Sulfur-containing organic compounds display wide applications in the field of materials science,synthetic chemistry,and pharmaceutical industry.Thus,numerous synthetic strategies have been developed for the synthesis ...Sulfur-containing organic compounds display wide applications in the field of materials science,synthetic chemistry,and pharmaceutical industry.Thus,numerous synthetic strategies have been developed for the synthesis of sulfur-containing compounds in synthetic chemistry.In recent years,the utilization of sulfinic acids as versatile synthons has emerged as attractive and powerful approach to access various organosulfur compounds through sulfonylation,sulfinylation or sulfenylation reactions.In this review,we summarized the recent progress in the construction of various sulfur-containing compounds from sulfininc acids.Selected examples of substrates and the related reaction mechanisms are described here.This review intends to provide readers a comprehensive understanding on the synthesis of sulfur-containing molecules from sulfinic acids and provide help for future synthetic research.展开更多
Since the most sensitive resonance lines of nonmetallic elements are situated in vacuum ultraviolet region （below 190 nm）, they can not be directly determined with a common AAS instrument covering the spectral range...Since the most sensitive resonance lines of nonmetallic elements are situated in vacuum ultraviolet region （below 190 nm）, they can not be directly determined with a common AAS instrument covering the spectral range from 190 to 700 nm. The molecular absorption spectrometry is often used for the determination of nonmetallic elements. Syty et al. used vapor molecular absorption spectrometry（VMAS） to determine the sulfur dioxide and sulfide, in which a hydrogen hollow cathode lamp was used as a continuum source to determine SO;at 210 nm and a deuterium arc展开更多
The development of green and convenient methods for C–S bond formation has received significant attention because C–S bond widely occurs in many important pharmaceutical and biological compounds.Recently, visible-li...The development of green and convenient methods for C–S bond formation has received significant attention because C–S bond widely occurs in many important pharmaceutical and biological compounds.Recently, visible-light photoredox catalysis has been established as an efficient and general tool for the construction of C–C and C-heteroatom bonds. In this review, we have focused on the research on recent advances in C–S bond formation via visible-light photoredox catalysis, and the growing opportunities they present to the construction of complex chemical scaffolds for applications encompassing bioactive molecules synthesis, synthetic methodology development, and sulfur-containing drugs. We hope that this review will provide chemists with a synthetic tool that will open the door to further development of organsulfur chemistry.展开更多
Originating from“rocking-chair concept”,lithium-ion batteries(LIBs)have become one of the most important electrochemical energy storage technolo-gies,which have largely impacted our daily life.The utilization of ele...Originating from“rocking-chair concept”,lithium-ion batteries(LIBs)have become one of the most important electrochemical energy storage technolo-gies,which have largely impacted our daily life.The utilization of electrolyte additives in small quantities(≤5%by wt or vol)has been long viewed as an economical and efficient approach to regulate the properties of electrolyte and electrode–electrolyte interphases and consequently improve the cycling perfor-mance of LIBs.Among all the kinds of electrolyte additives,sulfur-containing compounds have gained significant attention due to their unique features in building stable electrode–electrolyte interphases and protect battery cells from overcharging.In this work,advances and progresses of sulfur-containing addi-tives used in LIBs are overviewed,with special attention paid to the working mechanisms of these electrolyte additives.Particularly,four representative sulfur-containing compounds(i.e.,1,3-propane sultone,prop-1-ene-1,3-sultone,1,3,2-dioxathiolane-2,2-dioxide,and ethylene sulfite)are comparatively dis-cussed concerning their impact on electrode–electrolyte interphases and cell per-formances.Future work on the development of sulfur-containing compounds as functional electrolyte additives is also provided.The present review is antici-pated to be not only a base document to access the status quo in this research domain but also a guideline to select specialized additives and electrolytes for practical applications.展开更多
To address the longstanding challenge in traditional carborane methodology of rapidly and efficiently constructing carboranyl-based polycyclic frameworks,Pd-catalyzed one-pot reactions between pyridyl-substituted nido...To address the longstanding challenge in traditional carborane methodology of rapidly and efficiently constructing carboranyl-based polycyclic frameworks,Pd-catalyzed one-pot reactions between pyridyl-substituted nidocarboranes and alkynes directly afford two distinct types of 2D-3D fused carboranyl polycyclic compounds:3a-3f,4a-4d.The structures of this series of compounds were characterized by nuclear magnetic resonance spectroscopy,single-crystal X-ray diffraction,and high-resolution mass spectrometry,and a plausible reaction mechanism was proposed.Crystal structures reveal that the multiple rings in such 2D-3D fused carboranyl polycyclic compounds exhibit a certain degree of coplanarity.Furthermore,these compounds exhibited properties distinct from those of conventional 2D polycyclic systems.CCDC:2481988,3c,2481990,3f,2481986,4d.展开更多
Light element compounds under high pressure display intriguing properties and applications,owing to their diverse bonding patterns and crystalline structures.However,the system of ternary Be-C-O compounds under high p...Light element compounds under high pressure display intriguing properties and applications,owing to their diverse bonding patterns and crystalline structures.However,the system of ternary Be-C-O compounds under high pressure,as the lightest representative of the IIA-IVA-VIA family,remains largely unexplored.Using a machine-learning-accelerated crystal structure search and first-principles calculations,Be-C-O phase diagrams are investigated at pressures ranging from 0 to 100 GPa.Four ternary compounds are proposed to be stable at corresponding pressures:BeCO_(3),Be_(2)CO_(4),Be_(2)C_(4)O_(3),and BeC_(4)O_(2).Analyses of electronic structure and chemical bonding further reveal how the structural diversity of these compounds is induced.Remarkably,Be_(2)C_(4)O_(3) and BeC_(4)O_(2) are recoverable to ambient conditions and possess both high energy density and high hardness.The volumetric energy densities of Be_(2)C_(4)O_(3) and BeC_(4)O_(2) could approach 9.03 and 7.94 kJ/cm^(3),respectively.The Vickers hardnesses of Be_(2)C_(4)O_(3) and BeC_(4)O_(2) are found to be close to 39.58 and 51.57 GPa,respectively.These findings demonstrate the structural and functional diversity of Be-C-O compounds under high pressure,providing guidance for further exploration of the IIA-IVA-VIA compounds.展开更多
Layered transition-metal compounds(LTMCs)feature stacked architectures,strong magnetic anisotropy,and tunable magnetic order,making them promising material platforms for low-power spintronic technologies and for enabl...Layered transition-metal compounds(LTMCs)feature stacked architectures,strong magnetic anisotropy,and tunable magnetic order,making them promising material platforms for low-power spintronic technologies and for enabling topological functionalities in the post-Moore era.Here we review recent progress on two-dimensional(2D)magnetism in LTMCs,emphasizing material taxonomy,intrinsic magnetic properties,and external-field controls.This review first presents a classification of LTMCs by crystal structure and chemistry—binary halides,chalcogenides,and ternary families(e.g.,MPX_(3),M_(m)X_(n)Te_(k),MnBi_(2)Te_(4))—followed by a summary of their coupling mechanisms,ordering temperatures,and dimensional effects.It then analyzes the modulation of exchange interactions,magnetic anisotropy,and topological states by electric-field gating,strain engineering,and ion intercalation,with representative experimental demonstrations.Notable advances include room-temperature ferromagnetic metals and semiconductors,observation of the quantum anomalous Hall effect(QAHE)in MnBi2Te4,and synergistic control of magnetic-topological states under multiple external stimuli.Persistent challenges involve the limited availability of intrinsic 2D magnetic semiconductors with high Curie temperatures(Tc),incomplete understanding of the microscopic couplings at interfaces and under quantum confinement,and device-level stability.We conclude by outlining opportunities that lie in the integration of multiscale characterization,first-principles theory,and cross-scale fabrication to precisely co-engineer magnetism,topology,and electronic structure,thereby advancing LTMCs toward spintronic and topological-quantum applications.展开更多
To elucidate the variations in volatile organic compounds(VOCs)among widely cultivated japonica rice varieties in China and offer novel perspectives on flavor formation during rice-based beer brewing,nine prevalent Ch...To elucidate the variations in volatile organic compounds(VOCs)among widely cultivated japonica rice varieties in China and offer novel perspectives on flavor formation during rice-based beer brewing,nine prevalent Chinese japonica rice variaties were selected as experimental materials.Comprehensive analyses were conducted to investigate three key aspects:differences in VOCs among the selected japonica rice varieties,the retention of rice VOCs after beer brewing,and the influence of rice additives on beer sensory characteristics.Results showed that the total contents of VOCs in Wuyoudao 4(WYD4)and Nangeng 9108(NG9108)were significantly higher than those in the other varieties(P<0.05).The popcorn-flavor compound 2-acetyl-1-pyrroline(2-AP)was detected in Suigeng 27(SG27,26.80 ng/g),WYD4(25.25 ng/g),NG9108(21.18 ng/g),and Suigeng 18(SG18,11.62 ng/g),with the levels in the first three varieties significantly higher than those in SG18.Circular heatmap analysis classified the nine japonica varieties into three major categories:fragrant japonica from North China(WYD4),fragrant japonica from South China(NG9108),and others.Ten characteristic VOCs across the japonica varieties were identified by headspace solid-phase microextraction gas chromatography-mass spectrometry(HS-SPME-GC-MS).Using beer brewed with whole wheat as the control,we analyzed the VOCs and sensory characteristics of beer brewed with fragrant japonica rice as an additive.We found that rice VOCs were not detected in beer brewed with fragrant japonica rice as an additive.Adding rice promoted the formation of banana-like flavors and reduced the beer’s richness and mellowness.展开更多
Carbenes as one of the most important class of intermediates have been widely utilized in various organic synthetic transformations.Carbene insertion-initiated ring-opening reactions of cyclic ethers offer a valuable ...Carbenes as one of the most important class of intermediates have been widely utilized in various organic synthetic transformations.Carbene insertion-initiated ring-opening reactions of cyclic ethers offer a valuable strategy for constructing new carbon-oxygen bonds.In comparison with traditional thermal or metal-mediated carbene transfer reactions,visible-light-promoted multi-component reaction strategy provides a mild and eco-friendly approach to access densely functionalized molecules.Recently,visible-light-induced multi-component carbene transfer reactions of diazo compounds have been rapidly developed and attracted a great deal of research interest of chemists owing to their advantages of simple operation,mild condition,high atom economy and rich structural diversity.This paper summarizes the recent research progress on the visible-light-promoted multi-component carbene transfer reactions of diazo compounds via ring-opening of cyclic ethers with various nucleophiles.The reaction patterns of different nucleophiles and their corresponding mechanism are described in this review.The future research direction and challenges in this area are also discussed.展开更多
Chili fermentation is one of the most important processes in the production of Pixian Douban(PXDB),which determines the flavor and product quality of PXDB.However,the maturity of fermented chili mainly depends on empi...Chili fermentation is one of the most important processes in the production of Pixian Douban(PXDB),which determines the flavor and product quality of PXDB.However,the maturity of fermented chili mainly depends on empirical judgment,which can not satisfy the need for standardized production of PXDB.Therefore,this study aimed to investigate volatile and non-volatile substances during the maturation process and to find markers related to the maturity of fermented chili.Two-dimensional gas chromatography-mass spectrometry(GC×GC-MS)combined with multivariate statistical analysis and relative odor activity values(ROAV)analysis revealed that 2-methoxy-3-isobutyl pyrazine,linalool,3-(methylthio)propionaldehyde,myrcene,and decanal(ROAV≥1,VIP>1,P<0.05)were regarded as potentially active aromatic markers for differentiating fermentation time.Additionally,ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLCQTOF-MS)combined with multivariate statistical analysis revealed that 25 compounds could serve as differentiated non-volatile compounds.The correlation of maturity-related physicochemical indicators with volatile and nonvolatile compounds revealed that four volatile compounds(2-methoxy-3-isobutylpyrazine,linalool,myrcene,and decanal)along with seven non-volatile compounds could serve as markers for evaluating the maturity of fermented chili.This study is expected to establish a standard for the determination of the maturity the fermented chili and lay the foundation for intelligent production of PXDB.展开更多
A trace analytical method based on solid-phase extraction gas chromatography-tandem mass spectrometry(SPE–GC–MS/MS)was developed for the rapid detection of 256 semi-volatile organic compounds(SVOCs),including 25 pol...A trace analytical method based on solid-phase extraction gas chromatography-tandem mass spectrometry(SPE–GC–MS/MS)was developed for the rapid detection of 256 semi-volatile organic compounds(SVOCs),including 25 polycyclic aromatic hydrocarbons(PAHs),70 polychlorinated biphenyls(PCBs),123 pesticides,20 phthalate esters(PAEs),4 organophosphate esters(OPEs),9 synthetic musks(SMs),and 5 UV filters(UVs)in water.No-tably,this method provided a decent linearity of calibration standards(R^(2)>0.999),excellent method limits of quantification(MLOQs)(0.12–11.41 ng/L),satisfactory matrix spiking recovery rates(60.4%–126%),and high precision(intra-day relative standard deviations(RSDs):1.0%–10.0%,inter-day RSDs:3.0%–15.0%,and inter-week RSDs:3.4%–15.7%),making it suitable for trace-level studies.Statistical analysis revealed that SVOCs with higher volatility exhibited enhanced recovery rates.Validation of the methodology involved analyzing SVOCs in real spring water and river water samples.Twenty-seven SVOCs were detected in spring water and 58 in river water,with an average concentration of 631.73 and 16,095 ng/L,respectively.Among the detected SVOCs,PAEs constituted the predominant proportion.This study underscored the presence of SVOCs contamination specifi-cally within the spring water,although SVOCs concentrations in river water were significantly greater than those found in spring water.In summary,this sensitive method based on SPE–GC–MS/MS was successfully developed and validated for the rapid analysis of a diverse array of 256 SVOCs at trace levels in water,including not only the traditional highly valued PAHs,PCBs,pesticides,and PAEs,but also the emerging OPEs,UVs,and SMs.展开更多
Endogenous hydrogen systems,consisting of metal–organic coordination catalysts and alcohols,have been widely applied for the transfer hydrogenation(TH)of biomass-derived carbonyl compounds in recent years.Metal-organ...Endogenous hydrogen systems,consisting of metal–organic coordination catalysts and alcohols,have been widely applied for the transfer hydrogenation(TH)of biomass-derived carbonyl compounds in recent years.Metal-organic coordination catalysts showed satisfactory ability of TH in the secondary alcohols,but most of them could not effectively employ the cheaper primary alcohols as hydrogen donors.Furthermore,they commonly contained high metal contents,which also led to low catalytic efficiency in significant measure.In this work,we constructed a novel magnesium single-atom catalyst(Mg-NC)with merely 0.37 wt%Mg by means of a combined self-assembly and pyrolysis strategy.The characterization results indicated that Mg was atomically dispersed and it was coordinated with four pyridinic-N in Mg-NC.Due to the obvious electron transfer from Mg to its coordinated pyridinic-N,Mg–N_(4)active centers displayed high Lewis acid-base strength with abundant content,which brought remarkable catalytic activity.When Mg-NC was used for the TH of 5-hydroxymethylfurfural(HMF)in ethanol(EtOH),2,5-bis(hydroxymethyl)furan(BHMF)yield was up to 96.3%with high productivity of 19.85 molBHMF mol_(Mg)^(−1)h^(−1)at 150°C for 5 h.More interestingly,the process of TH over Mg-NC in EtOH was proved to proceed via the hydrogen radical mechanism.Additionally,Mg-NC exhibited powerful catalytic universality;it could not only utilize other primary alcohols(such as n-propanol and n-butanol)as hydrogen donors,but also catalyze the TH of other carbonyl compounds(such as furfural,5-methylfurfural,benzaldehyde,cyclohexanone,and levulinic acid).Overall,this work offered some important clues and references to reinforce the hydrogen-supplying ability of primary alcohols in the TH of various biomass-derived carbonyl compounds to high-value fine chemicals.展开更多
In the conventional water treatment process,algae have a propensity to breach the filter barriers and potentially seep into the water distribution system,leading to an elevation in taste and odor compounds(T&O com...In the conventional water treatment process,algae have a propensity to breach the filter barriers and potentially seep into the water distribution system,leading to an elevation in taste and odor compounds(T&O compounds).This investigation delved into the seasonal fluctuations of algae penetration and the production of T&O compounds within the treatment units of Reservoir Water Plant 1(W1)and River Water Plant 2(W2).The findings indicated that despite the application of the‘pre-oxidation,coagulation and sedimentation(PCS),sand filtration,and disinfection’process,certain robust-walled filamentous Cyanobacteria,Bacillariophyta species,and small Chlorophyta genera managed to bypass the filters.The leakage of algal cells during autumn at W1 was particularly striking,with a peak of 1,170,000 cells/L.The concurrent assessment of the potential for T&O compound formation revealed an alarming high potential for 2-methylisoborneol(2-MIB)in the water leaving the plants,with concentrations soaring to 197.20 ng/L at W1 in autumn and 54.78 ng/L at W2 in summer.This underscores the significant capacity of residual algal cells to generate T&O compounds.Tracking the retention and penetration dynamics of algal cells across each drinking water treatment stage is crucial for surface water treatment facilities to develop effective operational and management strategies,thereby enhancing the safety and quality of drinking water for the end consumer.展开更多
Carbonyl compounds play a pivotal role in the formation of secondary pollutants such as O_(3) and SOA,signifi-cantly impacting air quality and human health.This study extended the observation period compared to previo...Carbonyl compounds play a pivotal role in the formation of secondary pollutants such as O_(3) and SOA,signifi-cantly impacting air quality and human health.This study extended the observation period compared to previous research,providing a long-term perspective on carbonyl compound variations and their environmental implica-tions.Atmospheric observations were conducted at Beijing(BJ)and Xianghe(XH)during the summer and winter months of 2018,2019,and 2023 to study the sources and impacts of carbonyl compounds in typical urban areas and peri‑urban areas.Notably,concentrations in the summer of 2023 increased compared to 2018 and 2019.The predominant carbonyl compounds—formaldehyde,acetaldehyde,and acetone—accounted for over 60%of the total.The mean values of OFP in BJ ranged from 18.55 to 58.61μg/m3,lower than those in XH(29.82 to 65.48μg/m3),with formaldehyde and acetaldehyde contributing over 80%of the total.SOAP exhibited a similar pattern,with values in XH(69.21 to 508.55μg/m3)significantly exceeding those in BJ(34.47 to 159.78μg/m3).The PMF model highlighted vehicle exhaust,secondary pollution,and biomass combustion as major sources of carbonyl compounds,emphasizing differences in source contributions between the two regions.This study’s com-parative analysis over different years and locations provides new insights into the dynamic changes in carbonyl compounds and their environmental importance.These results not only reinforce the importance of carbonyl compounds regulation but also offer a valuable reference for evaluating and refining emission control strategies during this period.展开更多
The search for high-abundance compounds containing rare earth elements to develop high-performance magnetic refrigeration materials for hydrogen liquefaction has become a particularly attractive research direction.We ...The search for high-abundance compounds containing rare earth elements to develop high-performance magnetic refrigeration materials for hydrogen liquefaction has become a particularly attractive research direction.We successfully manipulated the magnetic interactions in tetragonal rare earth carbides(RE_(3)C_(4))by doping them with boron(B)element,transforming their state from antiferromagnetic to ferromagnetic.Theoretical calculations and experimental results indicate that the transition in magnetic interactions may be due to the synergistic effects of electronic structure and lattice distortions.Building on this,further doping with holmium(Ho)element was used to adjust the magnetic transition temperature of the system.The results show that the magnetic transition temperature of this series of compounds can be effectively altered within the range of 26-42.8 K.By optimizing the composition of rare earth elements,a series of novel candidate materials exhibiting significant magnetocaloric effects within the temperature range required for hydrogen liquefaction is successfully developed.展开更多
OBJECTIVE:To eliminate ineffective or interfering compounds from the eight absorbed compounds(8ACs),identify the primary ACs that represent the multifunctional therapeutic effects of Zhiqiao(Fructus Aurantii Submaturu...OBJECTIVE:To eliminate ineffective or interfering compounds from the eight absorbed compounds(8ACs),identify the primary ACs that represent the multifunctional therapeutic effects of Zhiqiao(Fructus Aurantii Submaturus)and Houpo(Cortex Magnoliae Officinalis)(FM),along with elucidating their underlying mechanisms.METHODS:Key multifunctional ACs were screened through ex vivo-to-in vitro extrapolation(ex vivo dose=serum concentration)and validated in vivo,with efficacy assessed via contribution(dose=FM content).Functional magnetic resonance imaging analyzed brain regions's blood oxygen level-dependent(BOLD)changes,and the molecular mechanisms were analyzed by transcriptome of the dentate gyrus(DG).RESULTS:The results showed that representative 2ACs(Nobiletin+Magnolol)and 3ACs(Nobiletin+Magnolol+Meranzin hydrate)screened on ex vivo experiment by the criteria of contribution ranking contributed 80.72%-126.74%of the antidepressant and prokinetic effects of the FM(improvement of depressive-like behaviours,gastrointestinal disorder,monoamine neurotransmitters,ghrelin,endocrine hormones,pro-inflammatory factors,oxidative stress indicators).In addition,3ACs demonstrated superiority over 2ACs in improving depression and levels of multiple stress mediators.Zhiqiao(Fructus Aurantii Submaturus)(FRA)reduced acute stress-induced hyperactivation of the cingulate cortex,thalamus,hypothalamus,and entorhinal cortex and elevated BOLD signaling in the insular cortex,temporal association cortex.Furthermore,FRA upregulated pathways of neurotransmitter receptor activity and serotonergic synaptic function and downregulated inflammation-related pathways at the genetic level.CONCLUSION:2ACs and 3ACs closely reflected FM's multifunctional effect in antidepressant and prokinetic.FRA restores stress-impaired neural connectivity in functional brain regions and improves synaptic plasticity and neurogenesis at the genetic level.展开更多
After the application of methionine, a progressive and significant increase occurred in five volatile organic sulfur compounds （VOSCs）： methanethiol （MESH）, dimethyl sulfide （DMS）, dime^yl disulfide （DMDS）, d...After the application of methionine, a progressive and significant increase occurred in five volatile organic sulfur compounds （VOSCs）： methanethiol （MESH）, dimethyl sulfide （DMS）, dime^yl disulfide （DMDS）, dimethyl trisulfide （DMTS） and dimethyl tetrasulfide （DMTeS）. Even in the untreated control without a methionine addition, methionine and its catabolites （VOSCs, mainly DMDS） were found in considerable amounts that were high enough to account for the water＇s offensive odor. However, blackening only occurred in two methionine-amended treatments. The VOSCs production was observed to precede black color development, and the reaching of a peak value for total VOSCs was often followed by water blackening. The presence of glucose stimulated the degradation of methionine while postponing the occurrence of the black color and inhibiting the production of VOSCs. In addition, DMDS was found to be the most abundant species produced after the addition of methionine alone, and DMTeS appeared to be the most important compound produced after the addition of methionine＋glucose. These results suggest that methionine acted as an important precursor of the VOSCs in lakes suffering from algea-induced black bloom. The existence of glucose may change the transformation pathway of methionine into VOSCs to form larger molecular weight compounds, such as DMTS and DMTeS.展开更多
The zigzag nitrogen chain,similar to the Ch-N structure,has long been considered as a potential high-energy-density structure.However,all the previously predicted zigzag N-chain structures,similar to Ch-N,exhibited im...The zigzag nitrogen chain,similar to the Ch-N structure,has long been considered as a potential high-energy-density structure.However,all the previously predicted zigzag N-chain structures,similar to Ch-N,exhibited imaginary frequencies in their phonon spectra at 0 GPa.Here,we conducted a systematic investigation of P-N compounds using first-principles calculations,uncovering a series of structurally similar stable phases,C2/m-PN_(x)(x=6,8,10,12,and 14),in which N forms zigzag N chains similar to those in Ch-N.In P-N compounds,the longest zigzag N-chain,which can theoretically remain stable under ambient pressure,is the N-chain composed of 14 N atoms in C2/m-PN14.If the N-chain continues to grow,imaginary interchain vibrational frequencies arise in the system.Notably,N chains with an even number of atoms were more likely to be energetically favorable.The five C2/m-PN_(x) phases and one metastable phase(R-PN_(6))exhibited remarkable stability and excellent detonability at ambient pressure,indicating that they are promising candidates for high-energy-density materials.In addition,R-PN_(6) was the first structure to stabilize the N_(6) ring through covalent bonding,with the covalent network contributing to its high hardness(47.59 GPa).展开更多
Structural and thermodynamic parameters of 56 oxygen-containing and 56 sulfur- containing organic compounds were computed at the B3LPY/6-311G＊＊ level using density functional theory （DFT） method. Furthermore,the d...Structural and thermodynamic parameters of 56 oxygen-containing and 56 sulfur- containing organic compounds were computed at the B3LPY/6-311G＊＊ level using density functional theory （DFT） method. Furthermore,the dependent equations between the experimental data of boiling points （Tb） and theoretical parameters were proposed with SPSS12.0 for windows software,whose correlation coefficients R2 are 0.933 and 0.945. These dependent equations were validated by cross-validation method （q2 are 0.923 and 0.929,respectively）. VIF （variance inflation factors） and t-value methods were also used to verify the significance and self-correlationship of each variable. Results indicate that our dependent equation exhibits good prediction ability,and molecular polarizability （α） is the main factor affecting the Tb of oxygen- and sulfur-containing organic compounds. To our interest,obvious dependence could also be found among the oxygen- and sulfur-containing organic compounds＇ experimental data of boiling points （Tb） with R^2 of 0.857.展开更多
The role of the sulfur 3d orbitals in bond formation is discussed by taking into account the influence of the environment on the orbitals of the sulfur atom in the molecules. The ca cula- tion results of a series of p...The role of the sulfur 3d orbitals in bond formation is discussed by taking into account the influence of the environment on the orbitals of the sulfur atom in the molecules. The ca cula- tion results of a series of prototype molecules containing sulfur such as SF_2, SF_4, NSF_3, SF_1, H_2S are reported. It is convincingly shown that in highly electronegative environment the energy levels of the sulfur 3d orbitals are reduced to the vicinity of those of the ligand valence orbitals and their spatial distributions are contracted to the bonding area, and therefore they can participate in bond formation to a certain extent, which is enhanced by the formation of the d-p π back bonds. It seems that the result reported in this paper is helpful for the solution of the long-standing debate about the sulfur 3d orbital participation in bond formation.展开更多
基金supported by the Youth Innovation Technology Project of Higher School in Shandong Province(No.2019KJC021)Qinghai Science and Technology Achievement Transformation Project(No.2019-SF-122)Qinghai Key Laboratory of Tibetan Medicine Research(No.2021-ZJ-Y03)。
文摘Sulfur-containing organic compounds display wide applications in the field of materials science,synthetic chemistry,and pharmaceutical industry.Thus,numerous synthetic strategies have been developed for the synthesis of sulfur-containing compounds in synthetic chemistry.In recent years,the utilization of sulfinic acids as versatile synthons has emerged as attractive and powerful approach to access various organosulfur compounds through sulfonylation,sulfinylation or sulfenylation reactions.In this review,we summarized the recent progress in the construction of various sulfur-containing compounds from sulfininc acids.Selected examples of substrates and the related reaction mechanisms are described here.This review intends to provide readers a comprehensive understanding on the synthesis of sulfur-containing molecules from sulfinic acids and provide help for future synthetic research.
文摘Since the most sensitive resonance lines of nonmetallic elements are situated in vacuum ultraviolet region （below 190 nm）, they can not be directly determined with a common AAS instrument covering the spectral range from 190 to 700 nm. The molecular absorption spectrometry is often used for the determination of nonmetallic elements. Syty et al. used vapor molecular absorption spectrometry（VMAS） to determine the sulfur dioxide and sulfide, in which a hydrogen hollow cathode lamp was used as a continuum source to determine SO;at 210 nm and a deuterium arc
基金supported by the Natural Science Foundation of Shandong Province (No. ZR2016JL012)Hunan Provincial Natural Science Foundation of China (No. 2019JJ20008)the Scientific Research Foundation of Qingdao University of Science and Technology (No. 1203043003457)。
文摘The development of green and convenient methods for C–S bond formation has received significant attention because C–S bond widely occurs in many important pharmaceutical and biological compounds.Recently, visible-light photoredox catalysis has been established as an efficient and general tool for the construction of C–C and C-heteroatom bonds. In this review, we have focused on the research on recent advances in C–S bond formation via visible-light photoredox catalysis, and the growing opportunities they present to the construction of complex chemical scaffolds for applications encompassing bioactive molecules synthesis, synthetic methodology development, and sulfur-containing drugs. We hope that this review will provide chemists with a synthetic tool that will open the door to further development of organsulfur chemistry.
基金Fundamental Research Funds for the Central Universities,Grant/Award Number:2020kfyXJJS095National Natural Science Foundation of China,Grant/Award Number:51172083。
文摘Originating from“rocking-chair concept”,lithium-ion batteries(LIBs)have become one of the most important electrochemical energy storage technolo-gies,which have largely impacted our daily life.The utilization of electrolyte additives in small quantities(≤5%by wt or vol)has been long viewed as an economical and efficient approach to regulate the properties of electrolyte and electrode–electrolyte interphases and consequently improve the cycling perfor-mance of LIBs.Among all the kinds of electrolyte additives,sulfur-containing compounds have gained significant attention due to their unique features in building stable electrode–electrolyte interphases and protect battery cells from overcharging.In this work,advances and progresses of sulfur-containing addi-tives used in LIBs are overviewed,with special attention paid to the working mechanisms of these electrolyte additives.Particularly,four representative sulfur-containing compounds(i.e.,1,3-propane sultone,prop-1-ene-1,3-sultone,1,3,2-dioxathiolane-2,2-dioxide,and ethylene sulfite)are comparatively dis-cussed concerning their impact on electrode–electrolyte interphases and cell per-formances.Future work on the development of sulfur-containing compounds as functional electrolyte additives is also provided.The present review is antici-pated to be not only a base document to access the status quo in this research domain but also a guideline to select specialized additives and electrolytes for practical applications.
文摘To address the longstanding challenge in traditional carborane methodology of rapidly and efficiently constructing carboranyl-based polycyclic frameworks,Pd-catalyzed one-pot reactions between pyridyl-substituted nidocarboranes and alkynes directly afford two distinct types of 2D-3D fused carboranyl polycyclic compounds:3a-3f,4a-4d.The structures of this series of compounds were characterized by nuclear magnetic resonance spectroscopy,single-crystal X-ray diffraction,and high-resolution mass spectrometry,and a plausible reaction mechanism was proposed.Crystal structures reveal that the multiple rings in such 2D-3D fused carboranyl polycyclic compounds exhibit a certain degree of coplanarity.Furthermore,these compounds exhibited properties distinct from those of conventional 2D polycyclic systems.CCDC:2481988,3c,2481990,3f,2481986,4d.
基金supported by the National Key R&D Program of China(Grant Nos.2018YFA0703404 and 2017YFA0403704)the National Natural Science Foundation of China(Grant Nos.11774121 and 91745203)the Program for Changjiang Scholars and Innovative Research Team in University(Grant No.IRT_15R23).
文摘Light element compounds under high pressure display intriguing properties and applications,owing to their diverse bonding patterns and crystalline structures.However,the system of ternary Be-C-O compounds under high pressure,as the lightest representative of the IIA-IVA-VIA family,remains largely unexplored.Using a machine-learning-accelerated crystal structure search and first-principles calculations,Be-C-O phase diagrams are investigated at pressures ranging from 0 to 100 GPa.Four ternary compounds are proposed to be stable at corresponding pressures:BeCO_(3),Be_(2)CO_(4),Be_(2)C_(4)O_(3),and BeC_(4)O_(2).Analyses of electronic structure and chemical bonding further reveal how the structural diversity of these compounds is induced.Remarkably,Be_(2)C_(4)O_(3) and BeC_(4)O_(2) are recoverable to ambient conditions and possess both high energy density and high hardness.The volumetric energy densities of Be_(2)C_(4)O_(3) and BeC_(4)O_(2) could approach 9.03 and 7.94 kJ/cm^(3),respectively.The Vickers hardnesses of Be_(2)C_(4)O_(3) and BeC_(4)O_(2) are found to be close to 39.58 and 51.57 GPa,respectively.These findings demonstrate the structural and functional diversity of Be-C-O compounds under high pressure,providing guidance for further exploration of the IIA-IVA-VIA compounds.
基金supported by the National KeyR&D Program of China(Grant No.2024YFB3817400)the National Natural Science Foundation of China(Grants No.12274276 and No.U24A6002)+1 种基金the Natural Science Foundation of Shanxi Province(China)(Grant No.202403021223008)Supported by Scientific and Technology Innovation Programs of Higher Education Institutions in Shanxi(Grant No.2024Q017 and No.2025L043).
文摘Layered transition-metal compounds(LTMCs)feature stacked architectures,strong magnetic anisotropy,and tunable magnetic order,making them promising material platforms for low-power spintronic technologies and for enabling topological functionalities in the post-Moore era.Here we review recent progress on two-dimensional(2D)magnetism in LTMCs,emphasizing material taxonomy,intrinsic magnetic properties,and external-field controls.This review first presents a classification of LTMCs by crystal structure and chemistry—binary halides,chalcogenides,and ternary families(e.g.,MPX_(3),M_(m)X_(n)Te_(k),MnBi_(2)Te_(4))—followed by a summary of their coupling mechanisms,ordering temperatures,and dimensional effects.It then analyzes the modulation of exchange interactions,magnetic anisotropy,and topological states by electric-field gating,strain engineering,and ion intercalation,with representative experimental demonstrations.Notable advances include room-temperature ferromagnetic metals and semiconductors,observation of the quantum anomalous Hall effect(QAHE)in MnBi2Te4,and synergistic control of magnetic-topological states under multiple external stimuli.Persistent challenges involve the limited availability of intrinsic 2D magnetic semiconductors with high Curie temperatures(Tc),incomplete understanding of the microscopic couplings at interfaces and under quantum confinement,and device-level stability.We conclude by outlining opportunities that lie in the integration of multiscale characterization,first-principles theory,and cross-scale fabrication to precisely co-engineer magnetism,topology,and electronic structure,thereby advancing LTMCs toward spintronic and topological-quantum applications.
基金supported by the Natural Science Foundation of Zhejiang Province,China(Grant No.LTGN24C020004)the Enterprise Cooperation Project,China(Grant No.HRJYH-202330)+1 种基金the Zhejiang Province Pioneer and Bellwethers Research&Development Project of Science and Technology,China(Grant No.2023C02014)the Central Public-Interest Scientific Institution Basal Research Fund,China(Grant No.CPSIBRFCNRRI-202303).
文摘To elucidate the variations in volatile organic compounds(VOCs)among widely cultivated japonica rice varieties in China and offer novel perspectives on flavor formation during rice-based beer brewing,nine prevalent Chinese japonica rice variaties were selected as experimental materials.Comprehensive analyses were conducted to investigate three key aspects:differences in VOCs among the selected japonica rice varieties,the retention of rice VOCs after beer brewing,and the influence of rice additives on beer sensory characteristics.Results showed that the total contents of VOCs in Wuyoudao 4(WYD4)and Nangeng 9108(NG9108)were significantly higher than those in the other varieties(P<0.05).The popcorn-flavor compound 2-acetyl-1-pyrroline(2-AP)was detected in Suigeng 27(SG27,26.80 ng/g),WYD4(25.25 ng/g),NG9108(21.18 ng/g),and Suigeng 18(SG18,11.62 ng/g),with the levels in the first three varieties significantly higher than those in SG18.Circular heatmap analysis classified the nine japonica varieties into three major categories:fragrant japonica from North China(WYD4),fragrant japonica from South China(NG9108),and others.Ten characteristic VOCs across the japonica varieties were identified by headspace solid-phase microextraction gas chromatography-mass spectrometry(HS-SPME-GC-MS).Using beer brewed with whole wheat as the control,we analyzed the VOCs and sensory characteristics of beer brewed with fragrant japonica rice as an additive.We found that rice VOCs were not detected in beer brewed with fragrant japonica rice as an additive.Adding rice promoted the formation of banana-like flavors and reduced the beer’s richness and mellowness.
基金Science and Technology Foundation of Guizhou Province(No.QKHJC-ZK[2024]654)Guizhou Provincial University Key Laboratory of Advanced Functional Electronic Materials(No.QJJ[2023]021).
文摘Carbenes as one of the most important class of intermediates have been widely utilized in various organic synthetic transformations.Carbene insertion-initiated ring-opening reactions of cyclic ethers offer a valuable strategy for constructing new carbon-oxygen bonds.In comparison with traditional thermal or metal-mediated carbene transfer reactions,visible-light-promoted multi-component reaction strategy provides a mild and eco-friendly approach to access densely functionalized molecules.Recently,visible-light-induced multi-component carbene transfer reactions of diazo compounds have been rapidly developed and attracted a great deal of research interest of chemists owing to their advantages of simple operation,mild condition,high atom economy and rich structural diversity.This paper summarizes the recent research progress on the visible-light-promoted multi-component carbene transfer reactions of diazo compounds via ring-opening of cyclic ethers with various nucleophiles.The reaction patterns of different nucleophiles and their corresponding mechanism are described in this review.The future research direction and challenges in this area are also discussed.
基金supported by the Sichuan Provincial Department of Science and Technology(2024ZHCG0086)the Chongqing Science and Technology Commission(cstc2021jscx-cylhX0014).
文摘Chili fermentation is one of the most important processes in the production of Pixian Douban(PXDB),which determines the flavor and product quality of PXDB.However,the maturity of fermented chili mainly depends on empirical judgment,which can not satisfy the need for standardized production of PXDB.Therefore,this study aimed to investigate volatile and non-volatile substances during the maturation process and to find markers related to the maturity of fermented chili.Two-dimensional gas chromatography-mass spectrometry(GC×GC-MS)combined with multivariate statistical analysis and relative odor activity values(ROAV)analysis revealed that 2-methoxy-3-isobutyl pyrazine,linalool,3-(methylthio)propionaldehyde,myrcene,and decanal(ROAV≥1,VIP>1,P<0.05)were regarded as potentially active aromatic markers for differentiating fermentation time.Additionally,ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLCQTOF-MS)combined with multivariate statistical analysis revealed that 25 compounds could serve as differentiated non-volatile compounds.The correlation of maturity-related physicochemical indicators with volatile and nonvolatile compounds revealed that four volatile compounds(2-methoxy-3-isobutylpyrazine,linalool,myrcene,and decanal)along with seven non-volatile compounds could serve as markers for evaluating the maturity of fermented chili.This study is expected to establish a standard for the determination of the maturity the fermented chili and lay the foundation for intelligent production of PXDB.
基金supported by the National Natural Science Foundation of China(No.51939009)Shenzhen Science and Technology Program(Nos.JCYJ20241202125905008 and GXWD20201231165807007-20200810165349001).
文摘A trace analytical method based on solid-phase extraction gas chromatography-tandem mass spectrometry(SPE–GC–MS/MS)was developed for the rapid detection of 256 semi-volatile organic compounds(SVOCs),including 25 polycyclic aromatic hydrocarbons(PAHs),70 polychlorinated biphenyls(PCBs),123 pesticides,20 phthalate esters(PAEs),4 organophosphate esters(OPEs),9 synthetic musks(SMs),and 5 UV filters(UVs)in water.No-tably,this method provided a decent linearity of calibration standards(R^(2)>0.999),excellent method limits of quantification(MLOQs)(0.12–11.41 ng/L),satisfactory matrix spiking recovery rates(60.4%–126%),and high precision(intra-day relative standard deviations(RSDs):1.0%–10.0%,inter-day RSDs:3.0%–15.0%,and inter-week RSDs:3.4%–15.7%),making it suitable for trace-level studies.Statistical analysis revealed that SVOCs with higher volatility exhibited enhanced recovery rates.Validation of the methodology involved analyzing SVOCs in real spring water and river water samples.Twenty-seven SVOCs were detected in spring water and 58 in river water,with an average concentration of 631.73 and 16,095 ng/L,respectively.Among the detected SVOCs,PAEs constituted the predominant proportion.This study underscored the presence of SVOCs contamination specifi-cally within the spring water,although SVOCs concentrations in river water were significantly greater than those found in spring water.In summary,this sensitive method based on SPE–GC–MS/MS was successfully developed and validated for the rapid analysis of a diverse array of 256 SVOCs at trace levels in water,including not only the traditional highly valued PAHs,PCBs,pesticides,and PAEs,but also the emerging OPEs,UVs,and SMs.
基金financially supported by the National Natural Science Foundation of China(U22A20421)the Qinglan Project of Jiangsu Province,the 533 Talent Program of Huaian City,and the College Students’Innovative Entrepreneurial Training Plan Program of Jiangsu Province(X202510323027).
文摘Endogenous hydrogen systems,consisting of metal–organic coordination catalysts and alcohols,have been widely applied for the transfer hydrogenation(TH)of biomass-derived carbonyl compounds in recent years.Metal-organic coordination catalysts showed satisfactory ability of TH in the secondary alcohols,but most of them could not effectively employ the cheaper primary alcohols as hydrogen donors.Furthermore,they commonly contained high metal contents,which also led to low catalytic efficiency in significant measure.In this work,we constructed a novel magnesium single-atom catalyst(Mg-NC)with merely 0.37 wt%Mg by means of a combined self-assembly and pyrolysis strategy.The characterization results indicated that Mg was atomically dispersed and it was coordinated with four pyridinic-N in Mg-NC.Due to the obvious electron transfer from Mg to its coordinated pyridinic-N,Mg–N_(4)active centers displayed high Lewis acid-base strength with abundant content,which brought remarkable catalytic activity.When Mg-NC was used for the TH of 5-hydroxymethylfurfural(HMF)in ethanol(EtOH),2,5-bis(hydroxymethyl)furan(BHMF)yield was up to 96.3%with high productivity of 19.85 molBHMF mol_(Mg)^(−1)h^(−1)at 150°C for 5 h.More interestingly,the process of TH over Mg-NC in EtOH was proved to proceed via the hydrogen radical mechanism.Additionally,Mg-NC exhibited powerful catalytic universality;it could not only utilize other primary alcohols(such as n-propanol and n-butanol)as hydrogen donors,but also catalyze the TH of other carbonyl compounds(such as furfural,5-methylfurfural,benzaldehyde,cyclohexanone,and levulinic acid).Overall,this work offered some important clues and references to reinforce the hydrogen-supplying ability of primary alcohols in the TH of various biomass-derived carbonyl compounds to high-value fine chemicals.
基金supported by Shaanxi Provincial Key Research and Development Project(No.2022ZDLSF06-08)Shaanxi Provincial Key Scientific and Technological Innovation Team,China(No.2023-CX-TD-32)+1 种基金the Key Scientific Research Projects of Education Department of Shaanxi Province,China(No.22JY035)the Project of Youth Talent Lift Program of Shaanxi Association for Science and Technology,China(No.20230447).
文摘In the conventional water treatment process,algae have a propensity to breach the filter barriers and potentially seep into the water distribution system,leading to an elevation in taste and odor compounds(T&O compounds).This investigation delved into the seasonal fluctuations of algae penetration and the production of T&O compounds within the treatment units of Reservoir Water Plant 1(W1)and River Water Plant 2(W2).The findings indicated that despite the application of the‘pre-oxidation,coagulation and sedimentation(PCS),sand filtration,and disinfection’process,certain robust-walled filamentous Cyanobacteria,Bacillariophyta species,and small Chlorophyta genera managed to bypass the filters.The leakage of algal cells during autumn at W1 was particularly striking,with a peak of 1,170,000 cells/L.The concurrent assessment of the potential for T&O compound formation revealed an alarming high potential for 2-methylisoborneol(2-MIB)in the water leaving the plants,with concentrations soaring to 197.20 ng/L at W1 in autumn and 54.78 ng/L at W2 in summer.This underscores the significant capacity of residual algal cells to generate T&O compounds.Tracking the retention and penetration dynamics of algal cells across each drinking water treatment stage is crucial for surface water treatment facilities to develop effective operational and management strategies,thereby enhancing the safety and quality of drinking water for the end consumer.
基金supported by the National Natural Science Foundation of China(Nos.41905108 and 42130704).
文摘Carbonyl compounds play a pivotal role in the formation of secondary pollutants such as O_(3) and SOA,signifi-cantly impacting air quality and human health.This study extended the observation period compared to previous research,providing a long-term perspective on carbonyl compound variations and their environmental implica-tions.Atmospheric observations were conducted at Beijing(BJ)and Xianghe(XH)during the summer and winter months of 2018,2019,and 2023 to study the sources and impacts of carbonyl compounds in typical urban areas and peri‑urban areas.Notably,concentrations in the summer of 2023 increased compared to 2018 and 2019.The predominant carbonyl compounds—formaldehyde,acetaldehyde,and acetone—accounted for over 60%of the total.The mean values of OFP in BJ ranged from 18.55 to 58.61μg/m3,lower than those in XH(29.82 to 65.48μg/m3),with formaldehyde and acetaldehyde contributing over 80%of the total.SOAP exhibited a similar pattern,with values in XH(69.21 to 508.55μg/m3)significantly exceeding those in BJ(34.47 to 159.78μg/m3).The PMF model highlighted vehicle exhaust,secondary pollution,and biomass combustion as major sources of carbonyl compounds,emphasizing differences in source contributions between the two regions.This study’s com-parative analysis over different years and locations provides new insights into the dynamic changes in carbonyl compounds and their environmental importance.These results not only reinforce the importance of carbonyl compounds regulation but also offer a valuable reference for evaluating and refining emission control strategies during this period.
基金Project supported by the National Key Research and Development Program of China(2021YFB3501204)the National Science Foundation for Excellent Young Scholars(52222107)+1 种基金CAS Project for Young Scientists in Basic Research(YSBR-057)the High-Level and High-Skilled Leading Talent Training Program of Jiangxi Province。
文摘The search for high-abundance compounds containing rare earth elements to develop high-performance magnetic refrigeration materials for hydrogen liquefaction has become a particularly attractive research direction.We successfully manipulated the magnetic interactions in tetragonal rare earth carbides(RE_(3)C_(4))by doping them with boron(B)element,transforming their state from antiferromagnetic to ferromagnetic.Theoretical calculations and experimental results indicate that the transition in magnetic interactions may be due to the synergistic effects of electronic structure and lattice distortions.Building on this,further doping with holmium(Ho)element was used to adjust the magnetic transition temperature of the system.The results show that the magnetic transition temperature of this series of compounds can be effectively altered within the range of 26-42.8 K.By optimizing the composition of rare earth elements,a series of novel candidate materials exhibiting significant magnetocaloric effects within the temperature range required for hydrogen liquefaction is successfully developed.
基金Supported by the Jiangsu Province’s Colleges and Universities(Integration of Chinese and Western Medicine)the National Natural Science Foundation of China[Methanism on Molecular and Hippocampus-Thalamus Neurocircuitry of Rapid Prokinetic and Antidepressant by Shugan Following Acute Stress(81973589)]The Relationship Between Stress,Ghrelin Signaling,Liver-Soothing and Antidepressant Prokinetic Mechanisms(81573797)。
文摘OBJECTIVE:To eliminate ineffective or interfering compounds from the eight absorbed compounds(8ACs),identify the primary ACs that represent the multifunctional therapeutic effects of Zhiqiao(Fructus Aurantii Submaturus)and Houpo(Cortex Magnoliae Officinalis)(FM),along with elucidating their underlying mechanisms.METHODS:Key multifunctional ACs were screened through ex vivo-to-in vitro extrapolation(ex vivo dose=serum concentration)and validated in vivo,with efficacy assessed via contribution(dose=FM content).Functional magnetic resonance imaging analyzed brain regions's blood oxygen level-dependent(BOLD)changes,and the molecular mechanisms were analyzed by transcriptome of the dentate gyrus(DG).RESULTS:The results showed that representative 2ACs(Nobiletin+Magnolol)and 3ACs(Nobiletin+Magnolol+Meranzin hydrate)screened on ex vivo experiment by the criteria of contribution ranking contributed 80.72%-126.74%of the antidepressant and prokinetic effects of the FM(improvement of depressive-like behaviours,gastrointestinal disorder,monoamine neurotransmitters,ghrelin,endocrine hormones,pro-inflammatory factors,oxidative stress indicators).In addition,3ACs demonstrated superiority over 2ACs in improving depression and levels of multiple stress mediators.Zhiqiao(Fructus Aurantii Submaturus)(FRA)reduced acute stress-induced hyperactivation of the cingulate cortex,thalamus,hypothalamus,and entorhinal cortex and elevated BOLD signaling in the insular cortex,temporal association cortex.Furthermore,FRA upregulated pathways of neurotransmitter receptor activity and serotonergic synaptic function and downregulated inflammation-related pathways at the genetic level.CONCLUSION:2ACs and 3ACs closely reflected FM's multifunctional effect in antidepressant and prokinetic.FRA restores stress-impaired neural connectivity in functional brain regions and improves synaptic plasticity and neurogenesis at the genetic level.
基金supported by the National Natural Science Foundation of China (No. 50979102, 40730528,40901252, 20907057)
文摘After the application of methionine, a progressive and significant increase occurred in five volatile organic sulfur compounds （VOSCs）： methanethiol （MESH）, dimethyl sulfide （DMS）, dime^yl disulfide （DMDS）, dimethyl trisulfide （DMTS） and dimethyl tetrasulfide （DMTeS）. Even in the untreated control without a methionine addition, methionine and its catabolites （VOSCs, mainly DMDS） were found in considerable amounts that were high enough to account for the water＇s offensive odor. However, blackening only occurred in two methionine-amended treatments. The VOSCs production was observed to precede black color development, and the reaching of a peak value for total VOSCs was often followed by water blackening. The presence of glucose stimulated the degradation of methionine while postponing the occurrence of the black color and inhibiting the production of VOSCs. In addition, DMDS was found to be the most abundant species produced after the addition of methionine alone, and DMTeS appeared to be the most important compound produced after the addition of methionine＋glucose. These results suggest that methionine acted as an important precursor of the VOSCs in lakes suffering from algea-induced black bloom. The existence of glucose may change the transformation pathway of methionine into VOSCs to form larger molecular weight compounds, such as DMTS and DMTeS.
基金supported by the Anhui Provincial Natural Science Foundation (Grant No.2508085J006)CASHIPS Director's Fund (Grant No.YZJJ202207-CX)。
文摘The zigzag nitrogen chain,similar to the Ch-N structure,has long been considered as a potential high-energy-density structure.However,all the previously predicted zigzag N-chain structures,similar to Ch-N,exhibited imaginary frequencies in their phonon spectra at 0 GPa.Here,we conducted a systematic investigation of P-N compounds using first-principles calculations,uncovering a series of structurally similar stable phases,C2/m-PN_(x)(x=6,8,10,12,and 14),in which N forms zigzag N chains similar to those in Ch-N.In P-N compounds,the longest zigzag N-chain,which can theoretically remain stable under ambient pressure,is the N-chain composed of 14 N atoms in C2/m-PN14.If the N-chain continues to grow,imaginary interchain vibrational frequencies arise in the system.Notably,N chains with an even number of atoms were more likely to be energetically favorable.The five C2/m-PN_(x) phases and one metastable phase(R-PN_(6))exhibited remarkable stability and excellent detonability at ambient pressure,indicating that they are promising candidates for high-energy-density materials.In addition,R-PN_(6) was the first structure to stabilize the N_(6) ring through covalent bonding,with the covalent network contributing to its high hardness(47.59 GPa).
基金Supported by the State Science Foundation of China (No. 20737001)
文摘Structural and thermodynamic parameters of 56 oxygen-containing and 56 sulfur- containing organic compounds were computed at the B3LPY/6-311G＊＊ level using density functional theory （DFT） method. Furthermore,the dependent equations between the experimental data of boiling points （Tb） and theoretical parameters were proposed with SPSS12.0 for windows software,whose correlation coefficients R2 are 0.933 and 0.945. These dependent equations were validated by cross-validation method （q2 are 0.923 and 0.929,respectively）. VIF （variance inflation factors） and t-value methods were also used to verify the significance and self-correlationship of each variable. Results indicate that our dependent equation exhibits good prediction ability,and molecular polarizability （α） is the main factor affecting the Tb of oxygen- and sulfur-containing organic compounds. To our interest,obvious dependence could also be found among the oxygen- and sulfur-containing organic compounds＇ experimental data of boiling points （Tb） with R^2 of 0.857.
文摘The role of the sulfur 3d orbitals in bond formation is discussed by taking into account the influence of the environment on the orbitals of the sulfur atom in the molecules. The ca cula- tion results of a series of prototype molecules containing sulfur such as SF_2, SF_4, NSF_3, SF_1, H_2S are reported. It is convincingly shown that in highly electronegative environment the energy levels of the sulfur 3d orbitals are reduced to the vicinity of those of the ligand valence orbitals and their spatial distributions are contracted to the bonding area, and therefore they can participate in bond formation to a certain extent, which is enhanced by the formation of the d-p π back bonds. It seems that the result reported in this paper is helpful for the solution of the long-standing debate about the sulfur 3d orbital participation in bond formation.
