Ring Skeleton Research Articles

Self-repaired cathode electrolyte interphase to stabilize the high-nickel cathode interface by a sustained-release multifunctional electrolyte additive

Increasing the nickel content in high-nickel LiNixCoyMn1-x-yO2 cathode materials (NCM) can boost their energy density. However, the consequence of rising Ni content in NCM consists in the heightened stress buildup, intensified irreversible phase transition and severe electrolyte decomposition, and consequently accelerating the battery’s degradation. In the current study, we have revealed that the 4-fluoro-N, N dimethylbenzenesulfonamide (FBSN) as an electrolyte additive can refrain the typical dehydrogenation of EC. Furthermore, a continuously repaired cathode electrolyte interphase (CEI) is designed elaborately on LiNi0.9Co0.05Mn0.05O2 (NCM90) surface by employing the FBSN as a sustained-release electrolyte additive to enhance cycling stability of NCM90||Li cells. This CEI, composed of high mechanical strength LiF and benzene ring skeleton, along with conductive Li+ moieties (S-rich and N-rich species), can be effectively self-repaired in time when damaged, reduce the interaction between the NCM90 and sensitive electrolyte, and mitigate the devastation to the NCM90 cathode surface. As a result, the NCM90||Li cells with 2 % FBSN-containing electrolyte delivers a capacity retention of 90.2 % after 200 cycles at 1C, and 83.1 % after 200 cycles even at higher voltage of 4.5 V, superior than that of Base electrolyte (70.0 % at 4.3 V and 68.0 % at 4.5 V). This study provides an engaging approach to design electrolytes for high-nickel cathodes by autonomously interfacial repair.

Reductive Oxy-Nazarov Cyclization toward Expedient Construction of a Cyclopenta[1,2-b]pyrrolo[1,2-a]azepine Ring System: Formal Total Syntheses of Stemonamine and Cephalotaxine.

Formal total syntheses of stemonamine and cephalotaxine bearing the core cyclopenta[1,2-b]pyrrolo[1,2-a]azepine ring skeleton were achieved. The general synthetic strategy in the synthesis features the reductive oxy-Nazarov cyclization as key step, leading to the versatile construction of N-substituted spiro quaternary stereogenic centers from readily available starting materials.

Simultaneous SERS Sensing of Cysteine and Homocysteine in Blood Based on the CBT-Cys Click Reaction: Toward Precisive Diagnosis of Schizophrenia.

At present, there is a lack of sufficiently specific laboratory diagnostic indicators for schizophrenia. Serum homocysteine (Hcy) levels have been found to be related to schizophrenia. Cysteine (Cys) is a demethylation product in the metabolism of Hcy, and they always coexist with highly similar structures in vivo. There are few reports on the use of Cys as a diagnostic biomarker for schizophrenia in collaboration with Hcy, mainly because the rapid, economical, accurate, and high-throughput simultaneous detection of Cys and Hcy in serum is highly challenging. Herein, a click reaction-based surface-enhanced Raman spectroscopy (SERS) sensor was developed for simultaneous and selective detection of Cys and Hcy. Through the efficient and specific CBT-Cys click reaction between the probe containing cyan benzothiazole and Cys/Hcy, the tiny methylene difference between the molecular structures of Cys and Hcy was converted into the difference between the ring skeletons of the corresponding products that could be identified by plasmonic silver nanoparticle enhanced molecular fingerprint spectroscopy to realize discriminative detection. Furthermore, the SERS sensor was successfully applied to the detection in related patient serum samples, and it was found that the combined analysis of Cys and Hcy can improve the diagnostic accuracy of schizophrenia compared to a single indicator.

Multi-responsive novel phosphamide organogels dominated by a natural diterpene rigid backbone

Functional supramolecular organogels with unique properties and morphology can be obtained by designing gelators’s chemical structure. Rosin, an important natural renewable diterpene resource, consists of a rigid ring skeleton and chiral structure similar to triterpenoids and has excellent self-assembly ability in solution. In this paper, four novel rosin-based derivatives were proposed and synthesized in one step by introducing phosphamide groups by using natural rosin as raw material. They could form eleven types of monoamide and diamide organogels in specific solvents. The minimum gelatinization concentration is 50–180 mg/mL. In particular, by adjusting the number and type of phosphamide groups and rigid structures, the morphology and other properties of the gel could be modulated. Two-dimension lamellar and three-dimensional fiber network organogels were obtained and the hydrogen bond and π–π stack were proved to be the most important driving forces for the gelation. What is particularly important is that the gels exhibited multiple stimulus responsiveness, such as temperature, acid-base and anions. Thus, the four dehydroabietylamine phosphamide gelators synthesized by the one-step method provide new ways of designing novel gel-based soft materials for intelligent response, ion detection, etc.

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Oxyallyl cations, as powerful electrophilic intermediates, have shown versatile utilities in organic synthesis. Modular synthesis of multi‐substituted cyclobutanones enabled by oxyallyl cations provides facile access to multi‐substituted cyclobutanones via direct nucleophilic substitution of (di)chlorocyclobutanones under mild basic conditions. Both aryl or alkyl substituents could be efficiently introduced on the four‐membered ring skeleton. Further transformation leads to tetrasubstituted cyclobutane derivatives in a stereoselective manner, demonstrating potential synthetic utility. More details are discussed in the article by Lu et al. on page 459—463.image

Current Distortion and Sensitivity Calibration Problems of Rogowski Coil

Driven by technology, China's power system has been greatly improved, and has been gradually transformed and upgraded, bringing great improvements to performance in all aspects. Current distortion and sensitivity misalignment of Rogowski coils have always been the key problems to be solved in practical applications. This paper summarizes the methods of calibrating the sensitivity of the Rogowski coil in the shape of the single ring arbitrary skeleton, the Rogowski coil of the double ring skeleton and the Rogowski coil in the shape of the round skeleton, which provides the basis for other improvements of the Rogowski coils. The existing method to solve the current distortion of the Rogowski coil has a single method in the output of the differential current signal, which will reduce the limitation of the measurement range, and the suppression problem still cannot be solved well. This paper summarizes the solutions to current distortion in Rogowski coils, introduces the causes and solutions of current sensor and transistor current distortion, and puts forward certain correlations to provide reference and direction for follow-up research.

Herpotriquinones A and B, Two Dimeric Naphthoquinone-Epoxycyclohexenone Adducts with Anti-Neuroinflammatory Activity from the Isopod-Associated Fungus Herpotrichia sp. SF09

Herpotriquinones A and B (1 and 2), two pyran-bridged naphthoquinone-epoxycyclohexenone dimers with an unprecedented 6/6/6/6/6-fused pentacyclic ring skeleton, along with two known precursors (3 and 4) were isolated from the...

Rongalite/iodine-mediated C(sp3)-H bond oximation and thiomethylation reaction of methyl ketones using copper nitrate as the [NO] reagent: synthesis of thiohydroximic acids.

In this work, a highly efficient rongalite/iodine-mediated oxime formation reaction for the preparation of thiohydroximic acids from methyl ketones by employing copper nitrate as the [NO] reagent has been developed. Notably, copper nitrate participated as both a catalyst and the mild oximation reagent in the transformation. This reaction is highly efficient and facile, with a broad substrate scope, especially for fused ring skeleton substrates, heterocyclic skeleton substrates, and acetyl-substituted natural products. Mechanistic studies revealed that copper nitrate might be converted into a NO2 radical or the NO2 radical dimeric forms as an ion-pair equivalent to participate in the transformation.

Study on pyrolysis behavior of agricultural and forestry wastes using thermogravimetric‐Fourier transform infrared spectrometer (TG‐FTIR)

AbstractTo investigate the effective utilization of agricultural and forestry wastes for mitigating the shortage of primary energy and environmental pollution, the pyrolysis behavior of corn straw (CS), wheat straw (WS), and poplar sawdust (PS) was studied using thermogravimetric–Fourier transform infrared (TG‐FTIR) analysis. The activation energies and pyrolysis mechanism functions of different biomass types were calculated. The results showed that the functional group structures of the gaseous products generated from the pyrolysis of different biomass types were similar, mainly including OH, aliphatic CH, CO, aromatic ring skeleton, aromatic CH, and CO groups. These functional group structures mainly existed in oxygen‐containing compounds such as phenols, ketones, aldehydes, acids, esters, alcohols, and ethers. The pyrolysis process of agricultural and forestry wastes exhibited certain differences, with the PS undergoing thermal decomposition more easily, while the thermal decomposition mechanism functions of the two agricultural wastes (CS and WS) were similar. PS had a later initial release time for volatile matter, and the oxygen compounds produced by its pyrolysis were the highest, followed by WS and CS.

Sesquiterpene Backbones Generated by Sesquiterpene Cyclases: Formation of iso-Caryolan-1-ol and an Isoclovane.

New sesquiterpene backbones are accessible after incubation of caryolan-synthase (GcoA) and presilphiperfolan-8-β-ol synthase (BcBOT2) with a non-natural farnesyldiphosphate in which the central olefinic double bond is isomerized toward the methyl group. Two newly formed sesquiterpenoids are reported, a constitutional isomer of caryolan-1-ol (3), which we name iso-caryolan-1-ol (17), and the first terpenoid based on the isoclovane ring skeleton generated enzymatically thus far.

Onygenaleosides A-F, 6/5 Bicyclic Ring Skeleton Triterpene Glycosides with Insecticidal Activity from Onygenales sp. YX1425.

Six new squalene derived polyether glycosides, onygenaleosides A-F (1-6), that possess a 6/5 bicyclic fused ring skeleton were isolated from the cultures of Onygenales sp. YX1425, along with two known analogues (7 and 8). The planar structures of the new compounds were elucidated based on analysis of NMR and MS spectroscopy data, and the absolute configuration of 1 was determined by the advanced Mosher method and quantum chemical calculations. Compound 2 was active against Spodoptera frugiperda with an LC50 value of 193.4 ± 1.1 μg/mL.

A novel non-contact measurement strategy for large-size inflatable structures based on numerical predictions

The deformation characteristics of expansive inflatable structures, like airships, provide essential data for their operation in the stratosphere. However, due to rapid configuration changes in these structures with fluctuating air pressure, obtaining accurate morphological data quickly during testing can be challenging. This paper presents a precise method for predicting deformation in large-scale inflatable structures. A finite element method was employed to meticulously model the inflatable structure, underpinned by an inflatable ring skeleton support, and predict its potential maximum deformation points. Leveraging this predictive model as a guide, we proposed utilizing a laser scanning technique for non-contact measurements of the anticipated maximum deformation sites, aiming to discern the deformation patterns of the structure under varying air pressures. A good agreement between the non-contact measurement results and the numerical simulations affirms the efficiency and precision of the proposed methodology. This non-contact measurement strategy, grounded in finite element predictions, streamlines the measurement process, economizing on time and reducing complexity. Such an approach promises to be invaluable for expansive structures like airships. Furthermore, the insights derived from this non-contact method will be pivotal for anticipating the mechanical behaviors of full-scale stratospheric airships during their operations and for refining their design models.

A solid-diffusion-free hydronium-ion battery with ultra-long cycle life over 8000 cycles

Hydronium-ion batteries possess the advantages of high conductivity, good economic benefits and environmental friendliness. However, inorganic solid electrode materials always suffer from structure collapse because of their insertion mechanism, while organic solid electrode materials always face dissolution challenges. Herein, a hydronium-ion battery with a soluble methylene blue (MB) anode and a MnO2@graphite felt cathode is proposed, involving a -C=N / -C-NH group transition at the anode and MnO2/Mn2+ at the cathode. The anode exhibits a maximum capacity of 1324 μAh cm−2 at 2 mA cm−2 and excellent cycle stability over 7500 cycles with a retention of 93 %. In- and ex-situ characterizations uncover that MB possesses a highly reversible interfacial redox reaction and excellent ring skeleton stability. By coupling with MnO2@graphite felt cathode, the MB//MnO2 batteries deliver an energy density of 198 μWh cm−2 and outstanding long cycle stability over 8000 cycles. Moreover, the batteries exhibit an excellent electrochemical performance at a low temperature of -20 °C with a capacity of 220 μAh cm−2 at 0.4 mA cm−2 and a remarkable capacity retention of 80 % over 5500 cycles. The achieved results provide a path for high-stability hydronium-ion batteries.

Synergistic effect triggered by Fe2O3 and oxygen-induced hydroxyl radical enhances formation of amino-phenolic humic-like substance

Metal oxides play a promising role in the transformation of polyphenols and amino acids involved in naturally occurring humification. The objective of this study was to explore the synergistic interactions between Fe2O3 and O2 in the formation of humic substances under a controlled O2 atmosphere (0%, 21% and 40% O2 levels). The results indicate that an O2 level of 21% with Fe2O3 was optimal for humic acid (HA) production. Hydroxyl radicals (∙OH) formed and promoted the formation of HA in the presence of O2, and O2 improved the enhancing capacity of Fe2O3 by oxidizing Fe(II) to Fe(III). Moreover, the combination of these processes resulted in a synergistic improvement in humification. The evolution of functional groups in HA suggested that O2 promoted the formation of oxygen-containing groups such as lipids, and Fe2O3 was conducive to the formation of dark-coloured polymers during the darkening process of humification. Furthermore, the O2 level of 40% inhibited the formation of HA by reducing the transformation from Fe(III) to Fe(II). The XRD results showed few changes in the composition of Fe2O3 before and after humification, which indicated that Fe2O3 was a catalyst and an oxidant. The heterospectral UV–Vis/FTIR results suggested that ∙OH attacked phenolic rings to form the aromatic ring skeleton of HA and benefit the ring-opening copolymerization of humic precursors. In addition, structural equation modelling demonstrated that dissolved Fe was the key parameter affecting the HA yield. These findings provide new insights into the synergism of O2-mediated ∙OH production associated with metal oxide-facilitated humification.

Niduenes A−F, six functionalized sesterterpenoids with a pentacyclic 5/5/5/5/6 skeleton from endophytic fungus Aspergillus nidulans

Niduenes A−F (1−6), six novel sesterterpenoids with unprecedented 5/5/5/5/6 pentacyclic ring skeleton were isolated from endophytic fungus Aspergillus nidulans. Compounds 1 and 2 represent the first examples of aromatic pentacyclic sesterterpenoids. Their structures and configurations were elucidated by spectroscopic data and single-crystal X-ray diffraction analyses. Compound 4 demonstrated potent resensitization of SW620/AD300 cells to paclitaxel (PTX). Rhodamine 123 accumulation assay and docking analysis further support that 4 inhibitory the efflux function of P-glycoprotein (P-gp).

Study on the Influence of Coal Structure and Oxidation Performance by Endogenous Bacterium

In order to solve the defects of traditional coal spontaneous combustion prevention technology in a closed goaf, a strain of aerobic endogenous bacteria was isolated from coal and used as a blocking raw material. Based on the metabolic and reproductive characteristics of microorganisms, the experimental study on the inhibition of coal spontaneous combustion by microorganisms was carried out. The colonies were isolated and purified by the dilution concentration plate method and the scribing plate method. The growth morphology of microorganisms was analyzed, and the growth curve was determined. The strains were identified by seamless cloning technology for high-throughput sequencing. The surface morphology of coal was analyzed by SEM, the differences of oxidation characteristic temperature points were analyzed by TG–DTG–DSC images, a programmed heating experiment was used to analyze the concentration of the indicator gas CO, and the changes in microscopic groups before and after microbial action were analyzed by FTIR and XPS spectra. Therefore, the inhibition of coal oxidation by endogenous bacteria was verified from macroscopic and microscopic perspectives. The results show that the coal bacteria isolated from the coal is Lysinibacilus sp. After the culture of Lysinibacilus sp., the surface of the coal demonstrated less detritus, and was relatively smooth. In the early stage of low temperature oxidation of coal spontaneous combustion, the characteristic temperature point of coal oxidation and the reaction between coal and O2 could be delayed by Lysinibacilus sp., and the total heat release was reduced in the combustion process. Not only that, Lysinibacilus sp. could also reduce the CO concentration during coal heating. After the coal was decomposed by Lysinibacilus sp., the C=C thick ring skeleton structure had little effect; however, the aromatic substitution pattern changed. This bacterium had an effect on the C-O bond, reducing the percentage of -CH2- and increasing the percentage of -CH3. It might also use the crystalline water in coal for life activities. The carboxyl carbon in coal changed the most, with a decrease of 12.03%, so it might become the carbon source required for microbial growth. The reproductive metabolism of microorganisms also affected the form of nitrogen, and the percentage of pyridine nitrogen in coal was reduced. The ratio of single-bond carbon to double-bond carbon in raw coal was about 3:2, but after this bacterial action, the ratio of the two was about 1:1. The analytical conclusions of XPS and FTIR spectra were consistent, and the results supported each other.

Investigating the interactions of benzoylaconine and benzoylhypacoitine with human serum albumin: Experimental studies and computer calculations

Benzoylaconine (BAC) and benzoylhypacoitine (BHA), which are derived from Aconitine (AC) and hypacoitine (HA), are commonly used in Traditional Chinese Medicine (TCM). The pharmacokinetics of drugs can be affected by their binding to proteins. Therefore, it is necessary to investigate drug-protein interactions. In this study, multi-spectroscopic, molecular docking and dynamics simulation were applied to investigate the interaction mechanisms of human serum albumin (HSA) with BAC/BHA. The binding constants (Ka) of the HSA-BAC/BHA systems at 298 K were 1.70 × 105 and 1.88 × 105 M−1, respectively. Stable HSA-BAC/BHA complexes were formed under the static quenching mode. Hydrogen bonds and van der Waals forces are the main driving forces during the spontaneous process, and BAC/BHA were suggested embedding into the site I of HSA. Circular dichroism (CD) spectroscopy revealed a reduction of 1.9% and 1.4% in the α-helical structure content of HSA induced by BAC/BHA. The molecular docking found that the electronic structure domains of the nitrogen and benzene ring skeletons were critical in the complex formation. Furthermore, computer simulations provided insights into the stability changes and illustrated that the residues such as TRP-214, LEU-219, and LEU-238 acted as key residues in the binding process between aconitine analogs and HSA.

Aryldiazonium Salt-Triggered [2 + 2 + 1] Heteroannulation of Indoles by an Arylhydrazone Radical-Relayed 1,5-Hydrogen Atom Transfer.

An unprecedented three-component [2 + 2 + 1] annulation cascade of indoles with aryldiazonium salts and polyhalomethanes or acetone is presented by dual hydrogen atom transfer (HAT) and C-H functionalization. By employing readily accessible aryldiazonium salts as the radical initiators and electrophiles and polyhalomethanes and acetone as the C1 units, this method unprecedentedly constructs a pyrazole ring on an indole ring skeleton through the formation of two C-N bonds and a C-C bond in a single reaction.

Cationic complex-enhanced C-H stimulated Raman scattering in naphthalene-benzene solution.

Ring skeleton vibrations of aromatic series are dominant in Raman spectroscopy compared with the C-H stretching vibrations. When a laser-induced plasma (LIP) was generated in a mixed solution of naphthalene and benzene, an anomalous enhancement was observed in stimulated Raman scattering (SRS) of aromatic C-H stretching vibrations of naphthalene (3055 cm-1). However, SRS of C-H stretching vibrations of benzene at 3060 cm-1 disappeared. The LIP produced electrons and cations, and the transient production of ionized material contributed to the enhancement of SRS of C-H vibrations of naphthalene. Density functional theory calculations showed that the C-H Raman activity of the naphthalene molecules in (naphthalene-benzene)+ heterodimer was significantly enhanced compared with neutral naphthalene. In addition, SRS pulse durations were better compressed in pure benzene and naphthalene due to the self-focusing effect.

Influence of resin on the formation and development of mesophase in fluid catalytic cracking (FCC) slurry oil

Resin is one of the key components of fluid catalytic cracking slurry oil which is the raw material to form high-quality mesophase pitch. The effect of resin variations on the formation of mesophase was investigated in this paper. The results showed when the resin addition was from 0 to 20 wt%, the formation rate of mesophase remained basically invariable, but it was beneficial to the development of mesophase pitch with higher order degree. However, excessive additions of resin (>20 wt%) sharply accelerated the formation of mesophase due to the high concentration of reactive sites in the system, which shortened the time to form pitch with mesophase content close to 100%, adversely it led to the generation of mesophase pitch with lower order degree. In addition, the approximate molecular structure model of resin was constructed by various characterization methods. The aromatic ring skeleton of resin was dominated by 3–4 ring aromatic hydrocarbons. Resin also possessed structural features such as higher aromaticity, higher N and S content, larger molecular size, longer branched chains, more cyclic alkane structures and methylene bridges, and higher concentration of reactive sites than FCC-exR. Furthermore, an explanation of the effect of resin on the formation and development of mesophase with respect to the molecular structure characteristics was presumed. This work has important implications for regulating the raw material properties of FCC slurry oil and the preparation of high-quality mesophase pitch.