To explore the potential utilization of Elaeagnus mollis,we conducted a comprehensive assessment of its phytochemical composition,antioxidant properties,cholinesterase inhibition,and anti-HepG2 cell proliferation acti...To explore the potential utilization of Elaeagnus mollis,we conducted a comprehensive assessment of its phytochemical composition,antioxidant properties,cholinesterase inhibition,and anti-HepG2 cell proliferation activity across different plant parts(branch wood,branch bark,and pericarp)using various solvents(water,methanol,ethanol,and n-hexane).Our findings revealed that water extracts displayed superior antioxidant activities in ABTS and RP assays,while methanol extracts exhibited better performance in DPPH and FRAP assays.Moreover,methanol extracts demonstrated the highest effectiveness against anti-HepG2 cell proliferation,whereas n-hexane extracts showed greater efficiency in cholinesterase inhibition.Notably,branch bark extracts exhibited the highest levels of phytochemical compounds,with both branch bark and pericarp extracts demonstrating significant effects in cholinesterase inhibition and anti-HepG2 cell proliferation.Correlation analysis indicated that phytochemical compounds were primarily responsible for the observed biological activities.Overall,extracts from the branch bark and pericarp of E.mollis showed promising potential for antioxidant and anticancer activities,suggesting their suitability for applications in the pharmaceutical industry as health-promoting products.展开更多
N-(2-Ethynylphenyl)acrylamides have emerged as key intermediates for the synthesis of complex heteropolycyclic compounds.The recent advances focus on the tandem cyclization involving these precursors,among which forma...N-(2-Ethynylphenyl)acrylamides have emerged as key intermediates for the synthesis of complex heteropolycyclic compounds.The recent advances focus on the tandem cyclization involving these precursors,among which formation of fused six/N-three,six/five(N,S,O),and six/six-membered rings are highlighted.Nitrogen,sulfur,and oxygen incorporations into five-membered rings provide efficient routes to bioactive polycyclic molecules.These cyclization reactions exhibit excellent atom economy,high efficiency,and good functional group compatibility.Furthermore,novel catalytic systems and photochemical strategies also expand the synthetic applications of these precursors.Taken together,these advancements offer versatile tools for the synthesis of intricate heterocyclic scaffolds with broad applications in organic and medicinal chemistry.展开更多
Decoupling electrical and thermal properties to enhance the figure of merit of thermoelectric materials underscores an in-depth understanding of the mechanisms that govern the transfer of charge carriers.Typically,a f...Decoupling electrical and thermal properties to enhance the figure of merit of thermoelectric materials underscores an in-depth understanding of the mechanisms that govern the transfer of charge carriers.Typically,a factor that contributes to the optimization of thermal conductivity is often found to be detrimental to the electrical transport properties.Here,we systematically investigated 26 dimeric MX_(2)-type compounds(where M represents a metal and X represents a nonmetal element)to explore the influence of the electronic configurations of metal cations on lattice thermal transport and thermoelectric performance using first-principles calculations.A principled scheme has been identified that the filled outer orbitals of the cation lead to a significantly lower lattice thermal conductivity compared to that of the partly occupied case for MX_(2),due to the much weakened bonds manifested by the shallow potential well,smaller interatomic force constants,and higher atomic displacement parameters.Based on these findings,we propose two ionic compounds,BaAs and BaSe_(2),to realize reasonable high electrical conductivities through the structural anisotropy caused by the inserted covalent X_(2) dimers while still maintaining the large lattice anharmonicity.The combined superior electrical and thermal properties of BaSe_(2) lead to a high n-type thermoelectric ZT value of 2.3 at 500 K.This work clarifies the structural origin of the heat transport properties of dimeric MX_(2)-type compounds and provides an insightful strategy for developing promising thermoelectric materials.展开更多
CO_(2) hydrogenation to methanol is a critical technology for hydrogen energy conversion and a promising approach to mitigate the energy crisis and greenhouse effect.However,developing highly selective catalysts remai...CO_(2) hydrogenation to methanol is a critical technology for hydrogen energy conversion and a promising approach to mitigate the energy crisis and greenhouse effect.However,developing highly selective catalysts remains a major challenge for its practical application.Herein,we synthesize an efficient CoCuInO-r catalyst with Cu_(11)In_(9) and Co^(0) dual sites on In_(2)O_(3) via a sol-gel method.The Cu_(11)In_(9) intermetallic compound enhances H_(2) adsorption capacity and strength,and increases oxygen vacancy concentration on the catalyst surface,thereby improving CO_(2) activation and hydrogenation efficiency.Meanwhile,Co^(0) suppresses the desorption of the*CO species,facilitating its further hydrogenation to methanol.In-situ DRIFTS experiments indicate that the CO_(2) hydrogenation to methanol over CoCuInO-r follows the formate pathway.Compared with CuInO-r(containing Cu_(11)In_(9) on In_(2)O_(3)),CoCuInO-r exhibits a~20%increase in methanol selectivity and a 2-fold higher methanol space-time yield,reaching 7.68 mmol·g^(-1)·h^(-1) at 300℃ and 4 MPa.展开更多
As an extreme physical condition,high pressure serves as a potent means to substantially modify the interatomic distances and bonding patterns within condensed matter,thereby enabling the macroscopic manipulation of m...As an extreme physical condition,high pressure serves as a potent means to substantially modify the interatomic distances and bonding patterns within condensed matter,thereby enabling the macroscopic manipulation of material properties.We employed the CALYPSO method to predict the stable structures of RbB_(2)C_(4)across the pressure range from 0 GPa to 100 GPa and investigated its physical properties through first-principles calculations.Specially,we found four novel structures,namely,P6_(3)/mcm-,Amm2-,P1-,and I4/mmm-RbB_(2)C_(4).Under pressure conditions,electronic structure calculations reveal that all of them exhibit metallic characteristics.The calculation results of formation enthalpy show that the P6_(3)/mcm structure can be synthesized within the pressure range of 0–40 GPa.Specially,the Amm2,P1,and I4/mmm structures can be synthesized above 4 GPa,6 GPa,10 GPa,respectively.Moreover,the estimated Vickers hardness value of I4/mmm-RbB_(2)C_(4)compound is 47 GPa,suggesting that it is a superhard material.Interestingly,this study uncovers the continuous transformation of the crystal structure of RbB_(2)C_(4)from a layered configuration to folded and tubular forms,ultimately attaining a stabilized cage-like structure under the pressure span of 0–100 GPa.The application of pressure offers a formidable impetus for the advancement and innovation in condensed matter physics,facilitating the exploration of novel states and functions of matter.展开更多
The rare earth(RE)-transition metal(TM)based compounds have emerged as one of the best candi-dates for the application in eco-friendly and effective cooling technology due to their outstanding cryogenic magnetocaloric...The rare earth(RE)-transition metal(TM)based compounds have emerged as one of the best candi-dates for the application in eco-friendly and effective cooling technology due to their outstanding cryogenic magnetocaloric performances.In this work,three RE-TM germanides RE_(3)Co_(2)Ge_(4)(RE=Gd,Tb and Dy)were synthesized and characterized,aiming to investigating their structural,magnetic and magnetocaloric properties.These compounds crystallize in the Tb_(3)Co_(2)Ge_(4)-type monoclinic structure(space group C2/m,Z=2).Two successive ferromagnetic transitions are observed with T_(c) of 31 and 135 K for Gd_(3)Co_(2)Ge_(4),ferromagnetic and spin reorientation transitions are observed with Tc of 24 K and T_(s) of 19 K for Dy_(3)Co_(2)Ge_(4),all of which are second ordered.In contrast,Tb_(3)Co_(2)Ge_(4)exhibits a second order antiferromagnetic transition with T_(n) of 36 K,accompanied with a spin reorientation transition with T_(s) of 17 K.Furthermore,the ferromagnetic ground state for Gd_(3)Co_(2)Ge_(4)is also confirmed by the first-principles calculations.Significant cryogenic magnetocaloric performances are observed in these compounds,.The determined maximum magnetic entropy change(-ΔS_(M)^(max))under a magnetic field change(△H)of 0-7 T are 10.7,5.3 and 11.6 J/(kg·K)for Gd_(3)Co_(2)Ge_(4),Tb_(3)Co_(2)Ge_(4)and Dy_(3)Co_(2)Ge_(4),respectively.Our results suggest that Gd_(3)Co_(2)Ge_(4)and Dy_(3)Co_(2)Ge_(4)compounds are attractive candidates for cryogenic magnetic refrigeration applications.展开更多
Carbon dioxide(CO_(2))is the main greenhouse gas(GHG)released by human activities.The substitution of fossil resources by biomass as a bio-renewable resource,has significant potential to reduce GHG emissions.The appro...Carbon dioxide(CO_(2))is the main greenhouse gas(GHG)released by human activities.The substitution of fossil resources by biomass as a bio-renewable resource,has significant potential to reduce GHG emissions.The approach to biomass,as the only true full-scale alternative to fossil resources,is progressing rapidly.Converting biomass into furanic compounds,as versatile platform chemicals for synthesizing a wide range of bio-based products is the cornerstone of sustainable technologies.The extensive body of this review combines the biomass valorization to furanic compounds by CO_(2)utilization and furanic compounds conversion by CO_(2)fixation.These processes can be strategically applied through both‘thermochemical’and‘electrochemical’pathways,by utilizing CO_(2)from the atmosphere or industrial emission point and returning it to the natural carbon cycle.In the thermochemical pathway CO_(2)acts as a carbon source(carboxylation and polymerization)or active reaction assistant in the biomass conversion(CO_(2)-assisted conversion),without altering its oxidation state,facilitating the synthesis of valuable products and polymers.Conversely,in the electrochemical pathway,CO_(2)can be used as a carbon source(electrocarboxylation)to give the corresponding carboxylic acid,or it can undergo reduction,yielding methanol,carbon monoxide(CO),formic acid,and analogous compounds,while on the other side,furanic compounds undergo oxidation yielding high-value-added chemicals.Finally,potential future research directions are suggested to promote CO_(2)utilization and fixation in the valorization of biomass-derived furanic compounds,and challenges facing further research are highlighted.展开更多
NASICON-type Na_(3)V_(2)(PO_(4))_(3)(NVP)materials are seen as highly promising cathode materials in the field of sodium-ion batteries due to their low cost,a solid three-dimensional skeleton and good theoretical capa...NASICON-type Na_(3)V_(2)(PO_(4))_(3)(NVP)materials are seen as highly promising cathode materials in the field of sodium-ion batteries due to their low cost,a solid three-dimensional skeleton and good theoretical capacity,as well as high ionic conductivity.Nevertheless,the problem of low intrinsic electronic conductivity and energy density has limited the practical application of the materials.To address this issue,the relevant research team has successfully achieved remarkable research results through unremitting exploration and practical innovation.In this work,the crystal structure,ion migration mechanism and sodium storage mechanism of NVP cathode materials are systematically reviewed,with a focus on summarizing the latest progress of V-site doping modification research,classifying and exploring V-site doping from the perspectives of electronic structure,lattice strain and entropy,and briefly describing the optimization mechanism of V-site doping on electrochemical performance.In addition,the challenges and prospects for the future development of NVP cathode materials are presented,which are believed to provide new thinking for the design and development of high-performance NVP cathode materials and contribute to the large-scale application of sodium-ion batteries.展开更多
The H2Ge=Ge：, as well as and its derivatives （X2Ge=Ge：, X=H, Me, F, C1, Br, Ph, At, ...） is a kind of new species. Its cycloaddition reactions is a new area for the study of germylene chemistry. The mechanism of t...The H2Ge=Ge：, as well as and its derivatives （X2Ge=Ge：, X=H, Me, F, C1, Br, Ph, At, ...） is a kind of new species. Its cycloaddition reactions is a new area for the study of germylene chemistry. The mechanism of the cycloaddition reaction between singlet Me2Ge=Ge： and acetaldehyde was investigated with the B3LYP/6-31G＊ method in this work. From the potential energy profile, it could be predicted that the reaction has one dominant reaction pathway. The reaction rule is that the two reactants firstly form a four-membered Ge-heterocyclic ring germylene through the [2＋2] cycloaddition reaction. Because of the 4p unoccupied orbital of Ge： atom in the four-membered Ge-heterocyclic ring germylene and the ~ orbital of acetaldehyde forming a r^--~p donor-acceptor bond, the four-membered Ge-heterocyclic ring germylene further combines with acetaldehyde to form an intermedi- ate. Because the Ge atom in intermediate happens sp3 hybridization after transition state, then, intermediate isomerizes to a spiro-Ge-heterocyclic ring compound via a transition state. The research result indicates the laws of cycloaddition reaction between Me2Ge=Ge： and ac- etaldehyde, and lays the theory foundation of the cycloaddition reaction between H2Ge=Ge： and its derivatives （X2Ge=Ge：, X=H, Me, F, C1, Br, Ph, At, ...） and asymmetric ^-bonded compounds, which are significant for the synthesis of small-ring and spiro-Ge-heterocyclic ring compounds.展开更多
H2Ge=Si： and its derivatives （X2Ge=Si：, X=H, Me, F, C1, Br, Ph, Ar, ...） are new species. Its cycloaddition reactions are new area for the study of silylene chemistry. The cycloaddition reaction mechanism of singl...H2Ge=Si： and its derivatives （X2Ge=Si：, X=H, Me, F, C1, Br, Ph, Ar, ...） are new species. Its cycloaddition reactions are new area for the study of silylene chemistry. The cycloaddition reaction mechanism of singlet H2Ge=Si： and formaldehyde has been investigated with the MP2/aug-cc-pVDZ method. From the potential energy profile, it could be predicted that the reaction has one dominant reaction pathway. The reaction rule is that two reactants firstly form a four-membered Ge-heterocyclic ring silylene through the [2＋2] cycloaddition reaction. Because of the 3p unoccupied orbital of Si： atom in the four-membered Ge-heterocyclic ring silylene and the π orbital of formaldehyde forming a π--p donor-acceptor bond, the four-membered Ge-heterocyclic ring silylene further combines with formaldehyde to form an intermediate. Because the Si： atom in the intermediate undergoes sp3 hybridization after transition state, then the intermediate isomerizes to a spiro-Si-heterocyclic ring compound involving Ge via a transition state. The result indicates the laws of cycloaddition reaction between H2Ge=Si： or its derivatives （X2Ge=Si：, X=H, Me, F, Cl, Br, Ph, Ar, ...） and asymmetric π-bonded compounds are significant for the synthesis of small-ring involving Si and Ge and spiro-Si-heterocyclic ring compounds involving Ge.展开更多
A new supramolecular compound, { [2-（2-pyridyl）benzimidazoleH2]2＋.[SBC15]2-}2, was synthesized by the hydrothermal reaction of o-diaminobenzene, 2-pyridinecarboxylie acid and SbCl3 in 1：1 HC1 solution, and charact...A new supramolecular compound, { [2-（2-pyridyl）benzimidazoleH2]2＋.[SBC15]2-}2, was synthesized by the hydrothermal reaction of o-diaminobenzene, 2-pyridinecarboxylie acid and SbCl3 in 1：1 HC1 solution, and characterized by chemical analysis, elemental analysis, IR spectra, thermogravimetfic analysis and fluorescence spectra. The crystal structure was deter- mined by X-ray single-crystal diffraction. The crystal belongs to the monoclinic system, space group P211c, with a = 16.0397（13）, b = 14.3189（12）, c = 15.6370（13） A, β = 105.8980（10）°, V = 3454.0（5） A3, Z = 4, C24H22Cl10N6Sb2, Mr = 992.48, Dc = 1.909 g/cm3,/z = 2.366 mm-1, S = 1.010, F（000） = 1920, R = 0.0254 and wR = 0.0555. The coordination anion, [SbCl5]2- which is a distorted tetragonal pyramid, is composed by coordinating action with Sb3＋ ion and five adjacent chloride ions. Every four coordination anions of [SbCl5]2- form a biquaternion ring structure through the secondary bonding of Sb...Cl. Moreover, the compound adopts a three-dimensional network supramolecular structure because of the hydrogen bonds and π-π stacking between the rings and the 2-（2-pyridyl）benzimidazole divalent cations. The title compound also shows good fluorescent behaviors.展开更多
基金National Natural Science Foundation of China(Grant No.31600549).
文摘To explore the potential utilization of Elaeagnus mollis,we conducted a comprehensive assessment of its phytochemical composition,antioxidant properties,cholinesterase inhibition,and anti-HepG2 cell proliferation activity across different plant parts(branch wood,branch bark,and pericarp)using various solvents(water,methanol,ethanol,and n-hexane).Our findings revealed that water extracts displayed superior antioxidant activities in ABTS and RP assays,while methanol extracts exhibited better performance in DPPH and FRAP assays.Moreover,methanol extracts demonstrated the highest effectiveness against anti-HepG2 cell proliferation,whereas n-hexane extracts showed greater efficiency in cholinesterase inhibition.Notably,branch bark extracts exhibited the highest levels of phytochemical compounds,with both branch bark and pericarp extracts demonstrating significant effects in cholinesterase inhibition and anti-HepG2 cell proliferation.Correlation analysis indicated that phytochemical compounds were primarily responsible for the observed biological activities.Overall,extracts from the branch bark and pericarp of E.mollis showed promising potential for antioxidant and anticancer activities,suggesting their suitability for applications in the pharmaceutical industry as health-promoting products.
基金Project supported by the Special Fund Project for Scientific Research Openness of the Key Laboratory of Medical Conditioning Functional Food Processing Technology in Weihai City(No.WHYY20240006)the Mid-Young Teachers Visiting Program of Qingdao Agricultural University(No.2024)+1 种基金the General Education Reform and Research Project of Qingdao Agricultural University(No.XJY2024063)the Research Results of the Ideological and Political Education Research Project of Qingdao Agricultural University(No:QNSZ2025023)。
文摘N-(2-Ethynylphenyl)acrylamides have emerged as key intermediates for the synthesis of complex heteropolycyclic compounds.The recent advances focus on the tandem cyclization involving these precursors,among which formation of fused six/N-three,six/five(N,S,O),and six/six-membered rings are highlighted.Nitrogen,sulfur,and oxygen incorporations into five-membered rings provide efficient routes to bioactive polycyclic molecules.These cyclization reactions exhibit excellent atom economy,high efficiency,and good functional group compatibility.Furthermore,novel catalytic systems and photochemical strategies also expand the synthetic applications of these precursors.Taken together,these advancements offer versatile tools for the synthesis of intricate heterocyclic scaffolds with broad applications in organic and medicinal chemistry.
基金financial support from the Natural Science Foundation of China(No.11904089,12174092,11674087)the Overseas Expertise Introduction Center for Discipline Innovation(D18025)+1 种基金the Program for Key Research and Development of Science and Technology in Hubei Province(grant No.2023BEB002)supported by the Young Science Foundation of Hubei University(Grant No.430/184303000047).
文摘Decoupling electrical and thermal properties to enhance the figure of merit of thermoelectric materials underscores an in-depth understanding of the mechanisms that govern the transfer of charge carriers.Typically,a factor that contributes to the optimization of thermal conductivity is often found to be detrimental to the electrical transport properties.Here,we systematically investigated 26 dimeric MX_(2)-type compounds(where M represents a metal and X represents a nonmetal element)to explore the influence of the electronic configurations of metal cations on lattice thermal transport and thermoelectric performance using first-principles calculations.A principled scheme has been identified that the filled outer orbitals of the cation lead to a significantly lower lattice thermal conductivity compared to that of the partly occupied case for MX_(2),due to the much weakened bonds manifested by the shallow potential well,smaller interatomic force constants,and higher atomic displacement parameters.Based on these findings,we propose two ionic compounds,BaAs and BaSe_(2),to realize reasonable high electrical conductivities through the structural anisotropy caused by the inserted covalent X_(2) dimers while still maintaining the large lattice anharmonicity.The combined superior electrical and thermal properties of BaSe_(2) lead to a high n-type thermoelectric ZT value of 2.3 at 500 K.This work clarifies the structural origin of the heat transport properties of dimeric MX_(2)-type compounds and provides an insightful strategy for developing promising thermoelectric materials.
基金financial support from the National Key Research and Development Program of China(2022YFB4101800)National Natural Science Foundation of China(22278298)the Key Research&Development Program of Shandong Province,China(2024CXGC010410).
文摘CO_(2) hydrogenation to methanol is a critical technology for hydrogen energy conversion and a promising approach to mitigate the energy crisis and greenhouse effect.However,developing highly selective catalysts remains a major challenge for its practical application.Herein,we synthesize an efficient CoCuInO-r catalyst with Cu_(11)In_(9) and Co^(0) dual sites on In_(2)O_(3) via a sol-gel method.The Cu_(11)In_(9) intermetallic compound enhances H_(2) adsorption capacity and strength,and increases oxygen vacancy concentration on the catalyst surface,thereby improving CO_(2) activation and hydrogenation efficiency.Meanwhile,Co^(0) suppresses the desorption of the*CO species,facilitating its further hydrogenation to methanol.In-situ DRIFTS experiments indicate that the CO_(2) hydrogenation to methanol over CoCuInO-r follows the formate pathway.Compared with CuInO-r(containing Cu_(11)In_(9) on In_(2)O_(3)),CoCuInO-r exhibits a~20%increase in methanol selectivity and a 2-fold higher methanol space-time yield,reaching 7.68 mmol·g^(-1)·h^(-1) at 300℃ and 4 MPa.
基金Project supported by the Jilin Provincial Science and Technology Development Joint Fund Project(Grant No.YDZJ202201ZYTS581)supported by the Scientific and Technological Research Project of Jilin Provincial Education Department(Grant No.JJKH20240077KJ).
文摘As an extreme physical condition,high pressure serves as a potent means to substantially modify the interatomic distances and bonding patterns within condensed matter,thereby enabling the macroscopic manipulation of material properties.We employed the CALYPSO method to predict the stable structures of RbB_(2)C_(4)across the pressure range from 0 GPa to 100 GPa and investigated its physical properties through first-principles calculations.Specially,we found four novel structures,namely,P6_(3)/mcm-,Amm2-,P1-,and I4/mmm-RbB_(2)C_(4).Under pressure conditions,electronic structure calculations reveal that all of them exhibit metallic characteristics.The calculation results of formation enthalpy show that the P6_(3)/mcm structure can be synthesized within the pressure range of 0–40 GPa.Specially,the Amm2,P1,and I4/mmm structures can be synthesized above 4 GPa,6 GPa,10 GPa,respectively.Moreover,the estimated Vickers hardness value of I4/mmm-RbB_(2)C_(4)compound is 47 GPa,suggesting that it is a superhard material.Interestingly,this study uncovers the continuous transformation of the crystal structure of RbB_(2)C_(4)from a layered configuration to folded and tubular forms,ultimately attaining a stabilized cage-like structure under the pressure span of 0–100 GPa.The application of pressure offers a formidable impetus for the advancement and innovation in condensed matter physics,facilitating the exploration of novel states and functions of matter.
基金the Science and Technology Development Fund,Macao SAR,China(006/2022/ALC).
文摘The rare earth(RE)-transition metal(TM)based compounds have emerged as one of the best candi-dates for the application in eco-friendly and effective cooling technology due to their outstanding cryogenic magnetocaloric performances.In this work,three RE-TM germanides RE_(3)Co_(2)Ge_(4)(RE=Gd,Tb and Dy)were synthesized and characterized,aiming to investigating their structural,magnetic and magnetocaloric properties.These compounds crystallize in the Tb_(3)Co_(2)Ge_(4)-type monoclinic structure(space group C2/m,Z=2).Two successive ferromagnetic transitions are observed with T_(c) of 31 and 135 K for Gd_(3)Co_(2)Ge_(4),ferromagnetic and spin reorientation transitions are observed with Tc of 24 K and T_(s) of 19 K for Dy_(3)Co_(2)Ge_(4),all of which are second ordered.In contrast,Tb_(3)Co_(2)Ge_(4)exhibits a second order antiferromagnetic transition with T_(n) of 36 K,accompanied with a spin reorientation transition with T_(s) of 17 K.Furthermore,the ferromagnetic ground state for Gd_(3)Co_(2)Ge_(4)is also confirmed by the first-principles calculations.Significant cryogenic magnetocaloric performances are observed in these compounds,.The determined maximum magnetic entropy change(-ΔS_(M)^(max))under a magnetic field change(△H)of 0-7 T are 10.7,5.3 and 11.6 J/(kg·K)for Gd_(3)Co_(2)Ge_(4),Tb_(3)Co_(2)Ge_(4)and Dy_(3)Co_(2)Ge_(4),respectively.Our results suggest that Gd_(3)Co_(2)Ge_(4)and Dy_(3)Co_(2)Ge_(4)compounds are attractive candidates for cryogenic magnetic refrigeration applications.
基金the National Key R&D Program of China(No.2021YFC2101604)National Natural Science Foundation of China(Nos.U23A20123,22278339)+1 种基金Fujian Provincial Key Science and Technology Program of China(No.2022YZ037013)Xiamen University for the financial support.
文摘Carbon dioxide(CO_(2))is the main greenhouse gas(GHG)released by human activities.The substitution of fossil resources by biomass as a bio-renewable resource,has significant potential to reduce GHG emissions.The approach to biomass,as the only true full-scale alternative to fossil resources,is progressing rapidly.Converting biomass into furanic compounds,as versatile platform chemicals for synthesizing a wide range of bio-based products is the cornerstone of sustainable technologies.The extensive body of this review combines the biomass valorization to furanic compounds by CO_(2)utilization and furanic compounds conversion by CO_(2)fixation.These processes can be strategically applied through both‘thermochemical’and‘electrochemical’pathways,by utilizing CO_(2)from the atmosphere or industrial emission point and returning it to the natural carbon cycle.In the thermochemical pathway CO_(2)acts as a carbon source(carboxylation and polymerization)or active reaction assistant in the biomass conversion(CO_(2)-assisted conversion),without altering its oxidation state,facilitating the synthesis of valuable products and polymers.Conversely,in the electrochemical pathway,CO_(2)can be used as a carbon source(electrocarboxylation)to give the corresponding carboxylic acid,or it can undergo reduction,yielding methanol,carbon monoxide(CO),formic acid,and analogous compounds,while on the other side,furanic compounds undergo oxidation yielding high-value-added chemicals.Finally,potential future research directions are suggested to promote CO_(2)utilization and fixation in the valorization of biomass-derived furanic compounds,and challenges facing further research are highlighted.
基金supported by the National Natural Science Foundation of China(no.52574348)the Natural Science Foundation of Hebei Province(no.B2024501004)+2 种基金the Fundamental Research Funds for the Central Universities(no.N2423013)the Shijiazhuang Basic Research Project(no.241790667A)the Performance Subsidy Fund for Key Laboratory of Dielectric and Electrolyte Functional Material Hebei Province(no.22567627H).
文摘NASICON-type Na_(3)V_(2)(PO_(4))_(3)(NVP)materials are seen as highly promising cathode materials in the field of sodium-ion batteries due to their low cost,a solid three-dimensional skeleton and good theoretical capacity,as well as high ionic conductivity.Nevertheless,the problem of low intrinsic electronic conductivity and energy density has limited the practical application of the materials.To address this issue,the relevant research team has successfully achieved remarkable research results through unremitting exploration and practical innovation.In this work,the crystal structure,ion migration mechanism and sodium storage mechanism of NVP cathode materials are systematically reviewed,with a focus on summarizing the latest progress of V-site doping modification research,classifying and exploring V-site doping from the perspectives of electronic structure,lattice strain and entropy,and briefly describing the optimization mechanism of V-site doping on electrochemical performance.In addition,the challenges and prospects for the future development of NVP cathode materials are presented,which are believed to provide new thinking for the design and development of high-performance NVP cathode materials and contribute to the large-scale application of sodium-ion batteries.
文摘The H2Ge=Ge：, as well as and its derivatives （X2Ge=Ge：, X=H, Me, F, C1, Br, Ph, At, ...） is a kind of new species. Its cycloaddition reactions is a new area for the study of germylene chemistry. The mechanism of the cycloaddition reaction between singlet Me2Ge=Ge： and acetaldehyde was investigated with the B3LYP/6-31G＊ method in this work. From the potential energy profile, it could be predicted that the reaction has one dominant reaction pathway. The reaction rule is that the two reactants firstly form a four-membered Ge-heterocyclic ring germylene through the [2＋2] cycloaddition reaction. Because of the 4p unoccupied orbital of Ge： atom in the four-membered Ge-heterocyclic ring germylene and the ~ orbital of acetaldehyde forming a r^--~p donor-acceptor bond, the four-membered Ge-heterocyclic ring germylene further combines with acetaldehyde to form an intermedi- ate. Because the Ge atom in intermediate happens sp3 hybridization after transition state, then, intermediate isomerizes to a spiro-Ge-heterocyclic ring compound via a transition state. The research result indicates the laws of cycloaddition reaction between Me2Ge=Ge： and ac- etaldehyde, and lays the theory foundation of the cycloaddition reaction between H2Ge=Ge： and its derivatives （X2Ge=Ge：, X=H, Me, F, C1, Br, Ph, At, ...） and asymmetric ^-bonded compounds, which are significant for the synthesis of small-ring and spiro-Ge-heterocyclic ring compounds.
文摘H2Ge=Si： and its derivatives （X2Ge=Si：, X=H, Me, F, C1, Br, Ph, Ar, ...） are new species. Its cycloaddition reactions are new area for the study of silylene chemistry. The cycloaddition reaction mechanism of singlet H2Ge=Si： and formaldehyde has been investigated with the MP2/aug-cc-pVDZ method. From the potential energy profile, it could be predicted that the reaction has one dominant reaction pathway. The reaction rule is that two reactants firstly form a four-membered Ge-heterocyclic ring silylene through the [2＋2] cycloaddition reaction. Because of the 3p unoccupied orbital of Si： atom in the four-membered Ge-heterocyclic ring silylene and the π orbital of formaldehyde forming a π--p donor-acceptor bond, the four-membered Ge-heterocyclic ring silylene further combines with formaldehyde to form an intermediate. Because the Si： atom in the intermediate undergoes sp3 hybridization after transition state, then the intermediate isomerizes to a spiro-Si-heterocyclic ring compound involving Ge via a transition state. The result indicates the laws of cycloaddition reaction between H2Ge=Si： or its derivatives （X2Ge=Si：, X=H, Me, F, Cl, Br, Ph, Ar, ...） and asymmetric π-bonded compounds are significant for the synthesis of small-ring involving Si and Ge and spiro-Si-heterocyclic ring compounds involving Ge.
基金Supported by the Natural Science Foundation of Henan Province (No. 0611023700)Natural Science Foundation of Education Department of Henan Province (No. 2006150019)
文摘A new supramolecular compound, { [2-（2-pyridyl）benzimidazoleH2]2＋.[SBC15]2-}2, was synthesized by the hydrothermal reaction of o-diaminobenzene, 2-pyridinecarboxylie acid and SbCl3 in 1：1 HC1 solution, and characterized by chemical analysis, elemental analysis, IR spectra, thermogravimetfic analysis and fluorescence spectra. The crystal structure was deter- mined by X-ray single-crystal diffraction. The crystal belongs to the monoclinic system, space group P211c, with a = 16.0397（13）, b = 14.3189（12）, c = 15.6370（13） A, β = 105.8980（10）°, V = 3454.0（5） A3, Z = 4, C24H22Cl10N6Sb2, Mr = 992.48, Dc = 1.909 g/cm3,/z = 2.366 mm-1, S = 1.010, F（000） = 1920, R = 0.0254 and wR = 0.0555. The coordination anion, [SbCl5]2- which is a distorted tetragonal pyramid, is composed by coordinating action with Sb3＋ ion and five adjacent chloride ions. Every four coordination anions of [SbCl5]2- form a biquaternion ring structure through the secondary bonding of Sb...Cl. Moreover, the compound adopts a three-dimensional network supramolecular structure because of the hydrogen bonds and π-π stacking between the rings and the 2-（2-pyridyl）benzimidazole divalent cations. The title compound also shows good fluorescent behaviors.
