Iron-nitrogen-carbon(Fe-N-C)materials with Fe-N_(4)structures have been considered as the most promising alternatives of scarce and precious platinum(Pt)for oxygen reduction reaction.Particularly,the hightemperature p...Iron-nitrogen-carbon(Fe-N-C)materials with Fe-N_(4)structures have been considered as the most promising alternatives of scarce and precious platinum(Pt)for oxygen reduction reaction.Particularly,the hightemperature pyrolysis of a precursor mixture of N-containing amine polymers,Fe salts,and carbon supports,has become a popular method for the synthesis of high-performance Fe-N-C catalysts.The oxidative polymerization of amine monomers can usually proceed under acidic conditions,however,the acidcaused protonation of N-groups is not conducive to their coordination with Fe ions for the formation of high-density Fe-N_(4)sites.Here,we propose a protonation elimination strategy of soaking the polymerization products in alkaline solutions to increase Fe-N_(4)active sites.Theoretical calculations display that the Gibbs free energy change values of binding reactions between Fe ions and N-groups are-3.70 and-26.99 kcal/mol at p H 0 and 7,respectively,suggesting that the deprotonation can facilitate the Fe-N coordination.There is a two-fold increase in the number of Fe-N_(4)active sites for final Fe-N-C catalyst which exhibits significantly enhanced ORR activity and excellent Zn-air battery performance.This deprotonation effect can be applied to different amine compounds and transition-metal ions as a universal strategy for the development of preeminent non-precious metal carbon catalysts.展开更多
Among all the DNA components, extremely redox-active guanine （G） and adenine （A） bases are subject to facile loss of an electron and form cation radicals （G＋＂ and A＋＇） when exposed to irradiation or radical ...Among all the DNA components, extremely redox-active guanine （G） and adenine （A） bases are subject to facile loss of an electron and form cation radicals （G＋＂ and A＋＇） when exposed to irradiation or radical oxidants. The subsequent deprotonation of G＋＇ and A＋＇ can invoke DNA damage or interrupt hole transfer in DNA. However, compared with intensive reports for G＋, studies on the deprotonation of A＋ are still limited at present. Herein, we investigate the deprotonation behavior of A＋. by time-resolved laser flash photolysis. The deprotonation product of A（N6-H）＇ is observed and the deprotonation rate constant, （2.0±0.1）×10 7 s-1, is obtained at room temperature. Further, the deprotonation rate con- stants of A＋. are measured at temperatures varying from 280 K to 300 K, from which the activation energy for the N6-H deprotonation is determined to be （17.1±1.0） kJ/mol by Arrhenius equation. In addition, by incorporating the aqueous solvent effect, we perform density functional theory calculations for A＋ deprotonation in free base and in duplex DNA. Together with experimental results, the deprotonation mechanisms of A＋ in free base and in duplex DNA are revealed, which are of fundamental importance for understanding the oxidative DNA damage and designing DNA-based electrochemical devices.展开更多
Nucleophile oxidation reaction(NOR),represented by ethanol oxidation reaction(EOR),is a promising pathway to replace oxygen evolution reaction(OER).EOR can effectively reduce the driving voltage of hydrogen production...Nucleophile oxidation reaction(NOR),represented by ethanol oxidation reaction(EOR),is a promising pathway to replace oxygen evolution reaction(OER).EOR can effectively reduce the driving voltage of hydrogen production in direct water splitting.In this work,large current and high efficiency of EOR on a Ni,Fe layered double hydroxide(NiFe-LDH)catalyst were simultaneously achieved by a facile fluorination strategy.F in NiFe-LDH can reduce the activation energy of the dehydrogenation reaction,thus promoting the deprotonation process of NiFe-LDH to achieve a lower EOR onset potential.It also weakens the absorption of OH-and nucleophile electrooxidation products on the surface of NiFe-LDH at a higher potential,achieving a high current density and EOR selectivity,according to density functional theory calculations.Based on our experiment results,the optimized fluorinated NiFe-LDH catalyst achieves a low potential of 1.386 V to deliver a 10 mA cm^(-2)EOR.Moreover,the Faraday efficiency is greater than 95%,with a current density ranging from 10 to 250 mA cm^(-2).This work provides a promising pathway for an efficient and cost-effective NOR catalyst design for economic hydrogen production.展开更多
Perovskite solar cells provide an economically viable and highly efficient pathway to harness solar energy.However,the instability of the organic component in hybrid perovskites presents a fundamental challenge that c...Perovskite solar cells provide an economically viable and highly efficient pathway to harness solar energy.However,the instability of the organic component in hybrid perovskites presents a fundamental challenge that constrains the longevity and performance of perovskite photovoltaics.In this study,we introduce a molecular deuteration strategy to stabilize FAPbI_(3)perovskite by replacing the active hydrogen in the N–H bond with its heavier isotope,deuterium.The reduced ground-state energy of the isotopic N–D bond induces a deuteration kinetic isotope effect,which significantly decreases the rate constant of the deprotonation reaction from 5.15×10^(−8)to 2.42×10^(−8)s^(−1).Solar cells fabricated using deuterated FAPbI_(3)thin films achieve a power conversion efficiency of 25.08%and exhibit a T97 lifetime of 1264 h under continuous one-sun illumination at 55℃.This approach paves the way for developing inherently stable perovskite materials and extending the operational lifespan of solar cell devices.展开更多
Aerogels with regularly porous structure and uniformly distributed conductive networks have received extensive attention in wearable electronic sensors,electromagnetic shielding,and so on.However,the poor mechanical p...Aerogels with regularly porous structure and uniformly distributed conductive networks have received extensive attention in wearable electronic sensors,electromagnetic shielding,and so on.However,the poor mechanical properties of the emerging nanofibers-based aerogels are limited in practical applications.In this work,we developed a synchronous deprotonation–protonation method in the KOH/dimethyl sulfoxide(DMSO)system at room temperature for achieving chitin cross-linked aramid nanofibers(CANFs)rather than chitin nanofibers(ChNFs)and aramid nanofibers(ANFs)separately by using chitin and aramid pulp as raw materials.After freeze-drying process,the cross-linked chitin/aramid nanofibers(CA)aerogel exhibited the synergetic properties of ChNF and ANF by the dual-nanofiber compensation strategy.The mechanical stress of CA aerogel was 170 kPa at 80%compressive strain,increased by 750%compared with pure ChNF aerogel.Similarly,the compressibility of CA aerogel was somewhat improved compared to ANF aerogel.The enhancement verified that the crosslinking reaction between ANF and ChNF during the synchronous deprotonation process was formed.Afterwards,the conductive aerogels with uniform porous structure(CA-M)were successfully obtained by vacuum impregnating CA aerogels in Ti_(3)C_(2)T_(x) MXene solution,displaying low thermal conductivity(0.01 W/(m·K)),high electromagnetic interference(EMI)shielding effectiveness(SE)(75 dB),flame retardant,and heat insulation.Meanwhile,the as-obtained CA-M aerogels were also applied as a pressure sensor with excellent compression cycle stability and superior human motion monitoring capabilities.As a result,the dual-nanofiber based conductive aerogels have great potentials in flexible/wearable electronics,EMI shielding,flame retardant,and heat insulation.展开更多
Two rosamine-based pH probes 1a and 1b with pyronine-phenol skeleton were designed and synthesized by a simple one-step reaction, pH titration experiments showed that probes 1a and 1b exhibit near OFF-ON fluorescence ...Two rosamine-based pH probes 1a and 1b with pyronine-phenol skeleton were designed and synthesized by a simple one-step reaction, pH titration experiments showed that probes 1a and 1b exhibit near OFF-ON fluorescence responses around 550--750 nm towards the hydrogen ions. The pKa of the probe 1a is 8.29, while that of the probe lb increases to 12.1 because of the hydrogen bond inside it. Selective and competitive experiments indicated that both common ions and amino acids did not interfere their emission with hydrogen ions. Moreover, confocal fluorescent imaging showed that the probe la could be served as mitochondria biomarker in HeLa and Ges-1 cells.展开更多
Ion-solvaing membranes(ISMs)have received extensive attention in recent years as a key component in electrochemical energy conversion and storage devices.This article provides an overview of structural composition,per...Ion-solvaing membranes(ISMs)have received extensive attention in recent years as a key component in electrochemical energy conversion and storage devices.This article provides an overview of structural composition,performance advan-tages,research progress,ion conduction mechanism and existing issues of ISMs,primarily classifying them according to the matrix structure.A detailed analysis of performance enhancement methods,key performance indicators of ISMs and performance influencing factors is also presented.The article contributes to further optimizing the design and application of ion-solvation membranes,providing theoretical support for the development of fields such as hydrogen production through electrolysis of water and electrochemical energy in the future.展开更多
The development of a highly efficient noniridium-based oxygen evolution reaction catalyst is the key to realizing large-scale commercial application of the proton-exchange membrane water electrolyzer.RuO_(2)is the mos...The development of a highly efficient noniridium-based oxygen evolution reaction catalyst is the key to realizing large-scale commercial application of the proton-exchange membrane water electrolyzer.RuO_(2)is the most promising alternative to IrO_(2),but if usually suffers from lattice-oxygenmediated corrosion and sluggish proton transfer kinetics under acidic media.Herein,we propose an effective strategy of embedding RuO_(2)nanoparticles into a N-doped carbon support,termed as RuO_(2)-NC,to simultaneously prevent Ru dissolution and accelerate the bridging-oxygen-assisted deprotonation process.The obtained RuO_(2)-NC electrocatalyst presents high activity with an overpotential of 159 mV to reach 10 mA cm^(−2) and remarkable stability for over 240 h.Structural investigation and theoretical calculations reveal that the electron-rich NC substrate,as an electron donor,provides a buffered charge compensation to protect RuO_(2)from excessive oxidation and lattice oxygen loss by switching into a conventional adsorbate evolution mechanism(AEM).More importantly,the activated bridging oxygen(Obri)sites can facilitate the deprotonation of*OOH intermediates,leading to an optimized bridging-oxygen-assisted deprotonation AEM pathway.展开更多
Phosphonium or arsonium salt with primary alcohol can undergo the tandem reaction of deprotonation-oxidation-Wittig reaction in the presence of sodium hydroxide and manganese dioxide, providing a general and efficient...Phosphonium or arsonium salt with primary alcohol can undergo the tandem reaction of deprotonation-oxidation-Wittig reaction in the presence of sodium hydroxide and manganese dioxide, providing a general and efficient method for the stereoselective synthesis of (E) -α, β-unsaturated enoates.展开更多
Efficient and stable electrocatalyst for oxygen evolution reaction(OER)in acidic environment is vital for polymer electrolyte membrane water electrolysis(PEMWE).In this work,we have devised the formation of heterostru...Efficient and stable electrocatalyst for oxygen evolution reaction(OER)in acidic environment is vital for polymer electrolyte membrane water electrolysis(PEMWE).In this work,we have devised the formation of heterostructured RuO_(2)/MnO_(2)with nanoflower structure for acidic OER catalysis.Compared to commercial RuO_(2),the overpotential at 50mA/cm^(2)is decreased by 36 mV,corresponding to a 3.7-fold better mass activity.The boosted acidic OER performance is attributed to the heterostructure inducing more electrons are filled in e_(g)orbital of Ru atom triggering a better deprotonation of bridge oxygen atom in Ru-O_(bri)-Mn structure evidenced by pH-independent cyclic voltammetry test.Moreover,RuO_(2)/MnO_(2)sustains its acidic OER activity within 20 h,longer than commercial RuO_(2).The membrane electrode assembly(MEA)test suggests than only 2.18 V is required to achieve a current density of 5 A/cm^(2).The theoretical calculation reveals that the e_(g)filling of Ru atom is increased from 2.18 to 2.39 after MnO_(2)incorporation,reducing the energy for the formation of ∗OOH moiety.展开更多
Proton exchange membrane water electrolysis(PEMWE)technology is widely recognized as a cornerstone for green hydrogen production,offering high operational current densities exceeding 1.0 A cm^(-2),rapid dynamic respon...Proton exchange membrane water electrolysis(PEMWE)technology is widely recognized as a cornerstone for green hydrogen production,offering high operational current densities exceeding 1.0 A cm^(-2),rapid dynamic response capabilities,and zero-carbon emission characteristics[1].However,the sluggish kinetics of oxygen evolution reaction(OER)at the anode presents a critical bottleneck for large-scale commercial deployment(Fig.1(a)).Despite significant advancements through electronic structure modulation[2]and coordination environment optimization[3],the deprotonation energy barrier of oxygen-containing intermediates and the stability of active sites under acidic conditions remain unresolved challenges.展开更多
Tetracycline hydrochloride(TCH)exists in various forms in aqueous solution due to pH changes,which not only alters the reactivity of TCH,but also affects the process of reactive oxygen species(ROS)attacking the molecu...Tetracycline hydrochloride(TCH)exists in various forms in aqueous solution due to pH changes,which not only alters the reactivity of TCH,but also affects the process of reactive oxygen species(ROS)attacking the molecule.Therefore,the rational design of piezo-photocatalytic materials coupled with a comprehensive understanding of the degradation mechanisms of various TCH species constitutes a critical approach to addressing tetracycline antibiotic contamination.In the design and preparation of piezo-photocatalysts,controlling the oxygen vacancy concentration is crucial as it governs the coupling efficiency between piezoelectric response and photocatalytic activity,as well as the strength of spontaneous polarization.Meanwhile,the morphology of the material is a key factor influencing the migration pathways of charge carriers.In this work,hollow spherical Bi_(4)Ti_(3)O_(12) was synthesized using an inorganic titanium source,demonstrating exceptional piezo-photocatalytic activity.The degradation rate was 1.57 and 5.29 times higher than that of traditional spherical and plate-like morphologies,with a rate constant of k=0.127.In an innovative approach,density functional theory calculations of local softness and hyper-softness were employed to analyze the reactivity changes of TCH in its different deprotonated states toward reactive oxygen species.Combined with molecular electronegativity analysis,the factors influencing the degradation efficiency were identified.This study provides a solid foundation for developing efficient and environmentally friendly piezo-photocatalysts and offers new insights into the degradation mechanism of TCH.展开更多
The title compound, 1,2-bis-（p-nitro-phenylsulfonamido）-4,5-dinitrobenzene, was synthesized and characterized by elemental analysis, IR and 1H NMR. A pale yellow prism crystal of C23H26N8O13S2 （Mr = 686.64） was ob...The title compound, 1,2-bis-（p-nitro-phenylsulfonamido）-4,5-dinitrobenzene, was synthesized and characterized by elemental analysis, IR and 1H NMR. A pale yellow prism crystal of C23H26N8O13S2 （Mr = 686.64） was obtained in DMF solution and determined by single-crystal X-ray diffraction method. It crystallizes in triclinic system, space group P1 with a = 10.346（4）, b = 12.210（5）, c = 12.976（5）A , α = 108.220（8）, β = 99.482（4）, γ = 95.490（4）°, V = 1516.7（10） A^3, Z = 2, Dc = 1.504 g/cm^3, F（000） = 712, μ = 0.254, Mr = 686.64, the final R = 0.0561 and wR = 0.1487. One sulfonamido group of the title compound is deprotoned and forms N（3）=C（13）. The crystal involves N,N-dimethylamine from the decomposition of DMF and the proton is transferred to N,N- dimethylamine. It is a strong proof for the characterization of deprotoned recognition compound by X-ray single-crystal structure.展开更多
The isomerization of hydrofluorocyclopentenes promoted by fluoride anion was investigated. It was found that two processes were responsible for interconversion of the isomers: an allylic syn-addition/elimination of fl...The isomerization of hydrofluorocyclopentenes promoted by fluoride anion was investigated. It was found that two processes were responsible for interconversion of the isomers: an allylic syn-addition/elimination of fluoride anion that does not change the mutual positions of hydrogen atoms but is responsible for transfers of fluorine atoms, and a fluoride anion-assisted deprotonation/protonation which does not change the mutual positions of fluorine atoms but is responsible for transfers of hydrogen atoms. In the deprotonation, HF can easily capture excess fluoride anion to form HF2- anion which can probably inhibit the protonation.展开更多
Aqueous rechargeable batteries using abundant multi-ion cations have receivedincreasing attention in the energy storage field for their high safety and low cost.Layered double hydroxides(LDHs)possess a two-dimensional...Aqueous rechargeable batteries using abundant multi-ion cations have receivedincreasing attention in the energy storage field for their high safety and low cost.Layered double hydroxides(LDHs)possess a two-dimensional structure andexhibit great potential as cathodes for multi-ion intercalation.However,theinsufficient active sites of LDHs result in low capacities in the discharging process.Interestingly,the LDHs after the deprotonation process exhibit favorable electrochemicalperformance of multi-cation intercalation.The deprotonation process ofLDHs has been widely found in the oxygen evolution reaction and energy storagefield,where LDHs lose H in laminates and converts to deprotonatedγ-phaseMOOHs(MOOs).Herein,we take a comprehensive overview of the dynamicsstructure transformation of the deprotonation process of LDHs.Furthermore,thedevelopment of advanced aqueous battery cathode and metal battery anode basedon deprotonated LDHs for energy storage is explored and summarized.Finally,theperspective of deprotonated LDHs in the energy storage field is discussed.展开更多
Raman spectra of 1,2,4-triazole-3-carboxylate (TC- anion) and its ring-deprotonated deriva- tive (dpTC2- dianion) in aqueous solutions were measured respectively. The density func- tional theory calculations were perf...Raman spectra of 1,2,4-triazole-3-carboxylate (TC- anion) and its ring-deprotonated deriva- tive (dpTC2- dianion) in aqueous solutions were measured respectively. The density func- tional theory calculations were performed using MN15 functional and PCM solvent model to investigate their structures, as well as the vibrational frequencies and Raman intensi- ties. With the aid of the calculated spectra, all the observed Raman bands of dpTC2- were clearly assigned, with taking into account the deuteration shifts. Moreover, various protonic tautomers of TC- anion were compared in the present theoretical calculations, and 2H- tautomer was found more stable. The experimental Raman spectrum of TC- solution was roughly consistent with the calculated spectrum of the monomeric 2H-tautomer of TC-, but some splits existed for a few bands when compared to the calculated spectra, which might be contributed by the hydrogen-bonding dimers of TC-.展开更多
Nanopore detection is a hot issue in current research.One of the challenges is how to slow down the transport velocity of nanoparticles in nanopores.In this paper,we propose a functional group modified nanopore.That m...Nanopore detection is a hot issue in current research.One of the challenges is how to slow down the transport velocity of nanoparticles in nanopores.In this paper,we propose a functional group modified nanopore.That means a polyelectrolyte brush layer is grafted on the surface of the nanopore to change the surface charge properties.The existing studies generally set the charge density of the brush layer to a fixed value.On the contrary,in this paper,we consider an essential property of the brush layer:the volume charge density is adjustable with pH.Thus,the charge property of the brush layer will change with the local H+concentration.Based on this,we established a mathematical model to study the transport of nanoparticles in polyelectrolyte brush layer modified nanopores.We found that pH can effectively adjust the charge density and even the polarity of the brush layer.A larger pH can reduce the transport velocity of nanoparticles and improve the blockade degree of ion current.The grafting density does not change the polarity of the brush charge.The larger the grafting density,the greater the charge density of the brush layer,and the blockade degree of ion current is also more obvious.The polyelectrolyte brush layer modified nanopores in this paper can effectively reduce the nanoparticle transport velocity and retain the essential ion current characteristics,such as ion current blockade and enhancement.展开更多
Mannich-type reactions are a widely used method for the synthesis of amines due to the readily availability of nucleophiles and electrophiles.However,the inclusion of alkylarenes instead of active carbon pronucleophil...Mannich-type reactions are a widely used method for the synthesis of amines due to the readily availability of nucleophiles and electrophiles.However,the inclusion of alkylarenes instead of active carbon pronucleophiles such as aldehydes and ketones in these addition reactions has been a challenge due to the inherent difficulty of benzylic deprotonation.In this study,we present a novel approach for the construction of N-sulfonyl amines via rhodium-catalyzed addition of unbiased benzylic C–H bonds to cyclic N-sulfonyl ketamines throughπ-coordination.This strategy enables the synthesis of a diverse range of N-sulfonyl amines,and subsequent diversification of the addition products showcases the synthetic potential of this protocol.展开更多
The guanine radical cation(G?+)is formed by one-electron oxidation from its parent guanine(G).G?+is rapidly deprotonated in the aqueous phase resulting in the formation of the neutral guanine radical[G(-H)?].The loss ...The guanine radical cation(G?+)is formed by one-electron oxidation from its parent guanine(G).G?+is rapidly deprotonated in the aqueous phase resulting in the formation of the neutral guanine radical[G(-H)?].The loss of proton occurs at the N1 nitrogen,which is involved in the classical Watson-Crick base pairing with cytosine(C).Employing the density functional theory(DFT),it has been observed that a new shifted base pairing configuration is formed between G(-H)?and C constituting only two hydrogen bonds after deprotonation occurs.Using the DFT method,G(-H)?was paired with thymine(T),adenine(A)and G revealing substantial binding energies comparable to those of classical G-C and A-T base pairs.Hence,G(-H)?does not display any particular specificity for C compared to the other bases.Taking into account the long lifetime of the G(-H)?radical in the DNA helix(5 s)and the rapid duplication rate of DNA during mitosis/meiosis(5-500 bases per s),G(-H)?can pair promiscuously leading to errors in the duplication process.This scenario constitutes a new mechanism which explains how one-electron oxidation of the DNA double helix can lead to mutations.展开更多
A series of dye molecules was designed theoretically.Particularly,azoles and their derivatives were chosen as the modifying groups linking to ancillary ligands of [Ru（dcbpyH2）2（NCS）2]（N3,dcbpy=4,4＇-dicarboxy2,2...A series of dye molecules was designed theoretically.Particularly,azoles and their derivatives were chosen as the modifying groups linking to ancillary ligands of [Ru（dcbpyH2）2（NCS）2]（N3,dcbpy=4,4＇-dicarboxy2,2＇-bipyridine;NCS=thiocyanato）.Density functional theory（DFT） based approaches were applied to exploring the electronic structures and properties of all these systems.The dye molecule with 1,2,4-triazole groups which exhibits a very high intensity of absorption in visible region,was obtained.Time-dependent DFT（TD-DFT） results indicate that the ancillary ligand dominates the molecular orbital（MO） energy levels and masters the absorption transition nature to a certain extent.The deprotonation of anchoring ligand not only affects the frontier MO energy levels but also controls the energy gaps of the highest occupied MO（HOMO） to the lowest unoccupied MO（LUMO） and LUMO to LUMO＋1 orbital.If the gap between LUMO-LUMO＋1 is small enough,the higher efficiency of dye-sensitized solar cell（DSSC） should be expected.展开更多
基金sponsored by the National Natural Science Foundation of China(No.22272105)the Natural Science Foundation of Shanghai(No.23ZR1423900)。
文摘Iron-nitrogen-carbon(Fe-N-C)materials with Fe-N_(4)structures have been considered as the most promising alternatives of scarce and precious platinum(Pt)for oxygen reduction reaction.Particularly,the hightemperature pyrolysis of a precursor mixture of N-containing amine polymers,Fe salts,and carbon supports,has become a popular method for the synthesis of high-performance Fe-N-C catalysts.The oxidative polymerization of amine monomers can usually proceed under acidic conditions,however,the acidcaused protonation of N-groups is not conducive to their coordination with Fe ions for the formation of high-density Fe-N_(4)sites.Here,we propose a protonation elimination strategy of soaking the polymerization products in alkaline solutions to increase Fe-N_(4)active sites.Theoretical calculations display that the Gibbs free energy change values of binding reactions between Fe ions and N-groups are-3.70 and-26.99 kcal/mol at p H 0 and 7,respectively,suggesting that the deprotonation can facilitate the Fe-N coordination.There is a two-fold increase in the number of Fe-N_(4)active sites for final Fe-N-C catalyst which exhibits significantly enhanced ORR activity and excellent Zn-air battery performance.This deprotonation effect can be applied to different amine compounds and transition-metal ions as a universal strategy for the development of preeminent non-precious metal carbon catalysts.
文摘Among all the DNA components, extremely redox-active guanine （G） and adenine （A） bases are subject to facile loss of an electron and form cation radicals （G＋＂ and A＋＇） when exposed to irradiation or radical oxidants. The subsequent deprotonation of G＋＇ and A＋＇ can invoke DNA damage or interrupt hole transfer in DNA. However, compared with intensive reports for G＋, studies on the deprotonation of A＋ are still limited at present. Herein, we investigate the deprotonation behavior of A＋. by time-resolved laser flash photolysis. The deprotonation product of A（N6-H）＇ is observed and the deprotonation rate constant, （2.0±0.1）×10 7 s-1, is obtained at room temperature. Further, the deprotonation rate con- stants of A＋. are measured at temperatures varying from 280 K to 300 K, from which the activation energy for the N6-H deprotonation is determined to be （17.1±1.0） kJ/mol by Arrhenius equation. In addition, by incorporating the aqueous solvent effect, we perform density functional theory calculations for A＋ deprotonation in free base and in duplex DNA. Together with experimental results, the deprotonation mechanisms of A＋ in free base and in duplex DNA are revealed, which are of fundamental importance for understanding the oxidative DNA damage and designing DNA-based electrochemical devices.
基金the financial support from the National Natural Science Foundation of China(22197121)Knowledge Innovation Program of Wuhan-Basic Research(2022010801010202)Research Fund Program of Guangdong Provincial Key Laboratory of Fuel Cell Technology(FC202201)。
文摘Nucleophile oxidation reaction(NOR),represented by ethanol oxidation reaction(EOR),is a promising pathway to replace oxygen evolution reaction(OER).EOR can effectively reduce the driving voltage of hydrogen production in direct water splitting.In this work,large current and high efficiency of EOR on a Ni,Fe layered double hydroxide(NiFe-LDH)catalyst were simultaneously achieved by a facile fluorination strategy.F in NiFe-LDH can reduce the activation energy of the dehydrogenation reaction,thus promoting the deprotonation process of NiFe-LDH to achieve a lower EOR onset potential.It also weakens the absorption of OH-and nucleophile electrooxidation products on the surface of NiFe-LDH at a higher potential,achieving a high current density and EOR selectivity,according to density functional theory calculations.Based on our experiment results,the optimized fluorinated NiFe-LDH catalyst achieves a low potential of 1.386 V to deliver a 10 mA cm^(-2)EOR.Moreover,the Faraday efficiency is greater than 95%,with a current density ranging from 10 to 250 mA cm^(-2).This work provides a promising pathway for an efficient and cost-effective NOR catalyst design for economic hydrogen production.
基金financially supported by the National Natural Science Foundation of China(22379044,22472053)Shanghai Pilot Program for Basic Research(22TQ1400100-5)+3 种基金Fundamental Research Funds for the Central Universities(JKD01251505,JKVD1251041)Shanghai Engineering Research Center of Hierarchical Nanomaterials(18DZ2252400)Shanghai Titan Natural Science Development FoundationShanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism(Shanghai Municipal Education Commission)。
文摘Perovskite solar cells provide an economically viable and highly efficient pathway to harness solar energy.However,the instability of the organic component in hybrid perovskites presents a fundamental challenge that constrains the longevity and performance of perovskite photovoltaics.In this study,we introduce a molecular deuteration strategy to stabilize FAPbI_(3)perovskite by replacing the active hydrogen in the N–H bond with its heavier isotope,deuterium.The reduced ground-state energy of the isotopic N–D bond induces a deuteration kinetic isotope effect,which significantly decreases the rate constant of the deprotonation reaction from 5.15×10^(−8)to 2.42×10^(−8)s^(−1).Solar cells fabricated using deuterated FAPbI_(3)thin films achieve a power conversion efficiency of 25.08%and exhibit a T97 lifetime of 1264 h under continuous one-sun illumination at 55℃.This approach paves the way for developing inherently stable perovskite materials and extending the operational lifespan of solar cell devices.
基金supported by the Science and Technology Commission of Shanghai Municipality(No.20230742300).
文摘Aerogels with regularly porous structure and uniformly distributed conductive networks have received extensive attention in wearable electronic sensors,electromagnetic shielding,and so on.However,the poor mechanical properties of the emerging nanofibers-based aerogels are limited in practical applications.In this work,we developed a synchronous deprotonation–protonation method in the KOH/dimethyl sulfoxide(DMSO)system at room temperature for achieving chitin cross-linked aramid nanofibers(CANFs)rather than chitin nanofibers(ChNFs)and aramid nanofibers(ANFs)separately by using chitin and aramid pulp as raw materials.After freeze-drying process,the cross-linked chitin/aramid nanofibers(CA)aerogel exhibited the synergetic properties of ChNF and ANF by the dual-nanofiber compensation strategy.The mechanical stress of CA aerogel was 170 kPa at 80%compressive strain,increased by 750%compared with pure ChNF aerogel.Similarly,the compressibility of CA aerogel was somewhat improved compared to ANF aerogel.The enhancement verified that the crosslinking reaction between ANF and ChNF during the synchronous deprotonation process was formed.Afterwards,the conductive aerogels with uniform porous structure(CA-M)were successfully obtained by vacuum impregnating CA aerogels in Ti_(3)C_(2)T_(x) MXene solution,displaying low thermal conductivity(0.01 W/(m·K)),high electromagnetic interference(EMI)shielding effectiveness(SE)(75 dB),flame retardant,and heat insulation.Meanwhile,the as-obtained CA-M aerogels were also applied as a pressure sensor with excellent compression cycle stability and superior human motion monitoring capabilities.As a result,the dual-nanofiber based conductive aerogels have great potentials in flexible/wearable electronics,EMI shielding,flame retardant,and heat insulation.
基金This work was financially supported by the National Natural Science Foundation of China （51273136）, Natural Science Fund of Jiangsu Province （BK20151262）, a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions （PAPD）, the Project of Scientific and Technologic Infrastructure of Suzhou （SZS201708） and Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions.
文摘Two rosamine-based pH probes 1a and 1b with pyronine-phenol skeleton were designed and synthesized by a simple one-step reaction, pH titration experiments showed that probes 1a and 1b exhibit near OFF-ON fluorescence responses around 550--750 nm towards the hydrogen ions. The pKa of the probe 1a is 8.29, while that of the probe lb increases to 12.1 because of the hydrogen bond inside it. Selective and competitive experiments indicated that both common ions and amino acids did not interfere their emission with hydrogen ions. Moreover, confocal fluorescent imaging showed that the probe la could be served as mitochondria biomarker in HeLa and Ges-1 cells.
基金supported by the National Key Research and Development Program of China (2022YFE0138900)the “Scientific and Technical Innovation Action Plan” Basic Research Field of Shanghai Science and Technology Committee (19JC1410500)。
文摘Ion-solvaing membranes(ISMs)have received extensive attention in recent years as a key component in electrochemical energy conversion and storage devices.This article provides an overview of structural composition,performance advan-tages,research progress,ion conduction mechanism and existing issues of ISMs,primarily classifying them according to the matrix structure.A detailed analysis of performance enhancement methods,key performance indicators of ISMs and performance influencing factors is also presented.The article contributes to further optimizing the design and application of ion-solvation membranes,providing theoretical support for the development of fields such as hydrogen production through electrolysis of water and electrochemical energy in the future.
基金financially supported by the National Natural Science Foundation of China(grant nos.22272121 and 21972107)We thank the core facility of Wuhan University for the measurement of XPS.We also thank the Core Research Facilities of the College of Chemistry and Molecular Sciences for the measurement of TEM.DFT calculations in this paper have been done on the supercomputing system in the Supercomputing Center of Wuhan University.W.L.conceived and supervised the project.H.J.and Z.L.synthesized the electrocatalysts and performed the catalytic tests and characterization.J.Z.performed the DFT calculations.W.L.and H.J.wrote the manuscript.All the authors discussed the results and assisted during the manuscript preparation.
文摘The development of a highly efficient noniridium-based oxygen evolution reaction catalyst is the key to realizing large-scale commercial application of the proton-exchange membrane water electrolyzer.RuO_(2)is the most promising alternative to IrO_(2),but if usually suffers from lattice-oxygenmediated corrosion and sluggish proton transfer kinetics under acidic media.Herein,we propose an effective strategy of embedding RuO_(2)nanoparticles into a N-doped carbon support,termed as RuO_(2)-NC,to simultaneously prevent Ru dissolution and accelerate the bridging-oxygen-assisted deprotonation process.The obtained RuO_(2)-NC electrocatalyst presents high activity with an overpotential of 159 mV to reach 10 mA cm^(−2) and remarkable stability for over 240 h.Structural investigation and theoretical calculations reveal that the electron-rich NC substrate,as an electron donor,provides a buffered charge compensation to protect RuO_(2)from excessive oxidation and lattice oxygen loss by switching into a conventional adsorbate evolution mechanism(AEM).More importantly,the activated bridging oxygen(Obri)sites can facilitate the deprotonation of*OOH intermediates,leading to an optimized bridging-oxygen-assisted deprotonation AEM pathway.
文摘Phosphonium or arsonium salt with primary alcohol can undergo the tandem reaction of deprotonation-oxidation-Wittig reaction in the presence of sodium hydroxide and manganese dioxide, providing a general and efficient method for the stereoselective synthesis of (E) -α, β-unsaturated enoates.
基金supported by the National Natural Science Foundation of China(No.22209126).
文摘Efficient and stable electrocatalyst for oxygen evolution reaction(OER)in acidic environment is vital for polymer electrolyte membrane water electrolysis(PEMWE).In this work,we have devised the formation of heterostructured RuO_(2)/MnO_(2)with nanoflower structure for acidic OER catalysis.Compared to commercial RuO_(2),the overpotential at 50mA/cm^(2)is decreased by 36 mV,corresponding to a 3.7-fold better mass activity.The boosted acidic OER performance is attributed to the heterostructure inducing more electrons are filled in e_(g)orbital of Ru atom triggering a better deprotonation of bridge oxygen atom in Ru-O_(bri)-Mn structure evidenced by pH-independent cyclic voltammetry test.Moreover,RuO_(2)/MnO_(2)sustains its acidic OER activity within 20 h,longer than commercial RuO_(2).The membrane electrode assembly(MEA)test suggests than only 2.18 V is required to achieve a current density of 5 A/cm^(2).The theoretical calculation reveals that the e_(g)filling of Ru atom is increased from 2.18 to 2.39 after MnO_(2)incorporation,reducing the energy for the formation of ∗OOH moiety.
基金financially supported by the Natural Science Foundation of Hunan Province(2023JJ40608,2024JJ6413)the Majoy Project of the Education Department of Hunan Province(24A0610).
文摘Proton exchange membrane water electrolysis(PEMWE)technology is widely recognized as a cornerstone for green hydrogen production,offering high operational current densities exceeding 1.0 A cm^(-2),rapid dynamic response capabilities,and zero-carbon emission characteristics[1].However,the sluggish kinetics of oxygen evolution reaction(OER)at the anode presents a critical bottleneck for large-scale commercial deployment(Fig.1(a)).Despite significant advancements through electronic structure modulation[2]and coordination environment optimization[3],the deprotonation energy barrier of oxygen-containing intermediates and the stability of active sites under acidic conditions remain unresolved challenges.
文摘Tetracycline hydrochloride(TCH)exists in various forms in aqueous solution due to pH changes,which not only alters the reactivity of TCH,but also affects the process of reactive oxygen species(ROS)attacking the molecule.Therefore,the rational design of piezo-photocatalytic materials coupled with a comprehensive understanding of the degradation mechanisms of various TCH species constitutes a critical approach to addressing tetracycline antibiotic contamination.In the design and preparation of piezo-photocatalysts,controlling the oxygen vacancy concentration is crucial as it governs the coupling efficiency between piezoelectric response and photocatalytic activity,as well as the strength of spontaneous polarization.Meanwhile,the morphology of the material is a key factor influencing the migration pathways of charge carriers.In this work,hollow spherical Bi_(4)Ti_(3)O_(12) was synthesized using an inorganic titanium source,demonstrating exceptional piezo-photocatalytic activity.The degradation rate was 1.57 and 5.29 times higher than that of traditional spherical and plate-like morphologies,with a rate constant of k=0.127.In an innovative approach,density functional theory calculations of local softness and hyper-softness were employed to analyze the reactivity changes of TCH in its different deprotonated states toward reactive oxygen species.Combined with molecular electronegativity analysis,the factors influencing the degradation efficiency were identified.This study provides a solid foundation for developing efficient and environmentally friendly piezo-photocatalysts and offers new insights into the degradation mechanism of TCH.
基金This work was supported by the National Natural Science Foundation of China (No. 20371028, 20671052)the Natural Science Foundation of Tianjin (No. 023605811)
文摘The title compound, 1,2-bis-（p-nitro-phenylsulfonamido）-4,5-dinitrobenzene, was synthesized and characterized by elemental analysis, IR and 1H NMR. A pale yellow prism crystal of C23H26N8O13S2 （Mr = 686.64） was obtained in DMF solution and determined by single-crystal X-ray diffraction method. It crystallizes in triclinic system, space group P1 with a = 10.346（4）, b = 12.210（5）, c = 12.976（5）A , α = 108.220（8）, β = 99.482（4）, γ = 95.490（4）°, V = 1516.7（10） A^3, Z = 2, Dc = 1.504 g/cm^3, F（000） = 712, μ = 0.254, Mr = 686.64, the final R = 0.0561 and wR = 0.1487. One sulfonamido group of the title compound is deprotoned and forms N（3）=C（13）. The crystal involves N,N-dimethylamine from the decomposition of DMF and the proton is transferred to N,N- dimethylamine. It is a strong proof for the characterization of deprotoned recognition compound by X-ray single-crystal structure.
文摘The isomerization of hydrofluorocyclopentenes promoted by fluoride anion was investigated. It was found that two processes were responsible for interconversion of the isomers: an allylic syn-addition/elimination of fluoride anion that does not change the mutual positions of hydrogen atoms but is responsible for transfers of fluorine atoms, and a fluoride anion-assisted deprotonation/protonation which does not change the mutual positions of fluorine atoms but is responsible for transfers of hydrogen atoms. In the deprotonation, HF can easily capture excess fluoride anion to form HF2- anion which can probably inhibit the protonation.
基金support from the National Natural Science Foundation of China(22090031,22090030,22288102),Qinghai Salt Lake Industry Group Co.,Ltd.
文摘Aqueous rechargeable batteries using abundant multi-ion cations have receivedincreasing attention in the energy storage field for their high safety and low cost.Layered double hydroxides(LDHs)possess a two-dimensional structure andexhibit great potential as cathodes for multi-ion intercalation.However,theinsufficient active sites of LDHs result in low capacities in the discharging process.Interestingly,the LDHs after the deprotonation process exhibit favorable electrochemicalperformance of multi-cation intercalation.The deprotonation process ofLDHs has been widely found in the oxygen evolution reaction and energy storagefield,where LDHs lose H in laminates and converts to deprotonatedγ-phaseMOOHs(MOOs).Herein,we take a comprehensive overview of the dynamicsstructure transformation of the deprotonation process of LDHs.Furthermore,thedevelopment of advanced aqueous battery cathode and metal battery anode basedon deprotonated LDHs for energy storage is explored and summarized.Finally,theperspective of deprotonated LDHs in the energy storage field is discussed.
基金supported by the National Natural Science Foundation of China (No.21573208, No.21573210, and No.21873089)the National Key Basic Research Foundation of China (No.2013CB834602)
文摘Raman spectra of 1,2,4-triazole-3-carboxylate (TC- anion) and its ring-deprotonated deriva- tive (dpTC2- dianion) in aqueous solutions were measured respectively. The density func- tional theory calculations were performed using MN15 functional and PCM solvent model to investigate their structures, as well as the vibrational frequencies and Raman intensi- ties. With the aid of the calculated spectra, all the observed Raman bands of dpTC2- were clearly assigned, with taking into account the deuteration shifts. Moreover, various protonic tautomers of TC- anion were compared in the present theoretical calculations, and 2H- tautomer was found more stable. The experimental Raman spectrum of TC- solution was roughly consistent with the calculated spectrum of the monomeric 2H-tautomer of TC-, but some splits existed for a few bands when compared to the calculated spectra, which might be contributed by the hydrogen-bonding dimers of TC-.
基金funded by National Natural Science Foundation of China(Nos.52075138 and 61964006)Hainan Provincial Natural Science Foundation(No.2019RC032)Hainan Province Science and Technology Special Fund(No.ZDYF2022SHFZ033)。
文摘Nanopore detection is a hot issue in current research.One of the challenges is how to slow down the transport velocity of nanoparticles in nanopores.In this paper,we propose a functional group modified nanopore.That means a polyelectrolyte brush layer is grafted on the surface of the nanopore to change the surface charge properties.The existing studies generally set the charge density of the brush layer to a fixed value.On the contrary,in this paper,we consider an essential property of the brush layer:the volume charge density is adjustable with pH.Thus,the charge property of the brush layer will change with the local H+concentration.Based on this,we established a mathematical model to study the transport of nanoparticles in polyelectrolyte brush layer modified nanopores.We found that pH can effectively adjust the charge density and even the polarity of the brush layer.A larger pH can reduce the transport velocity of nanoparticles and improve the blockade degree of ion current.The grafting density does not change the polarity of the brush charge.The larger the grafting density,the greater the charge density of the brush layer,and the blockade degree of ion current is also more obvious.The polyelectrolyte brush layer modified nanopores in this paper can effectively reduce the nanoparticle transport velocity and retain the essential ion current characteristics,such as ion current blockade and enhancement.
基金the National Natural Science Foundation of China(Nos.22271235,22071198)the“Pioneer”and“Leading Goose”R&D Program of Zhejiang(No.2022SDXHDX0006)the Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(No.2020R01004)for research support。
文摘Mannich-type reactions are a widely used method for the synthesis of amines due to the readily availability of nucleophiles and electrophiles.However,the inclusion of alkylarenes instead of active carbon pronucleophiles such as aldehydes and ketones in these addition reactions has been a challenge due to the inherent difficulty of benzylic deprotonation.In this study,we present a novel approach for the construction of N-sulfonyl amines via rhodium-catalyzed addition of unbiased benzylic C–H bonds to cyclic N-sulfonyl ketamines throughπ-coordination.This strategy enables the synthesis of a diverse range of N-sulfonyl amines,and subsequent diversification of the addition products showcases the synthetic potential of this protocol.
文摘The guanine radical cation(G?+)is formed by one-electron oxidation from its parent guanine(G).G?+is rapidly deprotonated in the aqueous phase resulting in the formation of the neutral guanine radical[G(-H)?].The loss of proton occurs at the N1 nitrogen,which is involved in the classical Watson-Crick base pairing with cytosine(C).Employing the density functional theory(DFT),it has been observed that a new shifted base pairing configuration is formed between G(-H)?and C constituting only two hydrogen bonds after deprotonation occurs.Using the DFT method,G(-H)?was paired with thymine(T),adenine(A)and G revealing substantial binding energies comparable to those of classical G-C and A-T base pairs.Hence,G(-H)?does not display any particular specificity for C compared to the other bases.Taking into account the long lifetime of the G(-H)?radical in the DNA helix(5 s)and the rapid duplication rate of DNA during mitosis/meiosis(5-500 bases per s),G(-H)?can pair promiscuously leading to errors in the duplication process.This scenario constitutes a new mechanism which explains how one-electron oxidation of the DNA double helix can lead to mutations.
基金Supported by the National Natural Science Foundation of China(Nos.20973076,21003057)the Specialized Research Fund for the Doctoral Program of Higher Education,China(No.20110061110018)
文摘A series of dye molecules was designed theoretically.Particularly,azoles and their derivatives were chosen as the modifying groups linking to ancillary ligands of [Ru（dcbpyH2）2（NCS）2]（N3,dcbpy=4,4＇-dicarboxy2,2＇-bipyridine;NCS=thiocyanato）.Density functional theory（DFT） based approaches were applied to exploring the electronic structures and properties of all these systems.The dye molecule with 1,2,4-triazole groups which exhibits a very high intensity of absorption in visible region,was obtained.Time-dependent DFT（TD-DFT） results indicate that the ancillary ligand dominates the molecular orbital（MO） energy levels and masters the absorption transition nature to a certain extent.The deprotonation of anchoring ligand not only affects the frontier MO energy levels but also controls the energy gaps of the highest occupied MO（HOMO） to the lowest unoccupied MO（LUMO） and LUMO to LUMO＋1 orbital.If the gap between LUMO-LUMO＋1 is small enough,the higher efficiency of dye-sensitized solar cell（DSSC） should be expected.
