of dual functional groups polymers occur on the ethoxy and carbonate groups, respectively. The electrochemical windows of PEtGEC (4.08 V) and PDEC (4.42 V) electrolytes are predicted by calculations. The oxidation potentials of electrolytes are defined by the polymers, and the electrolytes without branched chains have better oxidation stability. The reduction potentials are controlled by the salt anion, and the structure of lithium salt changes during the reduction process. The simulated infrared spectra show that Li+ ions interact with the carbonyl and ether oxygen atoms of polymers. The number of oxygen atoms that coordinate with the Li+ ion in these electrolytes is 4–5. The PEtGEC electrolyte has favorable transport ability due to its loose coordination environment and easy formation, the transformation between configurations, the dual-path of Li+ ions transport and good long range transport ability. These findings provide theoretical guidance for designing solid electrolytes in the future.

Effect of demineralization on Yimin lignite by experiments and molecular simulation techniques

The structural changes of Yimin lignite after demineralization treatment were characterized by ultimate analysis, X–ray diffraction (XRD), 13C nuclear magnetic resonance (13C NMR) and X–ray photoelectron spectroscopy (XPS) in this study. The results showed that the number of carboxylic acid, phenolic hydroxyl and ether oxygen increased after demineralization treatment, while the number of aliphatic rings decreased and the length of aliphatic chain shortened. Based on the structural parameters, the single molecular models of raw coal and demineralized coal were constructed. In order to further analyze the changes in the three–dimensional configuration and potential energy of the large–scale molecular models before and after demineralization treatment, the periodic unit cells containing five single molecular models for raw and demineralized coal were constructed and evaluated by molecular simulation techniques. The results showed that the demineralization treatment affected the stability of the cross–linked structure of Yimin lignite molecules. The demineralization treatment has a greater impact on the electrostatic energy (EE) and the bond inversion energy (EI). For single molecules, Mulliken population analysis and frontier molecular orbital analysis results showed that the chemical reactivity of Yimin lignite molecules in nucleophilic and electrophilic reactions was weakened after demineralization treatment.

Novel analgesic/anti-inflammatory agents: 1,5-Diarylpyrrole nitrooxyethyl sulfides and related compounds as Cyclooxygenase-2 inhibitors containing a nitric oxide donor moiety endowed with vasorelaxant properties

The design of compounds able to combine the selective inhibition of cyclooxygenase-2 (COX-2) with the release of nitric oxide (NO) is a promising strategy to achieve potent anti-inflammatory agents endowed with an overall safer profile and reduced toxicity upon gastrointestinal and cardiovascular systems. With the aim of generating novel and selective COX-2 inhibiting NO-donors (CINOD) and encouraged by the promising results obtained with our nitrooxy- and hydroxyethyl ethers 11 and 12 reported in previous works, we shifted our attention on the synthesis of isosteric thioanalogs nitrooxy- and hydroxy ethyl sulfides 13a-c and 14a-c, respectively, along with their oxidation products nitrooxy- and hydroxyethyl sulfoxides 15a-c and 16a-c, respectively, also referred to as thio-CINOD. Preliminary data and metabolic analysis highlighted how the isosteric substitution of the ethereal oxygen atom of 11a-c with sulfur in compounds 13a-c, independently from the presence and the number of fluorine atoms in N1-phenyl ring, leads to new selective and highly potent COX-2 inhibitors, capable to induce vasorelaxant responses in vivo. The same behavior is observed with their oxidized counterparts nitrooxyethyl sulfoxides 15a-c, in which the oxidation state of the sulfur atom and the presence of the additional oxygen atom play a substantial role in enhancing compounds activity and vasorelaxation. In addition, the screened compounds proved significantly efficacious in mouse models of inflammation and nociception at the dose of 20 mg/kg.

Multiple ionic conduction highways and good interfacial stability of ionic liquid-encapsulated cross-linked polymer electrolytes for lithium metal batteries

PEO-based electrolytes are promising for solid-state lithium metal batteries, but their low ionic conductivity and unstable interfacial compatibility with electrodes are the bottlenecks restricting their further applications. Herein, a unique ionic liquid (Pyr14TFSI)-encapsulated cross-linked polymer electrolyte with abundant ether–oxygen repeat units (C-SPE-IL) is proposed and prepared through an in-situ thermal polymerization process. The Pyr14+ cations of ionic liquid present a stronger affinity towards ether–oxygen groups by means of tight coordinated interactions, which promotes ionic liquid encapsulated uniformly in the polymer matrix to release more mobile Li ions into ionic liquid and create multiple ionic conduction highways in both ionic liquid and polymer matrix. The C-SPE-IL shows a much higher ionic conductivity of 3.98 × 10−4 S/cm at 30 °C. Moreover, tight interfaces with LiF– and Li3N– rich components between C-SPE-IL and Li anode are constructed to ensure effective suppression of lithium dendrites during cycling. The LiFePO4/Li batteries using C-SPE-IL present stable cycling performances at both 35 °C and 60 °C. This work provides a facile and accessible approach to design novel SPE with both ionic conduction highways and good interfacial stability for high-performance solid-state lithium metal batteries.

Effect of Alkyl Side Chain Length on the Lithium-Ion Conductivity for Polyether Electrolytes.

The design guidelines of polymer structure to effectively promote lithium-ion conduction within the polymer electrolytes (PEs) are crucial for its practical use. In this study, the electrolyte properties of a simple polyether having alkyl side chains with varied lengths (−(CH2)m−H, m = 1, 2, 4, 6, 8, and 12) were compared and established a valid design strategy based on the properties of the alkyl side chain. Various spectro-electrochemical measurements successfully connected the electrolyte properties and the alkyl side chain length. Steric hindrance of the alkyl side chain effectively suppressed the interaction between ether oxygen and lithium-ion (m ≥ 2), decreasing the glass transition temperature and the activation energy of lithium-ion transfer at the electrode-electrolyte interface. The strong hydrophobic interactions aligned and/or aggregated the extended alkyl group (m ≥ 8), creating a rapid lithium-ion transport pathway and enhancing lithium-ion conductivity. A clear trend was observed for the following three crucial factors determining bulk lithium-ion transport properties along with the extension of the alkyl side chain: 1) salt dissociability decreased due to the non-polarity of the alkyl side chain, 2) segmental mobility of polymer chains increased due to the internal plasticizing effect, and 3) lithium-ion transference number increased due to the inhibition of the bulky anion transport by its steric hindrance. The highest lithium-ion conductivity was confirmed for the PEs with an alkyl side chain of moderate length (m = 4) at 70°C, indicating the optimized balance between salt dissociability, polymer segmental mobility, and selective lithium-ion transfer. The length of an alkyl side chain can thus be a critical factor in improving the performance of PEs, including thermal stability and lithium-ion conductivity. Precise tuning of the alkyl side chain-related parameters such as steric hindrance, polarity, internal plasticizing effect, and self-alignment optimizes the polymer segmental mobility and salt dissociability, which is crucial for realizing high lithium-ion conductivity for PEs.