Six coordination polymers based on 9,10-di(pyridine-4-yl)-anthracene(DPA)and 1,6-di(1H-imidazol-1-yl)pyrene(DIP)were obtained by solvothermal reactions.{[Zn(DPA)Cl_(2)]·DMF·2H_(2)O}n(1)and{[Zn_(1.5)(DPA)_(1....Six coordination polymers based on 9,10-di(pyridine-4-yl)-anthracene(DPA)and 1,6-di(1H-imidazol-1-yl)pyrene(DIP)were obtained by solvothermal reactions.{[Zn(DPA)Cl_(2)]·DMF·2H_(2)O}n(1)and{[Zn_(1.5)(DPA)_(1.5)Cl_(3)]·5H_(2)O}n(2)are framework isomers,which both contain zigzag chains formed by DPA,Zn^(2+),and Cl-.The zigzag chains in 1 are further assembled by C—H…Cl interactions into layers,and these layers exhibit two different orientations,displaying a rare 2D to 3D interpenetration mode.The zigzag chains in 2 are parallelly arranged.{[Zn_(3)(DPA)_(3)Br_(6)]·2DMF·_(1.5)H_(2)O}n(3)is isostructural to 2.3 was obtained using ZnBr_(2)instead of ZnCl_(2).[M(DPA)(formate)_(2)(H_(2)O)_(2)]n[M=Co(4),Cu(5)]are isostructural,contain chain structures formed by DPA,Cu^(2+)/Co^(2+),and for-mate ions,which were formed in situ in the solvothermal reaction.{[Zn(DIP)_(2)Cl]ClO_(4)}n(6)contains a layer structure formed by DIP and Zn^(2+).Free DPA and DIP ligands exhibited high fluorescence at room temperature,and coordina-tion polymers 3 and 6 displayed enhanced fluorescent emissions.展开更多
Fully utilizing renewable biomass energy is important for saving energy,reducing carbon emissions,and mitigating climate change.As the main hydrolysate of cellulose,a primary component of lignocellulose,glucose could ...Fully utilizing renewable biomass energy is important for saving energy,reducing carbon emissions,and mitigating climate change.As the main hydrolysate of cellulose,a primary component of lignocellulose,glucose could be employed as a starting material to prepare some other functional derivatives for improving the value of biomass resources.The isomerization of glucose to produce fructose is an important intermediate process during numerous high-value-added chemical preparations.Therefore,the development of efficient and selective catalysts for glucose isomerization is of great significance.Currently,glucose isomerase catalysts are limited by the harsh conditions required for microbial activity,which restricts further improvements in fructose yield.Additionally,heterogeneous Bronsted-base and Lewis-acid catalysts commonly employed in chemical isomerization methods often lead to the formation of undesirable by-products,resulting in reduced selectivity toward fructose.This study has demonstrated that lithium-loaded heterogeneous catalysts possess excellent isomerization capabilities under mild conditions.A highly efficient Li-C_(3)N_(4) catalyst was developed,achieving a fructose selectivity of 99.9% and a yield of 42.6% at 60℃ within 1.0 h-comparable to the performance of the enzymatic method.Characterization using X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD),proton nuclear magnetic resonance(^(1)H NMR),and inductively coupled plasma(ICP)analyses confirmed that lithium was stably incorporated into the g-C_(3)N_(4) framework through the formation of Li-N bonds.Further investigations using CO_(2) temperature-programmed desorption(CO_(2)-TPD),in situ Fourier-transform infrared spectroscopy(FT-IR)and 7Li magic angle spinning nuclear magnetic resonance(^(7)Li MAS NMR)indicated that the isomerization proceeded via a base-catalyzed mechanism.The Li species were found to interact with hydroxyl groups generated through hydrolysis and simultaneously coordinated with nitrogen atoms in the C_(3)N_(4) matrix,resulting in the formation of Li-N_(6)-H_(2)O active sites.These active sites facilitated the deprotonation of glucose to form an enolate intermediate,followed by a proton transfer step that generated fructose.This mechanism not only improved the efficiency of fructose production but also provided valuable insight into the catalytic role of lithium within the isomerization process.展开更多
Binuclear complexes have attracted extensive attention in fields such as catalysis because of their likely bimetallic synergistic effect;however,the mechanism and factors influencing this synergism remain unclear.In t...Binuclear complexes have attracted extensive attention in fields such as catalysis because of their likely bimetallic synergistic effect;however,the mechanism and factors influencing this synergism remain unclear.In this work,six bis-β-ketoimine binuclear titanium complexes4a-4f containing different alkylthio sidearms and configurations were synthesized and characterized by nuclear magnetic resonance hydrogen spectrum(~1H-NMR),nuclear magnetic resonance carbon spectrum(^(13)C-NMR),Fourier transform infrared spectrum(FTIR),and elemental analysis.The intermetallic distances of isomeric complexes 4a,4d,4e and 4f determined through density functional theory(DFT)optimization were in the order 4a<4d<4e<4f and were found to significantly influence the catalytic performance for ethylene(co)polymerization.These complexes could efficiently catalyze ethylene polymerization and ethylene/1-hexene or ethylene/1-octene copolymerization with high activity to produce highmolecular-weight ethylene homo-and co-polymers.Among the three binuclear titanium complexes 4a-4c with similar structures but different lengths of alkylthio sidearms,complex 4a,which contained the shortest methylthio sidearm,exhibited the highest activity for ethylene polymerization and copolymerization with 1-hexene or 1-octene.Additionally,for ethylene/1-hexene or ethylene/1-octene copolymerization,it showed the highest comonomer incorporation compared with propylthio(4b)and octylthio(4c)derivatives because of the smaller steric hindrance of the methyl group in 4a and the more open coordination space for vinyl monomers.Furthermore,among the isomeric complexes 4a,4d,4e and4f,complex 4a with the shortest bimetallic distance also exhibited the highest activity towards ethylene(co)polymerization,and the highest 1-hexene or 1-octene incorporation in comparison with its regioisomeric counterparts 4d,4e and p-phenyl-bridged analog 4f,owing to a more appropriate bimetallic distance that is conducive to a synergistic effect.展开更多
In this study,a pair of dicarboxylic acids as cis-trans isomerism—citraconic acid(CA)and mesaconic acid(MA),was incorporated into polymeric networks of poly(N-isopropylacrylamide)(PNIPAM)-based core-shell microgels v...In this study,a pair of dicarboxylic acids as cis-trans isomerism—citraconic acid(CA)and mesaconic acid(MA),was incorporated into polymeric networks of poly(N-isopropylacrylamide)(PNIPAM)-based core-shell microgels via semi-batch precipitation polymerization.We demonstrated that the pH-temperature dual responsiveness of the core-shell microgels is highly correlated with the structure and position of the acid isomers.Both the cis-trans molecular structure and the crosslinking position of the dicarboxylic acids significantly influenced the hydration capacity and surface charge density of the core-shell microgels.These diverse properties first influenced the swelling behavior,further affecting the interfacial behavior of the microgels,including the oil-water dynamic interfacial tension and air-water compression isotherms.Furthermore,the rheological behavior of the microgel suspensions also displayed distinct dependences on the frequency and temperature,illustrating that the cis-trans molecular structure and crosslinked position of the dicarboxylic acids also significantly influenced the interparticle clustering in the bulk solution.Our results suggest that the pH sensitivity of the cis-trans dicarboxylic acid isomer affects the ionization and surface charge distribution of the core or shell layers of individual microgels,which further determines the interparticle interaction and cooperative rearrangement at interfaces and in the bulk.展开更多
We propose a novel scheme for the population and depletion of nuclear isomers.This scheme combines the γ photons with energiesà 10 keV emitted during the interaction of a contemporary high-intensity laser pulse ...We propose a novel scheme for the population and depletion of nuclear isomers.This scheme combines the γ photons with energiesà 10 keV emitted during the interaction of a contemporary high-intensity laser pulse with a plasma and one or multiple photon beams supplied by intense lasers.Owing to nonlinear effects,two-or multiphoton absorption dominates over the conventional multistep one-photon process for an optimized γ flash.Moreover,this nonlinear effect can be greatly enhanced with the help of externally supplied low-energy photons coming from another laser.These low-energy photons act such that the effective cross-section experienced by the γ photons becomes tunable,growing with the intensity I_(0) of the beam.Assuming I_(0)~10^(18) W·cm^(-2) for the photon beam,an effective cross-section as large as 10^(-21)-10^(-28) cm^(2) for the γ photons can be achieved.Thus,with state-of-the-art 10 PW laser facilities,the yields from two-photon absorption can reach 10^(6)-10^(9) isomers per shot for selected states that are separated from their ground state by E2 transitions.Similar yields for transitions with higher multipolarities can be accommodated by multiphoton absorption with additional photons provided.展开更多
BACKGROUND Mac-2 binding protein glycosylation isomer(M2BPGi)serves as a marker of activated hepatic stellate cells and as such holds potential as a biomarker for liver fibrosis.In Viet Nam,metabolic dysfunction-assoc...BACKGROUND Mac-2 binding protein glycosylation isomer(M2BPGi)serves as a marker of activated hepatic stellate cells and as such holds potential as a biomarker for liver fibrosis.In Viet Nam,metabolic dysfunction-associated steatotic liver disease(MASLD)is rising in prevalence and there is an urgent need for better clinical management,particularly in early detection methods that will improve overall prognosis.AIM To examine M2BPGi cut-off values for staging liver fibrosis in patients with MASLD and risk factors associated with disease progression.METHODS A total of 301 individuals with ultrasound-confirmed or FibroScan-confirmed diagnosis of fatty liver were enrolled in the study.The participants were stratified according to fibrosis stage,measured via magnetic resonance elastography.M2-BPGi,Fibrosis-4(FIB-4)Index score,and routine parameters of liver function were assessed to statistically investigate the correlation of M2BPGi levels in various fibrosis stages and to identify risk factors associated with fibrosis severity.RESULTS M2BPGi levels positively correlated with fibrosis stages,with cut-off indexes of 0.57 for F0-1,0.68 for F2-3,and 0.78 for F4.M2BPGi levels in the F0-1 group were significantly different from those in both the F2-3 group(P=0.038)and the F4 group(P=0.0051);the F2-3 and F4 groups did not show a significant difference(P=0.39).Females exhibited significantly higher M2BPGi levels than males for all fibrosis stages,particularly in the F2-3 group(P=0.01)and F4 group(P=0.0006).In the F4(cirrhosis)group,individuals with diabetes had significantly higher M2BPGi levels than those without.M2BPGi,hemoglobin A1c,and FIB-4 score were identified as independent risk factors for greater fibrosis and cirrhosis.CONCLUSION M2BPGi levels varied significantly throughout fibrosis progression,from early MASLD to cirrhosis,with sex correlation.M2BPGi holds promise as an early biomarker for fibrosis characterization in MASLD adult patient populations.展开更多
Organic additives with multiple functional groups have shown great promise in improving the performance and stability of perovskite solar cells.The functional groups can passivate undercoordinated ions to reduce nonra...Organic additives with multiple functional groups have shown great promise in improving the performance and stability of perovskite solar cells.The functional groups can passivate undercoordinated ions to reduce nonradiative recombination losses.However,how these groups synergistically affect the enhancement beyond passivation is still unclear.Specifically,isomeric molecules with different substitution patterns or molecular shapes remain elusive in designing new organic additives.Here,we report two isomeric carbazolyl bisphosphonate additives,2,7-Cz BP and 3,6-Cz BP.The isomerism effect on passivation and charge transport process was studied.The two molecules have similar passivation effects through multiple interactions,e.g.,P=O···Pb,P=O···H–N and N–H···I.2,7-CzBP can further bridge the perovskite crystallites to facilitates charge transport.Power conversion efficiencies(PCEs)of 25.88%and 21.04%were achieved for 0.09 cm^(2)devices and 14 cm^(2)modules after 2,7-Cz BP treatment,respectively.The devices exhibited enhanced operational stability maintaining 95%of initial PCE after 1000 h of continuous maximum power point tracking.This study of isomerism effect hints at the importance of tuning substitution positions and molecular shapes for organic additives,which paves the way for innovation of next-generation multifunctional aromatic additives.展开更多
In recent years,the ternary strategy of adding a vip molecule to the active layer has been proven to be effective for improving the performance of organic solar cells(OSCs).Isomerization engineering of the vip mol...In recent years,the ternary strategy of adding a vip molecule to the active layer has been proven to be effective for improving the performance of organic solar cells(OSCs).Isomerization engineering of the vip molecule is a simple method to increase the amount of promising material,but there are only limited reports,and the structure-property relationships are still unclear.In this work,we synthesized three isomers named BTA5-F-o,BTA5-F-m,and BTA5-F-p,with different fluorine substitution positions,to study the influence of isomerization on the photovoltaic performance.After introducing them as the third components to the classic host system PM6:Y6,all three ternary devices showed improved power conversion efficiency(PCEs)compared to the binary system(PCE of 17.46%).The ternary OSCs based on BTA5-F-o achieved a champion PCE of 19.11%,while BTA5-F-m and BTA5-F-p realized PCEs of 18.65%and 18.45%,respectively.Mechanism studies have shown that the dipole moment of the BTA5-F-o end group is closer to that of the Y6 end group,despite the three isomers with almost identical energy levels and optical properties.It is indicated that the electron attraction ability of BTA5-F-o best matches that of Y6,which leads to the higher charge mobility,less charge recombination,and stronger exciton dissociation and extraction ability in the ternary blend system.This study suggests that rationally adjusting the position of substituents in the terminal group can be an effective way to construct nonfullerene vip acceptors to achieve highly efficient ternary OSCs.展开更多
As more and more studies have shown that lipid molecules play an important role in the whole biology,in-depth analysis of lipid structure has become particularly important in lipidomics.Mass spectrometry(MS),as the pr...As more and more studies have shown that lipid molecules play an important role in the whole biology,in-depth analysis of lipid structure has become particularly important in lipidomics.Mass spectrometry(MS),as the preferred tool for lipid analysis,has greatly promoted the development of this field.However,the existing MS methods still face many difficulties in the in-depth or even comprehensive analysis of lipid structure.In this review,we discuss recent advances in MS methods based on double bond-specific chemistries for the resolving of C=C location and geometry isomers of lipids.This progress has greatly advanced the lipidomics analysis to a deeper structural level and facilitated the development of structural lipid biology.展开更多
This study explores the phenomenon of shape coexistence in nuclei around^(172)Hg,with a focus on the isotopes^(170)Pt,^(172)Hg,and^(174)Pb,as well as the^(170)Pt to^(180)Pt isotopic chain.Utilizing a macro-microscopic...This study explores the phenomenon of shape coexistence in nuclei around^(172)Hg,with a focus on the isotopes^(170)Pt,^(172)Hg,and^(174)Pb,as well as the^(170)Pt to^(180)Pt isotopic chain.Utilizing a macro-microscopic approach that incorporates the Lublin-Strasbourg Drop model combined with a Yukawa-Folded potential and pairing corrections,we analyze the potential energy surfaces(PESs)to understand the impact of pairing interaction.For^(170)Pt,the PES exhibited a prolate ground state,with additional triaxial and oblate-shaped isomers.In^(172)Hg,the ground-state deformation transitions from triaxial to oblate with increasing pairing interaction,demonstrating its nearlyγ-unstable nature.Three shape isomers(prolate,triaxial,and oblate)were observed,with increased pairing strength leading to the disappearance of the triaxial isomer.^(174)Pb exhibited a prolate ground state that became increasingly spherical with stronger pairing.While shape isomers were present at lower pairing strengths,robust shape coexistence was not observed.For realistic pairing interaction,the ground-state shapes transitioned from prolate in^(170)Pt to a coexistence ofγ-unstable and oblate shapes in^(172)Hg,ultimately approaching spherical symmetry in^(174)Pb.A comparison between Exact and Bardeen-Cooper-Schrieffer(BCS)pairing demonstrated that BCS pairing tends to smooth out shape coexistence and reduce the depth of the shape isomer,leading to less pronounced deformation features.The PESs for even-even^(170)-180 Pt isotopes revealed significant shape evolution.^(170)Pt showed a prolate ground state,whereas^(172)Pt exhibited both triaxial and prolate shape coexistence.In^(174)Pt,the ground state was triaxial,coexisted with a prolate minimum.For^(176)Pt,aγ-unstable ground state coexists with a prolate minimum.By 178 Pt and 180Pt,a dominant prolate minimum emerged.These results highlight the role of shape coexistence andγ-instability in the evolution of nuclear structure,especially in the mid-shell region.These findings highlight the importance of pairing interactions in nuclear deformation and shape coexistence,providing insights into the structural evolution of mid-shell nuclei.展开更多
The process of deep hydrodesulfurization(HDS)in gasoline typically results in the saturation of olefins,leading to significant reductions in octane number.In this work,Y-supported Co(Ni)-Mo catalysts that with differe...The process of deep hydrodesulfurization(HDS)in gasoline typically results in the saturation of olefins,leading to significant reductions in octane number.In this work,Y-supported Co(Ni)-Mo catalysts that with different Ni-Co content were prepared by the incipient wetness impregnation method,the structure and properties were characterized and analyzed using HRTEM,XPS,H_(2)-TPR,and NH_(3)-TPD.The isomerization of 1-hexene and 1-octene as well as the HDS of thiophene were studied by using model FCC naphtha.The incorporation of Ni was found to enhance the number of MoS_(2) stacking layers,thereby improving the degree of sulfurization in Mo and subsequently increasing the desulfurization rate,with a maximum achieved desulfurization rate of 94.7%.When employing a Ni/Co ratio of 3:2,optimal synergy between Ni and Co is achieved,resulting in a greater presence of multi-layer stacked II-Co(Ni)MoS active phases.Additionally,appropriate Brønsted acidity levels are maintained to facilitate efficient olefin isomerization while preserving high HDS activity.As a result,the current isomerization yield stands at 58.2%(mass).These understandings shed light on the development of highly HDS and olefin isomerization catalysts.展开更多
Photoisomerization-induced phase change are important for co-harvesting the latent heat and isomerization energy of azobenzene molecules.Chemically optimizing heat output and energy delivery at alternating temperature...Photoisomerization-induced phase change are important for co-harvesting the latent heat and isomerization energy of azobenzene molecules.Chemically optimizing heat output and energy delivery at alternating temperatures are challenging because of the differences in crystallizability and isomerization.This article reports two series of asymmetrically alkyl-grafted azobenzene(Azo-g),with and without a methyl group,that have an optically triggered phase change.Three exothermic modes were designed to utilize crystallization enthalpy(△H_(c))and photothermal(isomerization)energy(△H_(p))at different temperatures determined by the crystallization.Azo-g has high heat output(275-303 J g^(-1))by synchronously releasing△H_(c)and△H_(p)over a wide temperature range(-79℃to 25℃).We fabricated a new distributed energy utilization and delivery system to realize a temperature increase of 6.6℃at a temperature of-8℃.The findings offer insight into selective utilization of latent heat and isomerization energy by molecular optimization of crystallization and isomerization processes.展开更多
Efficient and selective glucose-to-fructose isomerization is a crucial step for production of oxygenated chemicals derived from sugars,which is usually catalyzed by base or Lewis acid heterogeneous catalyst.However,hi...Efficient and selective glucose-to-fructose isomerization is a crucial step for production of oxygenated chemicals derived from sugars,which is usually catalyzed by base or Lewis acid heterogeneous catalyst.However,high yield and selectivity of fructose cannot be simultaneously obtained under mild conditions which hamper the scale of application compared with enzymatic catalysis.Herein,a Li-promoted C_(3)N_(4) catalyst was exploited which afforded an excellent fructose yield(40.3 wt%)and selectivity(99.5%)from glucose in water at 50℃,attributed to the formation of stable Li–N bond to strengthen the basic sites of catalysts.Furthermore,the so-formed N_(6)–Li–H_(2)O active site on Li–C_(3)N_(4) catalyst in aqueous phase changes the local electronic structure and strengthens the deprotonation process during glucose isomerization into fructose.The superior catalytic performance which is comparable to biological pathway suggests promising applications of lithium containing heterogeneous catalyst in biomass refinery.展开更多
Photodegradation technology has been widely applied in the purification of industrial aromatic hydrocarbons.However,whether this technology efficiently removes the pollutants to prevent secondary pollution and health ...Photodegradation technology has been widely applied in the purification of industrial aromatic hydrocarbons.However,whether this technology efficiently removes the pollutants to prevent secondary pollution and health risk is still unclear.Here,the photodegradation processes of three xylenes were compared under designed reaction atmospheres and light sources.Xe lamp showed poor photodegradation ability toward xylenes,no matter in N_(2) or N_(2)+O_(2)system,while much higher photodegradation performance of xylenes were obtained under ultraviolet(UV)and vacuum ultraviolet(VUV)irradiation,especially in N_(2)+O_(2)+VUV system,where 97.9%of m-xylene,99.0%of o-xylene or 87.5%of p-xylene with the initial concentration of 860 mg/m^(3) was removed within 240 min.The xylenes underwent three processes of photo-isomerization,photodecomposition and photo-oxidation to produce intermediates of aromatics,alkanes and carbonyls.Among them,the photo-isomerization products showed the highest concentration percentage(e.g.,≥50%in o-xylene system),confirming that photo-isomerization reaction was the dominated photodegradation process of xylenes.Moreover,these isomerized products not only contributed about 97%and91%to the formation potential of O3(OFP)and secondary organic aerosols(SOAFP),but also displayed obvious non-carcinogenic risk,although one of photodecomposition product—benzene showed the highest occupational exposure risk.Therefore,the secondary pollution and health risks of photodegradation products of xylenes were non-ignorable,although the OFP,SOAFP and health risks of the generated products reduced at least 4.5 times in comparison with that of the degraded xylenes.The findings are helpful for the appropriate application of this technology in the purification of industrial organic waste gas.展开更多
An efficient and E-selective monoisomerization of 1-alkenes is developed with a bis(phosphine)-based PCP-type Co complex as the catalyst.The protocol provides an atom-economical approach to trans-2-alkenes with high r...An efficient and E-selective monoisomerization of 1-alkenes is developed with a bis(phosphine)-based PCP-type Co complex as the catalyst.The protocol provides an atom-economical approach to trans-2-alkenes with high regio-and stereoselectivity,featuring mild conditions and wide substrate scope.Mechanistic investigation supports a cobalt-hydride pathway involving reversible alkene insertion/β-H elimination,and the step ofβ-H elimination at the allylic position is likely the rate-determining step.展开更多
Acetylacetone(AcAc)is a typical class ofβ-diketones with broad industrial applications due to the property of the keto-enol isomers,but its isomerization and chemical reactions at the air-droplet interface are still ...Acetylacetone(AcAc)is a typical class ofβ-diketones with broad industrial applications due to the property of the keto-enol isomers,but its isomerization and chemical reactions at the air-droplet interface are still unclear.Hence,using combined molecular dynamics and quantum chemistry methods,the heterogeneous chemistry of AcAc at the air-droplet interface was investigated,including the attraction of AcAc isomers by the droplets,the distribution of isomers at the air-droplet interface,and the hydration reactions of isomers at the air-droplet interface.The results reveal that the preferential orientation of two AcAc isomers(keto-and enol-AcAc)to accumulate and accommodate at the acidic air-droplet interface.The isomerization of two AcAc isomers at the acidic air-droplet interface is more favorable than that at the neutral air-droplet interface because the“water bridge”structure is destroyed by H_(3)O^(+),especially for the isomerization from keto-Ac Ac to enol-AcAc.At the acidic air-droplet interface,the carbonyl or hydroxyl O-atoms of two AcAc isomers display an energetical preference to hydration.Keto-diol is the dominant products to accumulate at the air-droplet interface,and excessive keto-diol can enter the droplet interior to engage in the oligomerization.The photooxidation reaction of AcAc will increase the acidity of the air-droplet interface,which indirectly facilitate the uptake and formation of more keto-diol.Our results provide an insight into the heterogeneous chemistry ofβ-diketones and their influence on the environment.展开更多
Organic electrode materials are promising for batteries.However,the reported organic electrodes are often facing the challenges of low specific capacity,low voltage,poor rate capability and vague charge storage mechan...Organic electrode materials are promising for batteries.However,the reported organic electrodes are often facing the challenges of low specific capacity,low voltage,poor rate capability and vague charge storage mechanisms,etc.Isomers are good platform to investigate the charge storage mechanisms and enhance the performance of batteries,which,however,have not been focused in batteries.Herein,two isomers are reported for batteries.As a result,the isomer tetrathiafulvalene(TTF)could store two monovalent anions reversibly,deriving an average discharge voltage of 1.05 V and a specific capacity of 220 mAh g−1 at a current density of 2 C.On the other hand,the other isomer tetrathianaphthalene could only reversibly store one monovalent anion and upon further oxidation,it would undergo an irreversible solid-state molecular rearrangement to TTF.The molecular rearrangement was confirmed by electrochemical performances,X-ray diffraction patterns,nuclear magnetic resonance spectra,and 1H detected heteronuclear multiple bond correlation spectra.These results suggested the small structural change could lead to a big difference in anion storage,and we hope this work will stimulate more attention to the structural design for boosting the performance of organic batteries.展开更多
Isomerization of glucose to fructose is a fundamental and key intermediate process commonly included in the production of valuable chemicals from carbohydrates in biorefinery.Enhancement of fructose yield is a challen...Isomerization of glucose to fructose is a fundamental and key intermediate process commonly included in the production of valuable chemicals from carbohydrates in biorefinery.Enhancement of fructose yield is a challenge.In this work,Sn-doped silica nanotube(Sn-SNT)was developed as a highly efficient Lewis acid catalyst for the selective isomerization of glucose to fructose.Over Sn-SNT,69.1%fructose yield with 78.5%selectivity was obtained after reaction at 110◦C for 6 h.The sole presence of a large amount of Lewis acid sites in Sn-SNT without Brønsted acid site is one of the reasons for the high fructose yield and selectivity.Otherwise,high density of SiOH groups in Sn-SNT can ensure the presence of SiOH groups near the Sn sites,which is important for the isomerization of glucose to fructose,leading to the high fructose yield and selectivity.Furthermore,the Sn-SNT is recyclable.展开更多
Azulene is a promising building block for creating innovative polycyclic aromatic hydrocarbons. This study involved the construction of three nonalternant isomers of pentacene by fusing two azulene units, named Az-PH1...Azulene is a promising building block for creating innovative polycyclic aromatic hydrocarbons. This study involved the construction of three nonalternant isomers of pentacene by fusing two azulene units, named Az-PH1/2/3. Az-PH1 was initially developed through the rhodium(Ⅱ)-catalyzed cyclization of bis(N-tosylhydrazone)s. Intriguingly, Az-PH1 was also unexpectedly obtained during a nickel(0)-catalyzed one-step tandem reaction. We investigated the optical and electrochemical properties, aromaticity, and photo-oxidative stability of Az-PH1, comparing it with the well-known pentacene using density functional theory, electrochemical, and photophysical tests. Our results showed that the azulene-fusing strategy resulted in a molecule with narrow optical bandgaps(2.046 eV) and a long half-life time under ambient air conditions.展开更多
The transformation of aldose to ketose or common sugars into rare saccharides,including rare ketoses and aldoses,is of great value and interest to the food industry and for saccharidic biomass utilization,medicine,and...The transformation of aldose to ketose or common sugars into rare saccharides,including rare ketoses and aldoses,is of great value and interest to the food industry and for saccharidic biomass utilization,medicine,and the synthesis of drugs.Nowadays,high-fructose corn syrup(HFCS)is industrially produced in more than 10 million tons annually using immobilized glucose isomerase.Some low-calorie saccharides such as tagatose and psicose,which are becoming popular sweeteners,have also been produced on a pilot scale in order to replace sucrose and HFCS.However,current catalysts and catalytic processes are still difficult to utilize in biomass conversion and also have strong substrate dependence in producing high-value,rare sugars.Considering the specific reaction properties of saccharides and catalysts,since the pioneering discovery by Fischer,various catalysts and catalytic systems have been discovered or developed in attempts to extend the reaction pathways,improve the reaction efficiency,and to potentially produce commercial products.In this review,we trace the history of sugar isomerization/epimerization reactions and summarize the important breakthroughs for each reaction as well as the difficulties that remain unresolved to date.展开更多
文摘Six coordination polymers based on 9,10-di(pyridine-4-yl)-anthracene(DPA)and 1,6-di(1H-imidazol-1-yl)pyrene(DIP)were obtained by solvothermal reactions.{[Zn(DPA)Cl_(2)]·DMF·2H_(2)O}n(1)and{[Zn_(1.5)(DPA)_(1.5)Cl_(3)]·5H_(2)O}n(2)are framework isomers,which both contain zigzag chains formed by DPA,Zn^(2+),and Cl-.The zigzag chains in 1 are further assembled by C—H…Cl interactions into layers,and these layers exhibit two different orientations,displaying a rare 2D to 3D interpenetration mode.The zigzag chains in 2 are parallelly arranged.{[Zn_(3)(DPA)_(3)Br_(6)]·2DMF·_(1.5)H_(2)O}n(3)is isostructural to 2.3 was obtained using ZnBr_(2)instead of ZnCl_(2).[M(DPA)(formate)_(2)(H_(2)O)_(2)]n[M=Co(4),Cu(5)]are isostructural,contain chain structures formed by DPA,Cu^(2+)/Co^(2+),and for-mate ions,which were formed in situ in the solvothermal reaction.{[Zn(DIP)_(2)Cl]ClO_(4)}n(6)contains a layer structure formed by DIP and Zn^(2+).Free DPA and DIP ligands exhibited high fluorescence at room temperature,and coordina-tion polymers 3 and 6 displayed enhanced fluorescent emissions.
基金supported by the National Natural Science Foundation of China(22278419)the Key Core Technology Research(Social Development)Foundation of Suzhou(2023ss06)the Suzhou National Joint Laboratory for Green and Low-carbon Wastewater Treatment and Resource Utilization Technology,Suzhou University of Science and Technology(SZLSDT202404).
文摘Fully utilizing renewable biomass energy is important for saving energy,reducing carbon emissions,and mitigating climate change.As the main hydrolysate of cellulose,a primary component of lignocellulose,glucose could be employed as a starting material to prepare some other functional derivatives for improving the value of biomass resources.The isomerization of glucose to produce fructose is an important intermediate process during numerous high-value-added chemical preparations.Therefore,the development of efficient and selective catalysts for glucose isomerization is of great significance.Currently,glucose isomerase catalysts are limited by the harsh conditions required for microbial activity,which restricts further improvements in fructose yield.Additionally,heterogeneous Bronsted-base and Lewis-acid catalysts commonly employed in chemical isomerization methods often lead to the formation of undesirable by-products,resulting in reduced selectivity toward fructose.This study has demonstrated that lithium-loaded heterogeneous catalysts possess excellent isomerization capabilities under mild conditions.A highly efficient Li-C_(3)N_(4) catalyst was developed,achieving a fructose selectivity of 99.9% and a yield of 42.6% at 60℃ within 1.0 h-comparable to the performance of the enzymatic method.Characterization using X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD),proton nuclear magnetic resonance(^(1)H NMR),and inductively coupled plasma(ICP)analyses confirmed that lithium was stably incorporated into the g-C_(3)N_(4) framework through the formation of Li-N bonds.Further investigations using CO_(2) temperature-programmed desorption(CO_(2)-TPD),in situ Fourier-transform infrared spectroscopy(FT-IR)and 7Li magic angle spinning nuclear magnetic resonance(^(7)Li MAS NMR)indicated that the isomerization proceeded via a base-catalyzed mechanism.The Li species were found to interact with hydroxyl groups generated through hydrolysis and simultaneously coordinated with nitrogen atoms in the C_(3)N_(4) matrix,resulting in the formation of Li-N_(6)-H_(2)O active sites.These active sites facilitated the deprotonation of glucose to form an enolate intermediate,followed by a proton transfer step that generated fructose.This mechanism not only improved the efficiency of fructose production but also provided valuable insight into the catalytic role of lithium within the isomerization process.
基金financially supported by the National Natural Science Foundation of China(No.21172269)the Fundamental Research Funds for the Central Universities,SouthCentral Minzu University(No.CZH24005)。
文摘Binuclear complexes have attracted extensive attention in fields such as catalysis because of their likely bimetallic synergistic effect;however,the mechanism and factors influencing this synergism remain unclear.In this work,six bis-β-ketoimine binuclear titanium complexes4a-4f containing different alkylthio sidearms and configurations were synthesized and characterized by nuclear magnetic resonance hydrogen spectrum(~1H-NMR),nuclear magnetic resonance carbon spectrum(^(13)C-NMR),Fourier transform infrared spectrum(FTIR),and elemental analysis.The intermetallic distances of isomeric complexes 4a,4d,4e and 4f determined through density functional theory(DFT)optimization were in the order 4a<4d<4e<4f and were found to significantly influence the catalytic performance for ethylene(co)polymerization.These complexes could efficiently catalyze ethylene polymerization and ethylene/1-hexene or ethylene/1-octene copolymerization with high activity to produce highmolecular-weight ethylene homo-and co-polymers.Among the three binuclear titanium complexes 4a-4c with similar structures but different lengths of alkylthio sidearms,complex 4a,which contained the shortest methylthio sidearm,exhibited the highest activity for ethylene polymerization and copolymerization with 1-hexene or 1-octene.Additionally,for ethylene/1-hexene or ethylene/1-octene copolymerization,it showed the highest comonomer incorporation compared with propylthio(4b)and octylthio(4c)derivatives because of the smaller steric hindrance of the methyl group in 4a and the more open coordination space for vinyl monomers.Furthermore,among the isomeric complexes 4a,4d,4e and4f,complex 4a with the shortest bimetallic distance also exhibited the highest activity towards ethylene(co)polymerization,and the highest 1-hexene or 1-octene incorporation in comparison with its regioisomeric counterparts 4d,4e and p-phenyl-bridged analog 4f,owing to a more appropriate bimetallic distance that is conducive to a synergistic effect.
基金financially supported by the National Natural Science Foundation of China(No.22303033)the Fundamental Research Funds for the Central Universities,China(No.JUSRP123017)+1 种基金Wuxi“Taihu Light”Science and Technology Project-Basic Research(No.K20231063)the Research Matching Grant Scheme at CUHK(No.8601309)。
文摘In this study,a pair of dicarboxylic acids as cis-trans isomerism—citraconic acid(CA)and mesaconic acid(MA),was incorporated into polymeric networks of poly(N-isopropylacrylamide)(PNIPAM)-based core-shell microgels via semi-batch precipitation polymerization.We demonstrated that the pH-temperature dual responsiveness of the core-shell microgels is highly correlated with the structure and position of the acid isomers.Both the cis-trans molecular structure and the crosslinking position of the dicarboxylic acids significantly influenced the hydration capacity and surface charge density of the core-shell microgels.These diverse properties first influenced the swelling behavior,further affecting the interfacial behavior of the microgels,including the oil-water dynamic interfacial tension and air-water compression isotherms.Furthermore,the rheological behavior of the microgel suspensions also displayed distinct dependences on the frequency and temperature,illustrating that the cis-trans molecular structure and crosslinked position of the dicarboxylic acids also significantly influenced the interparticle clustering in the bulk solution.Our results suggest that the pH sensitivity of the cis-trans dicarboxylic acid isomer affects the ionization and surface charge distribution of the core or shell layers of individual microgels,which further determines the interparticle interaction and cooperative rearrangement at interfaces and in the bulk.
基金supported by the Extreme Light Infrastructure Nuclear Physics(ELI-NP)Phase Ⅱ,a project co-financed by the Romanian Government and the European Union through the European Regional Development Fund—the Competitiveness Operational Programme(1/07.07.2016,COP,ID 1334)the Romanian Ministry of Research and Innovation:PN23210105(Phase 2,the Program Nucleu),ELI-RO grants Proiectul ELI-RO/RDI_2024_AMAP,ELI-RO_RDI_2024_LaLuThe,ELIRO_RDI_2024_SPARC+4 种基金ELI10/01.10.2020 of the Romanian Governmentthe European Union,the Romanian Governmentthe Health Program,within the project“Medical Applications of High-Power Lasers—Dr.LASER”SMIS Code:326475the IOSIN funds for research infrastructures of national interest.
文摘We propose a novel scheme for the population and depletion of nuclear isomers.This scheme combines the γ photons with energiesà 10 keV emitted during the interaction of a contemporary high-intensity laser pulse with a plasma and one or multiple photon beams supplied by intense lasers.Owing to nonlinear effects,two-or multiphoton absorption dominates over the conventional multistep one-photon process for an optimized γ flash.Moreover,this nonlinear effect can be greatly enhanced with the help of externally supplied low-energy photons coming from another laser.These low-energy photons act such that the effective cross-section experienced by the γ photons becomes tunable,growing with the intensity I_(0) of the beam.Assuming I_(0)~10^(18) W·cm^(-2) for the photon beam,an effective cross-section as large as 10^(-21)-10^(-28) cm^(2) for the γ photons can be achieved.Thus,with state-of-the-art 10 PW laser facilities,the yields from two-photon absorption can reach 10^(6)-10^(9) isomers per shot for selected states that are separated from their ground state by E2 transitions.Similar yields for transitions with higher multipolarities can be accommodated by multiphoton absorption with additional photons provided.
文摘BACKGROUND Mac-2 binding protein glycosylation isomer(M2BPGi)serves as a marker of activated hepatic stellate cells and as such holds potential as a biomarker for liver fibrosis.In Viet Nam,metabolic dysfunction-associated steatotic liver disease(MASLD)is rising in prevalence and there is an urgent need for better clinical management,particularly in early detection methods that will improve overall prognosis.AIM To examine M2BPGi cut-off values for staging liver fibrosis in patients with MASLD and risk factors associated with disease progression.METHODS A total of 301 individuals with ultrasound-confirmed or FibroScan-confirmed diagnosis of fatty liver were enrolled in the study.The participants were stratified according to fibrosis stage,measured via magnetic resonance elastography.M2-BPGi,Fibrosis-4(FIB-4)Index score,and routine parameters of liver function were assessed to statistically investigate the correlation of M2BPGi levels in various fibrosis stages and to identify risk factors associated with fibrosis severity.RESULTS M2BPGi levels positively correlated with fibrosis stages,with cut-off indexes of 0.57 for F0-1,0.68 for F2-3,and 0.78 for F4.M2BPGi levels in the F0-1 group were significantly different from those in both the F2-3 group(P=0.038)and the F4 group(P=0.0051);the F2-3 and F4 groups did not show a significant difference(P=0.39).Females exhibited significantly higher M2BPGi levels than males for all fibrosis stages,particularly in the F2-3 group(P=0.01)and F4 group(P=0.0006).In the F4(cirrhosis)group,individuals with diabetes had significantly higher M2BPGi levels than those without.M2BPGi,hemoglobin A1c,and FIB-4 score were identified as independent risk factors for greater fibrosis and cirrhosis.CONCLUSION M2BPGi levels varied significantly throughout fibrosis progression,from early MASLD to cirrhosis,with sex correlation.M2BPGi holds promise as an early biomarker for fibrosis characterization in MASLD adult patient populations.
基金financially supported by the National Science Foundation of China(62474142)Natural Science Foundation of Shandong Province(No.ZR2024YQ070)。
文摘Organic additives with multiple functional groups have shown great promise in improving the performance and stability of perovskite solar cells.The functional groups can passivate undercoordinated ions to reduce nonradiative recombination losses.However,how these groups synergistically affect the enhancement beyond passivation is still unclear.Specifically,isomeric molecules with different substitution patterns or molecular shapes remain elusive in designing new organic additives.Here,we report two isomeric carbazolyl bisphosphonate additives,2,7-Cz BP and 3,6-Cz BP.The isomerism effect on passivation and charge transport process was studied.The two molecules have similar passivation effects through multiple interactions,e.g.,P=O···Pb,P=O···H–N and N–H···I.2,7-CzBP can further bridge the perovskite crystallites to facilitates charge transport.Power conversion efficiencies(PCEs)of 25.88%and 21.04%were achieved for 0.09 cm^(2)devices and 14 cm^(2)modules after 2,7-Cz BP treatment,respectively.The devices exhibited enhanced operational stability maintaining 95%of initial PCE after 1000 h of continuous maximum power point tracking.This study of isomerism effect hints at the importance of tuning substitution positions and molecular shapes for organic additives,which paves the way for innovation of next-generation multifunctional aromatic additives.
基金support from the National Natural Science Foundation of China(62204146,52303259)the Start-up Grant of Henan University of Technology(2023BS035)。
文摘In recent years,the ternary strategy of adding a vip molecule to the active layer has been proven to be effective for improving the performance of organic solar cells(OSCs).Isomerization engineering of the vip molecule is a simple method to increase the amount of promising material,but there are only limited reports,and the structure-property relationships are still unclear.In this work,we synthesized three isomers named BTA5-F-o,BTA5-F-m,and BTA5-F-p,with different fluorine substitution positions,to study the influence of isomerization on the photovoltaic performance.After introducing them as the third components to the classic host system PM6:Y6,all three ternary devices showed improved power conversion efficiency(PCEs)compared to the binary system(PCE of 17.46%).The ternary OSCs based on BTA5-F-o achieved a champion PCE of 19.11%,while BTA5-F-m and BTA5-F-p realized PCEs of 18.65%and 18.45%,respectively.Mechanism studies have shown that the dipole moment of the BTA5-F-o end group is closer to that of the Y6 end group,despite the three isomers with almost identical energy levels and optical properties.It is indicated that the electron attraction ability of BTA5-F-o best matches that of Y6,which leads to the higher charge mobility,less charge recombination,and stronger exciton dissociation and extraction ability in the ternary blend system.This study suggests that rationally adjusting the position of substituents in the terminal group can be an effective way to construct nonfullerene vip acceptors to achieve highly efficient ternary OSCs.
基金financially supported by the National Natural Science Foundation of China(No.22074111)National Key Research and Development Program of China(No.2021YFC2700700)the Opening fund of Hubei Key Laboratory of Bioinorganic Chemistry&Materia Medica(No.BCMM202303)。
文摘As more and more studies have shown that lipid molecules play an important role in the whole biology,in-depth analysis of lipid structure has become particularly important in lipidomics.Mass spectrometry(MS),as the preferred tool for lipid analysis,has greatly promoted the development of this field.However,the existing MS methods still face many difficulties in the in-depth or even comprehensive analysis of lipid structure.In this review,we discuss recent advances in MS methods based on double bond-specific chemistries for the resolving of C=C location and geometry isomers of lipids.This progress has greatly advanced the lipidomics analysis to a deeper structural level and facilitated the development of structural lipid biology.
基金supported by the National Natural Science Foundation of China(Nos.12275115 and 12175097)the National Science Centre of Poland(No.2023/49/B/ST2/01294).
文摘This study explores the phenomenon of shape coexistence in nuclei around^(172)Hg,with a focus on the isotopes^(170)Pt,^(172)Hg,and^(174)Pb,as well as the^(170)Pt to^(180)Pt isotopic chain.Utilizing a macro-microscopic approach that incorporates the Lublin-Strasbourg Drop model combined with a Yukawa-Folded potential and pairing corrections,we analyze the potential energy surfaces(PESs)to understand the impact of pairing interaction.For^(170)Pt,the PES exhibited a prolate ground state,with additional triaxial and oblate-shaped isomers.In^(172)Hg,the ground-state deformation transitions from triaxial to oblate with increasing pairing interaction,demonstrating its nearlyγ-unstable nature.Three shape isomers(prolate,triaxial,and oblate)were observed,with increased pairing strength leading to the disappearance of the triaxial isomer.^(174)Pb exhibited a prolate ground state that became increasingly spherical with stronger pairing.While shape isomers were present at lower pairing strengths,robust shape coexistence was not observed.For realistic pairing interaction,the ground-state shapes transitioned from prolate in^(170)Pt to a coexistence ofγ-unstable and oblate shapes in^(172)Hg,ultimately approaching spherical symmetry in^(174)Pb.A comparison between Exact and Bardeen-Cooper-Schrieffer(BCS)pairing demonstrated that BCS pairing tends to smooth out shape coexistence and reduce the depth of the shape isomer,leading to less pronounced deformation features.The PESs for even-even^(170)-180 Pt isotopes revealed significant shape evolution.^(170)Pt showed a prolate ground state,whereas^(172)Pt exhibited both triaxial and prolate shape coexistence.In^(174)Pt,the ground state was triaxial,coexisted with a prolate minimum.For^(176)Pt,aγ-unstable ground state coexists with a prolate minimum.By 178 Pt and 180Pt,a dominant prolate minimum emerged.These results highlight the role of shape coexistence andγ-instability in the evolution of nuclear structure,especially in the mid-shell region.These findings highlight the importance of pairing interactions in nuclear deformation and shape coexistence,providing insights into the structural evolution of mid-shell nuclei.
基金supported by the National Natural Science Foundation of China(U22B20140,22021004,22325808,22393950)the National Key Research and Development Program of China(2020YFA0210900).
文摘The process of deep hydrodesulfurization(HDS)in gasoline typically results in the saturation of olefins,leading to significant reductions in octane number.In this work,Y-supported Co(Ni)-Mo catalysts that with different Ni-Co content were prepared by the incipient wetness impregnation method,the structure and properties were characterized and analyzed using HRTEM,XPS,H_(2)-TPR,and NH_(3)-TPD.The isomerization of 1-hexene and 1-octene as well as the HDS of thiophene were studied by using model FCC naphtha.The incorporation of Ni was found to enhance the number of MoS_(2) stacking layers,thereby improving the degree of sulfurization in Mo and subsequently increasing the desulfurization rate,with a maximum achieved desulfurization rate of 94.7%.When employing a Ni/Co ratio of 3:2,optimal synergy between Ni and Co is achieved,resulting in a greater presence of multi-layer stacked II-Co(Ni)MoS active phases.Additionally,appropriate Brønsted acidity levels are maintained to facilitate efficient olefin isomerization while preserving high HDS activity.As a result,the current isomerization yield stands at 58.2%(mass).These understandings shed light on the development of highly HDS and olefin isomerization catalysts.
基金financially supported by National Key R&D Program of China(No.2022YFB3805702)the State Key Program of National Natural Science Foundation of China(No.52130303)
文摘Photoisomerization-induced phase change are important for co-harvesting the latent heat and isomerization energy of azobenzene molecules.Chemically optimizing heat output and energy delivery at alternating temperatures are challenging because of the differences in crystallizability and isomerization.This article reports two series of asymmetrically alkyl-grafted azobenzene(Azo-g),with and without a methyl group,that have an optically triggered phase change.Three exothermic modes were designed to utilize crystallization enthalpy(△H_(c))and photothermal(isomerization)energy(△H_(p))at different temperatures determined by the crystallization.Azo-g has high heat output(275-303 J g^(-1))by synchronously releasing△H_(c)and△H_(p)over a wide temperature range(-79℃to 25℃).We fabricated a new distributed energy utilization and delivery system to realize a temperature increase of 6.6℃at a temperature of-8℃.The findings offer insight into selective utilization of latent heat and isomerization energy by molecular optimization of crystallization and isomerization processes.
基金The financial support from the National Natural Science Foundation of China(22278419,21978316,22108289,22172188)the Ministry of Science and Technology of China(2018YFB0604700)Suzhou Key Technology Research(Social Development)Project(2023ss06)。
文摘Efficient and selective glucose-to-fructose isomerization is a crucial step for production of oxygenated chemicals derived from sugars,which is usually catalyzed by base or Lewis acid heterogeneous catalyst.However,high yield and selectivity of fructose cannot be simultaneously obtained under mild conditions which hamper the scale of application compared with enzymatic catalysis.Herein,a Li-promoted C_(3)N_(4) catalyst was exploited which afforded an excellent fructose yield(40.3 wt%)and selectivity(99.5%)from glucose in water at 50℃,attributed to the formation of stable Li–N bond to strengthen the basic sites of catalysts.Furthermore,the so-formed N_(6)–Li–H_(2)O active site on Li–C_(3)N_(4) catalyst in aqueous phase changes the local electronic structure and strengthens the deprotonation process during glucose isomerization into fructose.The superior catalytic performance which is comparable to biological pathway suggests promising applications of lithium containing heterogeneous catalyst in biomass refinery.
基金supported by the National Natural Science Foundation of China (Nos.42177354 and 21777032)the National Key R&D Program of China (No.2019YFC0214402)the Guangdong Basic and Applied Basic Research oundation (No.2019B151502064)。
文摘Photodegradation technology has been widely applied in the purification of industrial aromatic hydrocarbons.However,whether this technology efficiently removes the pollutants to prevent secondary pollution and health risk is still unclear.Here,the photodegradation processes of three xylenes were compared under designed reaction atmospheres and light sources.Xe lamp showed poor photodegradation ability toward xylenes,no matter in N_(2) or N_(2)+O_(2)system,while much higher photodegradation performance of xylenes were obtained under ultraviolet(UV)and vacuum ultraviolet(VUV)irradiation,especially in N_(2)+O_(2)+VUV system,where 97.9%of m-xylene,99.0%of o-xylene or 87.5%of p-xylene with the initial concentration of 860 mg/m^(3) was removed within 240 min.The xylenes underwent three processes of photo-isomerization,photodecomposition and photo-oxidation to produce intermediates of aromatics,alkanes and carbonyls.Among them,the photo-isomerization products showed the highest concentration percentage(e.g.,≥50%in o-xylene system),confirming that photo-isomerization reaction was the dominated photodegradation process of xylenes.Moreover,these isomerized products not only contributed about 97%and91%to the formation potential of O3(OFP)and secondary organic aerosols(SOAFP),but also displayed obvious non-carcinogenic risk,although one of photodecomposition product—benzene showed the highest occupational exposure risk.Therefore,the secondary pollution and health risks of photodegradation products of xylenes were non-ignorable,although the OFP,SOAFP and health risks of the generated products reduced at least 4.5 times in comparison with that of the degraded xylenes.The findings are helpful for the appropriate application of this technology in the purification of industrial organic waste gas.
文摘An efficient and E-selective monoisomerization of 1-alkenes is developed with a bis(phosphine)-based PCP-type Co complex as the catalyst.The protocol provides an atom-economical approach to trans-2-alkenes with high regio-and stereoselectivity,featuring mild conditions and wide substrate scope.Mechanistic investigation supports a cobalt-hydride pathway involving reversible alkene insertion/β-H elimination,and the step ofβ-H elimination at the allylic position is likely the rate-determining step.
基金supported by the Guangdong Basic and Applied Basic Research Foundation(No.2019B151502064)the National Natural Science Foundation of China(Nos.42077189,42020104001,and 42277081)+3 种基金the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2017BT01Z032)the Science and Technology Key Project of Guangdong ProvinceChina(No.2019B110206002)the Guangdong Provincial Key R&D Program(No.2022-GDUT-A0007)。
文摘Acetylacetone(AcAc)is a typical class ofβ-diketones with broad industrial applications due to the property of the keto-enol isomers,but its isomerization and chemical reactions at the air-droplet interface are still unclear.Hence,using combined molecular dynamics and quantum chemistry methods,the heterogeneous chemistry of AcAc at the air-droplet interface was investigated,including the attraction of AcAc isomers by the droplets,the distribution of isomers at the air-droplet interface,and the hydration reactions of isomers at the air-droplet interface.The results reveal that the preferential orientation of two AcAc isomers(keto-and enol-AcAc)to accumulate and accommodate at the acidic air-droplet interface.The isomerization of two AcAc isomers at the acidic air-droplet interface is more favorable than that at the neutral air-droplet interface because the“water bridge”structure is destroyed by H_(3)O^(+),especially for the isomerization from keto-Ac Ac to enol-AcAc.At the acidic air-droplet interface,the carbonyl or hydroxyl O-atoms of two AcAc isomers display an energetical preference to hydration.Keto-diol is the dominant products to accumulate at the air-droplet interface,and excessive keto-diol can enter the droplet interior to engage in the oligomerization.The photooxidation reaction of AcAc will increase the acidity of the air-droplet interface,which indirectly facilitate the uptake and formation of more keto-diol.Our results provide an insight into the heterogeneous chemistry ofβ-diketones and their influence on the environment.
基金the National Natural Science Foundation of China(52173163 and 22205069)the National 1000-Talents Program,the Innovation Fund of WNLO,the China Postdoctoral Science Foundation(2021TQ0115 and 2021M701302)+1 种基金Hubei province Postdoctoral Innovation Research Post FundWenzhou Science and Technology Program(ZG2022020,G20220022 and G20220026).
文摘Organic electrode materials are promising for batteries.However,the reported organic electrodes are often facing the challenges of low specific capacity,low voltage,poor rate capability and vague charge storage mechanisms,etc.Isomers are good platform to investigate the charge storage mechanisms and enhance the performance of batteries,which,however,have not been focused in batteries.Herein,two isomers are reported for batteries.As a result,the isomer tetrathiafulvalene(TTF)could store two monovalent anions reversibly,deriving an average discharge voltage of 1.05 V and a specific capacity of 220 mAh g−1 at a current density of 2 C.On the other hand,the other isomer tetrathianaphthalene could only reversibly store one monovalent anion and upon further oxidation,it would undergo an irreversible solid-state molecular rearrangement to TTF.The molecular rearrangement was confirmed by electrochemical performances,X-ray diffraction patterns,nuclear magnetic resonance spectra,and 1H detected heteronuclear multiple bond correlation spectra.These results suggested the small structural change could lead to a big difference in anion storage,and we hope this work will stimulate more attention to the structural design for boosting the performance of organic batteries.
基金the National Natural Science Foundation of China(2180212552074244)+2 种基金the Central Plains Science and Technology Innovation Leader Project(214200510006)Henan Outstanding Foreign Scientists,Workroom(GZS2018004)and the National Key R&D Program of China(2022YFC2104505)the Program of Henan Center for Oustanding Overseas Scientists(No.GZS2022007)for the financial support.
文摘Isomerization of glucose to fructose is a fundamental and key intermediate process commonly included in the production of valuable chemicals from carbohydrates in biorefinery.Enhancement of fructose yield is a challenge.In this work,Sn-doped silica nanotube(Sn-SNT)was developed as a highly efficient Lewis acid catalyst for the selective isomerization of glucose to fructose.Over Sn-SNT,69.1%fructose yield with 78.5%selectivity was obtained after reaction at 110◦C for 6 h.The sole presence of a large amount of Lewis acid sites in Sn-SNT without Brønsted acid site is one of the reasons for the high fructose yield and selectivity.Otherwise,high density of SiOH groups in Sn-SNT can ensure the presence of SiOH groups near the Sn sites,which is important for the isomerization of glucose to fructose,leading to the high fructose yield and selectivity.Furthermore,the Sn-SNT is recyclable.
基金financially supported by the National Natural Science Foundation of China(No.22101170).
文摘Azulene is a promising building block for creating innovative polycyclic aromatic hydrocarbons. This study involved the construction of three nonalternant isomers of pentacene by fusing two azulene units, named Az-PH1/2/3. Az-PH1 was initially developed through the rhodium(Ⅱ)-catalyzed cyclization of bis(N-tosylhydrazone)s. Intriguingly, Az-PH1 was also unexpectedly obtained during a nickel(0)-catalyzed one-step tandem reaction. We investigated the optical and electrochemical properties, aromaticity, and photo-oxidative stability of Az-PH1, comparing it with the well-known pentacene using density functional theory, electrochemical, and photophysical tests. Our results showed that the azulene-fusing strategy resulted in a molecule with narrow optical bandgaps(2.046 eV) and a long half-life time under ambient air conditions.
基金Financial support by Dual Initiative Project of Jiangsu Province and Changzhou University is gratefully acknowledgedSample analysis supported by Analysis and Testing Center,NERC Biomass of Changzhou University was also greatly acknowledged.
文摘The transformation of aldose to ketose or common sugars into rare saccharides,including rare ketoses and aldoses,is of great value and interest to the food industry and for saccharidic biomass utilization,medicine,and the synthesis of drugs.Nowadays,high-fructose corn syrup(HFCS)is industrially produced in more than 10 million tons annually using immobilized glucose isomerase.Some low-calorie saccharides such as tagatose and psicose,which are becoming popular sweeteners,have also been produced on a pilot scale in order to replace sucrose and HFCS.However,current catalysts and catalytic processes are still difficult to utilize in biomass conversion and also have strong substrate dependence in producing high-value,rare sugars.Considering the specific reaction properties of saccharides and catalysts,since the pioneering discovery by Fischer,various catalysts and catalytic systems have been discovered or developed in attempts to extend the reaction pathways,improve the reaction efficiency,and to potentially produce commercial products.In this review,we trace the history of sugar isomerization/epimerization reactions and summarize the important breakthroughs for each reaction as well as the difficulties that remain unresolved to date.
